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elementary MAY -JUNE 1979

1. 28 10033021 TRANSISTORS low powar silicon hfa 60 T 2 92 z 627 1 ALLEN BRADLEY POT 10K 2 1 4 watte typa J 2 x shalt 71748 50 ASST RED LEDS 20 or better various styles and typas n 5624 a 10 G E POWER TAS TRANSISTORS 040A 1 N2 soms NB TO 220 a ass etirrwayq a aia 2 4 BLOCK TRIM POTS 200K s 2535 oo 4 1 12VDC SMIL REED RELAY spet N O 2200 ohms 7 8 z 8 16 x 8 16 wssa8 4 29 SO TEMP COEFFICIENT VOLTAGE REF DIOOES asst velt 503 S647 ssa eee 12 SHINMY TRIM POTS PRECISION sect styles value SOY yield 3380 60pc PRECUT PRETINNED WIRE various lengths and calors L 1971 60 MINI RESISTORS for PC appi vart 1 8W color coded 2235 20 NYLON GEARS hi quality sect sizas 7 3446 10 4 POTS sudic taper plastic snap in mounting 5124 10 142 MEG DUAL POTS sudlo tapar snap in mnt 125 d SO 1 AMP ZENERS wide ssst of valuss untasted 7 1964 cece eevee 4 29 12 SCR S amp TRIACS 10 AMP ssst veluss untested han 3 QUADRACS 10 AMP 100 primes 350 100 200 V TO 220 20 MINI RECTIFIERS 1 AMPS 25V spony asiel 25374 10 1N4007 1000V MINI RECTIFIER spony cana axel leads 2383 7S MOLEX CONNECTOR Type M1938 4 makes 14to 40 din sockats a SOIF TRANSFORMERS seet sizas 35A9 kis 3 asa a Wale q esia s Sal ds 10 T V CHEATER CORD JACKS S 19 asaasasassasasisaaasasaasa 1 29 10
2. umc Oe H electronics of the future systems and more from AL 40 09 NATIONAL TECHNICAL SCHOOLS O Color TV Servicing OB amp W TV and Radio Servicing O FCC License Course L Electronic Communications Ll Electronics Technology C0 Audio Electronics Servicing O Digital Electronics O MicroComputers MicroProcessors Name _ Address _ _ E Apartment Number Age Cy e State Zip LiCheck if interested in G I Bill information Dept 222 059 4000 South Figueroa Street Los Angeles California 90037 Please send FREE Color Catalog and Sample Lesson LiCheck if interested ONLY in classroom training in Los Angeles im Om EEO G G jeybig 41 Q wwe th rmore any leakage within C3 will exert yet another influence on the time delay the leakier the capacitor the longer the charging time With this in mind it is wise to use a new high quality electrolytic capacitor for C3 Power Supply Power for the Third Ear comes from five D cells in series yielding 7 5 volts Electrolytic capaci tor Cl keeps the power supply s im pedance low Inactive the Third Ear draws only 2 milliamps but current consumption jumps to 22 mA when the circuit is active At these small rates of discharge D cells will last a long time Some readers might prefer to see the Third Ear powered by an AC sup ply however transformers hum at 60 Hz and the Third Ear is sensitive enough to be triggered if a t
3. plate etc SBI SOLAR CELLS TERENA ee PARTS LIST FOR SOLAR SWINGER C1 365 uF variable capacitor C2 5 uF electrolytic capacitor 15 volts D1 1N34A germanium diode J1 any jack to fit headphones L1 ferrite antenna coi Radio Shack 270 1430 or equiv Q1 Q2 2SA52 transistor RCA SK 3003 GE 2 Radio Shack 276 2004 R1 R3 10 000 ohm resistor watt R2 220 000 ohm resistor 4 watt R4 15 000 ohm resistor 1 4 watt SB1 two solar cells Radio Shack 276 120 or equiv Misc headphones of 1000 2000 ohms bolt and nut tube base old tubes wooden ELEMENTARY ELECTRONICS May June 1979 The only wood work needed is to make two large holes in the base One for the tube and one for the tuning capacitor A bolt through the base holds the tube in place Wiring in the Parts Mount the an tenna coil Li in the center of the Support wires since it is the largest component Solder the top wire to pin 2 and the bottom terminal to pin 1 Leave it loose until all parts are solder ed and then use a dab of silicone ces ment to hold it in place Solder the col lector terminal of QI and negative terminal of C2 to support wire number 2 Keep the leads fairly short and place a pair of long nose pliers next to the transistor body as a heat sink The emitter terminals from each transistor will tie to terminal support number 1 Now solder in all small components to their correct su
4. INFORMATIVE HANDBOOK For people with an interest in electronics and desire to know more Covers basic electricity resistors capacitors micro waves facts on frequency about fuses circuit break ers crystals and much more Send 1 50 for your copy includes postage to Electronics Theory Hand bouk 380 Lexington Ave N Y NY 10017 BUSINESS OPPORTUNITIES BECOME our Mail Order Distributor with 1 00 for supplies Free Booklet Audit Controls Box D 35 Emerson NJ 07630 BORROW ANY AMOUNT Enjoy A 1 credit Keep money in bank get 80 more Send Stamp Vernon Box 75010 HH Oklahoma City 73147 f MILLIONS in Mail Free Secrets Box 6226 Toledo OH 43614 Transworld 3 NEW Luxury Car Without Cost Free details CODEX A Box 6073 Toledo OH 43614 1000 PROFIT Bronzing Baby Shoes Free Lit efature NEC Box 1904 DG Sebring FL 33870 Place your ad in one of our SPECIAL COMBINATIONS Combo 1 BUSINESS OPPORTUNITIES Cont d STAY HOME EARN BIG MONEY addressing en velopes Genuine offer 10 Lindco 3636 DA Peter son Chicago 60659 WHOLESALE Rubber Stamp Outfits Supplies Cat alog 1 00 Martin peep Major Jefferson City MO 1 500 Monthly Clipping Newspaper items Experience unnecessary Free Details American 1108 Colonial Inkster MI 48141 l gt BORROW 25 000 interest free indefinitely Any one Free report Executive I05 Box 368 Buford GA 30518 BUMPER S
5. 20 1N4148 SWITCHING DIODES 4 nsec axial z 3000 10 AMP QUAORACS w trigger diode up 600y eg S MICRO SWITCHES push asst types 3011 A 40 SQUARE DISC STYLE CHOKES color codad 3203 30 TRANSISTORS T082 2N4400 esriss u test s 3291 TRANSISTORS TRANSFORMERS sudio Intar ste mini s 3295 15 PRINTED CKT TRIMMER POTS sect vatues stc z 3346 7 2N 3055 HOBBY NPN TRANSISTORS T0 3 U3771 10 PNP 30 WATT T0 3 TRANSISTORS hobby s 3772 SO TUBE SOCKETS 4 5 68 7 pin tubes asst 3839 1 10 AMP POWER TAB QUADRAC 200 PRY T0220 2 trigger 2 1590 10 BULLET RECTIFIERS 1 5 amp 200V axial 84 00 00 66 ce cece een ae een 6 READOUTS MAN 3 common cath LED the claw RED v 3338 8 LEDS sest sizes and shapes red green yellow amber 3863 PHOTO FLASH ELECTRO CAP 600 MF 360Y 3897 1 1 29 2 CIRCUIT BREAKERS glaes sealed axisi rated 1 amp 3905 MICRO MINI TOGGLE SPST 2 pos on off 125V 3 amps s 3976 S SLIDE VOLUME CONTROLS asst of popular vaiuas for HiFi 42318 15 COAX LEOs single lasad pin haad styla Color Redi 1788 60 TERMINAL STRIPS form two luge up Solder type 35A3 60 CERAMIC CAPS Incl NPO s nag coef N7 0 8 seat values 10 T FM SPLICERS tor 300 ohm shielded twin lead Bakelite r 5547 10 1SV ZENERS 400m w saisi glass case 7 5404 200 for 301 100 for 1 30 12 tor 1 30 Bitor 4 30 10 tor 1 30
6. IPG 1 INVISIBLE PAIN FIELD GENERATOR This amazing simple hand held device is about the size of a pack of Cigarettes and generates a directional held of moderate to inten Sive pain in the lower part of the head up to a range of 50 De vice ts simple and economical to make IPG 1 PLANS 6 00 IPG 1K ALL PARTS 39 50 IPG 10 ASSEMBLED amp TESTED FOR ANIMAL CONTROL 49 50 LASERS RUBY LASER RAY PISTOL Produces highly intense red beam capable of burning A hazardous device PLANS PARTS SOURCES 15 00 HIGH POWERED CARBON DIOXIDE BURNING AND CUTTING Complete plans and all parts sources 10 00 SOLIO STATE IR 12 WATTS with duil in power supply plans 6 00 Complete kit with collimator 84 50 POCKET LASER pulsed visible red plans 6 00 Complete kit 39 50 Also complete plans and parts Sources lor RUBY YAG NEQDYNIUM HeNe ARGON DYE NITROGEN and many more lasers F SECURITY SNP 2 SNOOPER PHONE Dial home or office phone while on vacation activating sensitive mike without phone ringing Excellent property protection and intrusion device SNP2 PLANS 7 00 SNP2K ALL PARTS 49 50 SNP20 ASSEMBLEO AND TESTED 89 50 LONG RANGE XMTR PLANS 6 00 SEE IN THE DARK PLANS 8 00 DIRECTIONAL SHOTGUN MIKE PLANS 7 00 SUPER SENSITIVE PARABOLIC MIKE PLANS 7 00 SOUND amp TELEPHONE OPERATED TAPE RECORDER 5 00 CATALOG ON PLANS KITS amp FINISHED UNITS 1 00 Send check or money order to SCIENTIFIC SYSTEMS Dept A
7. i 18 Ib 1 mA 8 100 Findic 19 Ib 10 vA 8 250 Find Ic 20 Ib 0 1 mA Ic 7 5 mA Find ANSWERS 17 0 1 A or 100 mA 18 100 mA 19 2500 zA or 2 5 mA 20 75 This set of questions will serve as a summary of the first part of this chapter You should be able to answer all the questions Use a separate sheet of paper for your diagram and calculations QUESTIONS 21 Draw the circuit in mada 13 and show the paths of 1 Ib and Ic 22 Which current controls the other 23 Which is the larger current Ib or Ic S She 24 lb 6 aA B 250 Fmd IC Me ie 25 Ic 300 mA g 50 Find Ib me h ANSWERS 21 Refer to frame 13 to see if the figure is correct 22 lb base current controls Ic collector current 23 Ic 24 1 5mA 25 6 mA f THE TRANSISTOR EXPERIMENT The object of the following experiment is to find 8 of a particular transistor by measuring several values of base current with their corresponding values of collec tor current These values of collector current will be divided by the values of the base current to obtain 8 The value of 8 will be almost the same for all the measured values of current This will ot that 8 is a constant for a transistor As long as the circuit is set up measure the collector voltage for each current value This will demonstrate experimentally some poi
8. Because we rc special ists we have to stay ahead At CIE we ve got a position of leadership to maintain Here are some of the ways we hang onto it Our step by step learning includes hands on training At CIE we believe theory is important And our famous Auto Programmed Lessons teach you the principles in logical steps But professionals need more than theory That s why some of our courses train you to use tools of the trade like a5 MHz triggered sweep solid state oscilloscope you build yourself and use to practice trouble shooting Or a beauty ofa 19 inch diagonal Zenith solid state color TV you use to perform actual service operations Our specialists offer you personal attention Sometimes you may even have a question about a specific lesson Fine Write it down and mail it in Our experts will answer you promptly in writing You may even get the specialized knowledge of all the CIE specialists And the answer you get becomes a part of your per manent reference file You may find this even better than having a class room teacher ELEMENTARY ELECTRONICS May June il Pick the pace that s right for you CIE understands people need to learn at their own pace There s no pressure tokcepup no slow learners hold you back If you re a beginner you start with the basics If vou already know some elec tronics you move ahead to your own level Enjoy the promptmess of CIE
9. s same day grading eyele When we receive your lesson before noon Monday through Satur day we grade it and mail it back the same day You find out quickly how well you re doing CIE can prepare you for your FCC License For some electronics jobs you must have your FCC License For others employers often consider ita mark in your favor Either way it s government certified proof of your specific knowledge and skills More than half of CIE s courses prepare you to pass the government administered exam In continuing surveys nearly 4 out of 5 CIE gradu ates who take the exam get their Licenses For professionals only CIE training is not for the hobby ist It s for people who are willing to roll up their sleeves and go to work to build a career The work can be hard sure But the benefits are worth it Send for more details and a FREE school catalog Mail the card today If it s gone cut out and mail the coupon You ll geta FREE school catalog plus com plete information on independent home study For your convenience we ll try to have a CIE representa tive contact you to answer any ques tions you may have Mail the card or the coupon or write CIE mentioning name and date of this magazine at 1776 East 17th Street Cleveland Ohio 44114 a TS ee TF E Ni W Patterns shown on TV and oscilloscope screens are simulated ICI Cleveland Institute o
10. 4 95 690 Logica Coic TV Troubleshooting 240 p 151 APPLIANCES ELECTRICITY amp ENERGY 1063 How To install Your Own Home or Mobite 921 Dyrect Current Motors 252 p 172 987 Hearing Aid Handbook 336 p 224 ii 8 95 913 Complete Hdbk of Elecirical House Wiring 476 p 196 tl 6 95 906 Homeowner s Gde to Solar Heating Cooling 196 p 113 it 4 95 962 Microwave Oven Service amp Repair 420 p 210 1l 9 95 903 Guide to Modern Energy Efficient Heating Cooling Sys 5 95 758 How to Completely Secure Your Home 224 p 162 i 5 95 1030 101 Practical Uses tor Propane Torches 140 p 93 il Ee 4 95 6 95 6 95 5 95 6 95 5 95 4 95 5 95 6 95 5 95 4 95 1495 820 Centra Heating Ar Cond Repair Guide 320 p 285 4 est amp Repair 160 p 102 515 Small Appliance Repair Guide Vol 1 224 p 100 l 917 How to Repair Small Gasoline Engines 392 p 251 l 904 Homeowner s Guide to Saving Energy 288 p 169 l 745 The Home Appiiance Clinic 195 p 61 885 How to Repair Hame Kitchen Appiiances 294 p 205 1 920 Complete Hdbk of Locks amp Locksm lhing 392 p 348 l 855 How to Repair Home Laundry Appliances 280 p 137 l 715 Small Appiance Repair Guide Vol 2210p 119 1 555 Major Appliance Aepar Guide 288 p 278 l 5 95 671 Electncal Wiring Lighting for Home Office 204 p 15511 4 95 520 How to Repair Home Auto Ar Conditioners 208 p 10011 595 295 Aetrigeration 160 p 53 3 95 u 1073 Am
11. 50 for 1 30 60 for 1 30 120 for 1 30 110 for 4 30 100 for 4 30 2for 1 30 24 for 1 30 120 for 1 30 1260 tor 1 30 120 for 1 30 100 tor 1 30 20 for 1 30 120 for 1 30 40 for 1 30 150 for 1 30 70 for 1 30 8 for 1 30 200 for 1 30 200 for 1 30 200 for 1 30 24 for 1 30 100 for 1 30 100 for 1 30 20 for 1 30 20 for 1 30 12for 1 30 60 for 1 30 12for 1 30 100 for 1 30 10 for 1 30 12for 1 30 100 for 1 30 40 for 1 30 2for 1 30 A2Zfor 1 30 16 for 1 36 40 for 1 30 12 for 1 30 10 fer 1 30 BO for 4 30 60 for 1 30 12 fer 1 30 30 for 1 30 14 for 1 30 20 for 1 30 100 for 1 30 2 for 1 30 20 for 4 30 12 for 1 30 16 for 1 30 2 for 1 30 4for 1 30 2for 1 30 10 for 1 30 30 for 1 30 120 for 1 30 120 for 1 30 20 for 1 30 20 fer 1 30 12 1 5 LAMP AND SOCKET SET 200ma T2 style 3956 10 RCA PHONO JACKS chaesis mount teflon baee 5119 15 THERMISTORS asst typee etyies A valuse 2048 ods 4 5 DIGIT 7 SEGMENT READOUTS in flat pok case 3616 E A AEE E s ia 29 4 BLOCK TRIM POTS SK s2S36 Se a Oe 1 29 1 FOTO FET N CHANNEL Cryetalonics Sealed Effect Transistora 61169 1 29 1 VOLTAGE REGULATOR T0202 casa 12V GOOMA s i FOO ss 1 29 1 3 DIGITS OM A DIP LED red DL 33 s1887 lime M Sema as 1 29 3 MM5262 2K DYNAMIC RAM specify type z 3459 10 2N711 HIGH SPEED SWITCHING TRANSISTORS TO 8 non 3374 2 15W
12. Box 1201 Wilmington NC 28402 HOW TO WRITE A BESTSELLER Amazing new method Free details King Dept M C12 236 Spen cer Wildwood NJ 08260 MILLIONS in Mail Free Secrets Transworid 3 Box 6226 Toledo OH 43614 How To Wme n Classified Ad That Pulls and igy are nm to Haw t S07 Weight In Gold t MAKE YOUR CLASSIFIED AD PAY Get How to Write A Classified Ad That Pulis Includes Certificate worth 2 00 paras a classified ad in this publication Send 1 50 plus 25 postage to R S Wayner Davis Publications Inc Dept CL 380 Lezington Avenue New York NY 10017 PLEASE Be sure to include your zip code when ordering merchandise from classified advertisements You ll receive faster delivery GUARANTEED big money making program Abraxas Ent P O Box 6072 Evansville IN 47712 EXCITING Second Income Working At Home Free Details Write C T amp S Enterprises Box 2442 D Loves Park IL 61132 f HOMEWORKERS Needed 600 weekly addressing mailing Ideal for students Box 1874 Htfd CT 06144 2500 Monthly Mailing Circulars Dealers Wanted Details 25 refundable Enterprises Box 408 I0O Erie PA 16512 THREE Steps to Success Send sase Malling Systems G P O Box 2420 N Y NY 10001 REAL Estate Appraising Fantastic profits AAR Box 6125 B Hayward CA 94544 500 CASH ADVANCE stuff 1000 nvelopes In formation self addressed sta
13. Cartridge Tape Players 294 p 196 505 Installing amp Servicing Home Audio Systems 255 p 136 il 67 Elements of Tape Recorder Circuits 224 p 145 il 642 Jap Radio Record amp Tape Player Service Manual 228 p 86 Installing Hi Fi Systems 224 p 152 amp 59 Servicing Record Changers 224 p 173 TV RADIO amp ELECTRONIC SERVICING 1082 TV Fieid amp Bench Servicer s Handbook 308 p 157 l 1119 Coior TV Trouble Factbook 1h Edition 532 p 1028 How To Recarr Video Games 270 g 182 l 939 Hedok of Marine Electronic amp Electrwal Systems 546 p 901 CET License Handbook 2rid Edition 448 p 169 il B21 TV Troubleshooter s Handbook 3rd Ed 448 p over 300 il 563 Begnaers Guide to TV Repair 176 9 50 il 4 95 956 Fire amp Thett Security Systems 2nd Ed 192 p 108 il 55 95 876 Colo TV Case Histories lilustrailed Yo 2 352 p 243 il 736 Color TV Case Histories Illustraled 238 p 219 ii 809 Photo Guide Solid State Color TV Troubles 224 p 169 il 772 Troubieshooting with the Dual Trace Scope 224 p 252 il 738 TV Schematics Reading Between the Lines 252 p 188 h 605 Install Svcing Electr Protective Systems 252 p_aver 160 696 TV Tuner Schematic Servicing Manual Vol 1 224 p 287 979 TV Tuner Schematic Servicing Manual Voi 2 200 p 374 il i 7 95 6 95 6 95 4 95 5 95 3 95 495 5 95 6 95 9 95 6 95 7 95 7 95 5 95 5 95 5 95 55 95 5 95 6 95 6 95 5 95
14. For example tuning up your tape 7 player all about radios whys and hows of turntables care and feeding xX of speakers see gt NO NONSENSE TESTS The scoop on Pioneer s TP 900 FM stereo car radio How well does GE S NiCad charger pep up your pooped batteries What s lt your best bet in video games Plus J at 2 help in making buying decisions S 2 N lt a O lt oN lt x oN Bor oe g oe J e w gion F Z o sQ 4 Q O os x P q u F oo O lt p lt Ga 2 Palomar Loop Continued from page 56 ize the Palomar s nulling But if you are limited for BCB DXing to a re ceiver s built in loopstick antenna or a piece of wire lying on the floor or sta pled to the moulding then the Palomar will pay off in almost unbelievable per formance you will actually dig out signals you never knew existed The Palomar loop antenna system works best in a frame house brick and stucco will reduce maximum perform Ca sition the antenna near a window fac ing the direction from which you want to receive signals Aluminum siding generally acts as an almost total shield if the siding is grounded according to the electrical code and the loop anten na might not offer any improvement in reception unless located in a win dow Our tests in an aluminum sided home indicated poor reception when the siding totally surrounded the loop When there was a
15. H9DO22 24 Q Which magazine has the widest scope of equipment test reports A hifi stereo Read it regularly for the most in consumer audio information and advice Allow 6 to 8 weeks for delivery of first copy Hi Fi Stereo BUYERS GUIDE gives you the absolute tops in number of equipment test reports per issue Pe e pa a If you re a best buy buyer don t miss a single Issue 8d ee 2 Hi j CASSETTE DECK FEATURES wiwa Hi Fi Stereo BUYERS GUIDE Box 1855 GPO 5 12 off newsstand rate Name Address City State Zip CREDIT CARD OWNERS OD 18 issues for 8 94 Canada other countries 18 issues 12 00 Credit Card Mai this coupon to New York NY 10001 2 97 off regular subscription rate re Pg th i PS SS SSS U 1 DK central A world of SWL info By Don JENSEN ADIO MOSCOW IS TRYING to cover all R the bases in its attempt to increase its English speaking audiences especial ly those right here in North America Faithful and diligent SWLs have no doubt already noted that it is now pos sible to hear English programs from Radio Moscow around the clock thanks to the new World Service insti tuted last fall to fill around the former evening services to North America The expanded World Service in di rect competition with the British Broad casting Corp and the Voice of Amer ica has a heavy emphasis on news and current events It is
16. If you use an external antenna make sure it isn t grounded Check for bare antenna wires touching tree limbs of insulators which have become saturated with moisture after several years use More difficult interference problems from overload images are the resuit of more complex mathematical relation ships which can be expressed in mul tiples called harmonics of he fre quencies involved If you are receiving very strong signals from VOA Green ville on 6190 and Radio Canada Inter national 6140 they might produce an image on 6240 kHz 2 x 6190 minus 6140 This calculation is derived alge braically from the relationship 6190 R TUNED TO THE F CIRCUITS i L STATION S FREQUENCY LOCAL OSC 455 KHz ABOVE TUNED FREQUENCY INTERMEDIATE FREQUENCY CIRCUITS AT 455 KHz To AUDIO CIRCUITS This block diagram shows how an image signal is formed It will always be twice the intermediate frequency below the station Double conversion receiver may cure image Shared with utilities Shared with amateurs A aoe i a 11706 1105 4 15100 15450 1770017900 21450 21750 2560026100 t minus 6140 plus 6190 Note the dif ference between the image frequency and the real frequency is relatively slight so your antenna tuner control won t help To make things still more compli cated such mixing may not be occur ing in your receiver or antenna at all If two tra
17. TAKING ON TRANSI STORS Our ir Introductory Course Page 79 CCE 02342 Get RA DIO AC TIVE Build Signal Snarer gt Shine with Solar Swinger Be Your Own FM Broadcast Cure Bad Ham Habits OGETHER HIRD EAR und servant D ie gt w gy d cem Xr gt I a C m a lt gt amp ru T o 3 ED iri r gt 4 ty r lt m r wd gt H BL T8bL0 TN d ___ REPORTS a Heath Active Audio Processor 7 Palomar BCB Loop Antenna Redco Frequency Counter S af T SOL 20 Home Computer Kit N gt zs iz J T DL S gt l f ae a oaves PuaLicaTion FOR THOSE OF YOU WHO ARE HAVING SECOND THOUGHTS ABOUT YOUR FIRST CB Move up to the all new Cobra So if you re having second CIGIL It s the third generation of thoughts about your first CB make the trucker proven Cobra 29 And your next CB the Cobra 29GTL like the 29 and the 29XLR before We back it with a guaranteed it it advances the state of the art warranty and a nationwide network transmitter circuitry has been of Authorized Service Centers refined and updated to improve where factory trained technicians performance are available to help you with Receiver circuits have been installation service and advice redesi
18. Therefore WKBW and CHOW will appear on 1495 kHz Fortunately such images which can be detected via the variable het test previ ously described are usually weak and generally limited to the standard AM band Then there are the new crop of cyn thesized frequency receivers These use multiple local joscillators some of which deliberately radiate harmonics Each model has its own particular arrange ment of intermediate frequencies thus we cannot deal with them comprehen sively here However note that over leading can be a major problem with the less expensive models On the other hand simple superheterodyne local oscillator caused images are virtually eliminated by dual conversion Buying A New Receiver When it Continued on page 87 1 ELEMENTARY ELECTRONICS May June 1979 Homer L D L Davidson inside a bottie The next logical step is to build a small radio in side of a radio or TV vacuum tube We call it the Solar Swinger and it has no on off switch batteries or power supply If you want to turn the Solar Swinger off just place a cap or hood over the tube You may want to jet it play all the time it doesn t hurt a thing No need to worry about batteries running down for the little radio is solar powered It will operate in the sun shaded daylight or under a desk lamp in the evening Of course the radio won t blast your ear drums with music but you can listen to local AM broadcast stati
19. Wonderful only our floor was never as clean as this On October 29 1929 Edison reen acted the entire process the Miracle of the Millenium by re inventing the electric light at Greenfield Village By his side was Francis Jehl just as he had been a half century earlier Dig Here Edison poses with one of his later models of the incandescent lamp Note the extra neck on the bulb for bleeding out air by Jorma Hyypia U S Department of the Interior Edison National Historic Site An engraving made by J J Cade after the photograph taken of Edison and his phonograph by the famous Mat thew Brady This model used foil as recording medium nitaries watching the second invention of the light bulb included Herbert Hoover Madame Curie Gearge East man Harvey Firestone and Cyrus Eaton Another center of activity will be West Orange New Jersey where Edi son lived and worked for many years The National Park Service now main tains and conducts tours through the laboratory buildings and through Glen mont Edison s home Plans call for a series of special celebrations complete with invited dignitartes Many U S and overseas electronics corporations will celebrate the Cen tennial of Light and Thomas Edison This is rightly so because these com panies represent the breadth of activi ties with which the inventor was in volved Each organization grew one way or another from the work of t
20. s T46 5 9 wrapped wire pins into the holes One corner of the 8804 may be used for a low profile heat sink with two regulators in TO 220 packages 8804 Plugbords are priced at 21 95 singly and 19 76 each in quantities of five or more Write to Vector Electronic Company 12460 Gladsone Avenue Sylmar CA 91342 for further information Continued on page 16 ELEMENTARY ELECTRONICS May June 1979 ELEMENTARY ELECTRONICS May June 1979 BUILD 20 RADIL AND ELECTRONICS CIRCUITS PROGRESSIVE HOME RADIO T V COURSE Now Includes 12 RECEIVERS 3 TRANSMITTERS SQ WAVE GENERATOR SIGNAL TRACER AMPLIFIER SIGNAL INJECTOR CODE OSCILLATOR YOU DON T HAVE TO SPEND HUNDREDS OF DOLLARS FOR A RADIO COURSE The Edu Kit offers you an Outstanding PRACTICAL HOME RADIO COURSE at a rock bottom Price Our Kit is designed to train Radio amp Electronics Technicians making use of the most modern methods of home training You will learn radio theory construc tion Practice and Servicing THIS 1S A COMPLEFE RADIO COURSE IN EVERY DETAIL You will learn how to build radios using regular schematics how to wire and sotden in a Professional Manner how to service radios You will work with the standard type of Punched metal chassis as well as the latest development of Printed Circuit chassis You will learn the basic principles of radio you will Construct Study and work with RF and AF amplifiers and oscillators detectors rec
21. such as white or yellow to give the base and component parts a con trasting appearance Spray on at least three coats of paint and let it dry be tween each coat to produce a slick enamel appearance Let the wood base dry overnight before ak ae any parts Final Touchup After the bass ap pears dry mount the variable capacitor and connect two pieces of hookup wire from it to tie into the tube socket Next mount the small tube socket Temporarily place a piece of masking tape over the socket and wooden base plate Lay the base upside down over a shoebox to wire up the remaining components Feed the earphone cable through the rear hole and connect to terminals 4 and 6 of the tube socket Feed a short piece of hookup wire through the same hole to serve as an external antenna connection Solder this wire to terminal 2 Now solder the capacitor s two wires to terminals 2 and l Once again check over the en tire wiring procedure Solar Swinger should be ready to roll and rock Connect the antenna wire to the out side antenna or you can try to pick up local stations with a 12 ft piece of wire laying around the baseboard of a wall You should be able to pick up local 94 z stations at each end of the broadcast band If a ferrite adjustable antenna coil 1s used adjust the core until the stations are loudest at each end of the band Turn Solar Swinger s solar cell toward the sunlight or o
22. terminals soldered to the coil connect ing lugs Install the headphone jack J2 on the box front and the antenna ground jack Jl on the rear of the box as shown in the photos Cut a hole in the rear of the box for the battery leads and complete the wiring of the perf board with the interconnecting leads to the box components Install lugs on the battery leads to fit your battery terminals The leads on our model ex tended approximately 10 inches from the box but the lead lengths are net critical and can be any convenient length to fit your particular installatior To minimize accidental breakage the battery leads should be stranded wire preferably color coded red for posi tive and black for negative Testing Your Reflex For best results an outdoor antenna and a good ground should be connected to JI center con nector to the antenna and the outer shell to ground Inasmuch as the Re Hex Receiver project only uses a simple tuned circuit you may have some problems with overloading on strong local stations CI value can be changed to adjust the antenna loading small capacitance 3 to 20 pF for light load ing and better selectivity and larger capacitance 25 pF to 47 pF for heavier loading higher senstivity but lesser selectivity Before connecting up the receiver project to the battery check the wiring and then adjust the RF Gain control C7 to maximum capacity minimum The author used perfboard mounted
23. 1 30 150 for 1 30 100 tor 1 30 20 for 1 30 20 for 1 30 Sfor 1 30 Stor 1 30 40 for 1 30 20 for 1 30 Bior 1 30 10 for 1 36 4for 1 30 60 for 1 30 0 for 1 30 4 for 1 30 PL 259 2for 1 29 CAPEHART 99 1000 VOLT 2 49 COAX PLUG AM EM PHONO MINI RECTIFIERS Quick Eas ay ey crimping No 4 for 2 tor 40 Hes ere see athe 40 Soldering Strip insulation 1 30 STEREO RECEIVER 100 Prime with axial leads for squeeze Mates to SQO 239 For RG58 U 9 U Cat No 92CUSE96 Cat No 92CU2383 1000 s of hobby uses Good scund and contemporary design yh ie this HiFi argain Features incl slide control for VOL BAL rocker switch a for Powst ON OFF lllam Slide Rule Tuning and top mounted N a ceramic Phono with dust cover and Saphire cartridge 33 amp 45 Piv F A es RPM Also incl tleadphone jack and 45 spindle SIZE 14 x 5 x 25 AMP oz reg or 3 0 YOUR CHOICE 6 tor 1 29 Cat No 92CU5640A D 238 ys 100 2 25 2 26 1 SALE 12 for 1 30 ir a 200 2 95 2 96 s 1788 MICRO TOPHAT AED d 1942 MEO YELLOW STUBBY w PLUS SPEAKERS BRIDGE u 00 En he 41802 moro SINGLE PIM RED if D e800 4 95 4 06 27933 Amber if 2135 JUMBO RED l Same as above but incl dual marching speaker enclosures Ready RECTI FIERS 2199 JUMBO GREEN f to play SPKR SIZE 10 x 6 23 4 2 for 60 00 21 MICRO RED Cat Mo 92CUS640 Order We 2e 3 amp voltage
24. 1 AMP 200V MINI RECTIFIER 144003 epoxy axtel le 2379 woe b 29 4 3 SV SILVER OXIDE WATCH BATTERIES specify RW 1 18 32 or 100 120 z 063 1 29 3 LCD WATCH READOUTS 3 digits 7 seg dim OM x 1 6 50661 1 29 20 IC DICE CHIP complete circuitry saat sizes 73065 0 INSTRUMENT KNOBS asst styles and colors shaft 121 4 MIKE HOLDERS tor CB s and other mobile rigs 5634 5 TANTALUM ELECTROS TEARDROP style 2 2uf 259 205 2 INLINE FUSE HOLDERS complete w 5 amp fuss s 213 CFE ow aR Payers s 30 4 CABLE TIES non slip white plastic 05217 2 cc ecu cee eee ree Tae or 30pc HEAT SHRINK asst sizes 5OX shrinkage 9 248 Q 2 S L S 10W STUD ZENER DO caee z 5287 3048 EFEEFEFEFEFEFEFEEFEEERFEEFEFEPFERFEOGEREPEDPEPFEEESEPEPFEPEREPEFEFEEERI 24 for 4 30 20 for 1 30 30 for 1 30 Stor 1 30 8 for 1 30 Z lor 1 30 2 lor 1 30 Zfor 1 30 6 for 1 30 20 for 1 30 4for 1 30 6 for 1 30 2 tor 1 30 4 tor 1 30 ator 1 30 tor 1 30 20 tor 1 30 A2tor 1 30 100 for 1 30 12for 1 30 20 for 1 30 20 for 1 30 16 for 1 30 30 for 1 30 amp tor 1 30 2for 1 30 6 for 1 30 42 for 1 30 0 for 1 30 2 tor 1 30 20 for 1 30 20 for 1 30 20 for 1 30 2 for 1 30 100 for 1 30 20 for 1 30 4for 1 36 2for 1 30 100 for 1 30 24 for 1 30 120 tor 1 30 120 for 1 30 40 for 1 30 20 for 1 30 20 for 1 30 100 for 1 30 24 for 1 30 6 for 1 30 40 for 1 30 20 tor
25. 15 shipping and be prepaid EE 59 only 5 95 un 595 If youre going tolearn electronics you might as well learn it right Don t settle for less Especially when it comes to career training because everything else in your life may depend on it That s why you ought to pick CIE ELEMENTARY ELECTRONICS May June 1979 Youre probably seen ad vertisements from other electronics schools Maybe you think they re all the same They re not CIE is the largest indepen dent home study school in the world that specializes exclu sively in electronics Meet the Electronics Specialists When you pick an electronics school you re getting ready to invest some timc and money And your whole future depends on the educa tion you get in return That s why it makcs so much sensc to go with number onc with the specialists with CIE There s no such thing as bargain education If you talked with some of our graduates chances are you d finda lot of them shopped around for their training Not for the lowest priced but for the best They pretty much knew what was available when they picked CIE as number one We don t promise you the moon We do promise you a proven way to build valuable career skills The CIE faculty and staff are dedicated to that When you graduate your di ploma shows employers you know what you re about Today it s pretty hard to put a price on that
26. 1979 89 SYSTEM SHH BBA Big enought to utilize Full size eaters 10 woofer 5 middler amp 4 super tweeter Big enough to handle 50 Watts channel small enough to fit your budget Freq Resp 30 to 22 000 Hz Ferro Fiuid Damping Cabinet size 20x11x9 dp Good things come in Ismail packages a nice extra set for the E other room Sh Wt 60 Lbs allow for two 30 Lb parcels KIT Order No 8Y0542 88 88 pair PAF A G j P AT iff A f 16 8 WATI EO CEREO AAP Neat assembled board contains afl solid state components Contains a DARL INGTON drive push pull output all with complementary power tab tran sistors amp mounted to ig heat sinks Accepts input from tape decks mag netic or ceramic phono cartridges mikes etc Requires a 48V xformer amp 1 meg volume control not supplied Output 8 into 8 ohms supplied with data Sh Wt 1 Lb 8Y0513 5 78 Stereo Xformer 8G0530 S2 88 Stereo Pkg 16 watts W xformer amp Cont Sh Wt 4 Lbs 8E0544 TOUCH SWITCH ALARM NEW packaged system A super close out item Protects your valuables gun s CB s stereo equipment test equipment etc List Price 22 88 Sh Wt1Lb 8MI0474 3 for 22 88 8MI0474 _ 22 88 3 TOP QUALITY LO COST SPECIALS Order by Cat No and description Cat No Description DATA CASSETTES 10 min DISKETTE 5 soft sector T
27. 559 199 iv Tough Dog Propiems Solvea 252 p 199 u 5 95 580 Modern Radio Repaw Techniques 260 p 207 1 5 95 532 How io Repar Solid State Imporis 1929 81 1 122 amp 7 95 633 Piclonal Guide to Cotor TV Curcunt Troubles 256 p 262 il 484 TV Servicing Guidebook 176 p 1103 61 Jack Dari s Service Uire No 3 252 6 122 1 Jack Dart s Service Crime No 1 192p 125 Pinpon TV Troubles in 10 Minutes 327 p 394 TV Bench Servicing Techniques 2239 77 i Pinpoint Transisio Trouptes in 12 Minutes 492 p 243 1l 595 199 Coin TV Troudies amp Solusons 224 p 178 il 507 101 FV Troubies From Sympiom to Repay 224 p 170 il 619 T snnotingy Sold State Electy Powe Supplies 192 p 85 il 778 Smali Screen TV Servicing Manual 240 p 367 653 T shooting Sold State Wave Gen amp Shaping Cires 636 Installin TV amp FM Antennas 168 p 158 4 835 VHF UHF Fire Police H Scanners Ser Manual 250 p 6 95 625 Troubleshooting Solid Stale Amplihers 256 p 95 1 4 95 732 Jap Consumer Electr Ser ManuaitS6p incl schemanectoldoul 5 95 694 A lo Steren Service R Insialiavon 262 p 245 1 18 430 7 95 6 95 5 95 5 95 4 95 6 95 9951 5 773 Talk Back TV Two Way Cable Television 238 p amp 4 l 833 Complete Broadcast Antenna Handbook 448 p 3CB l 657 MATV Systems Handbook 176 p 91 523 Guide to Radio TV B cast Engineering Pract 288 p 140 1 733 Directional Broadcast Antennas 210 p 60 t 557 How To Become A Radio Disc Joc
28. 600 Photoelectric Lamp Switch Turns your lamp on at dusk off at daylight for that lived in look when you re away from home Learn To Service and Maintain Your Car s Efectrical System with this newest Heathkit Automotive Electrical Continuing Education Program Think of the money you ll save when you really understand how your car s elec trical system works and how you can service it This 4 part self learning program takes you through electrical principles starting and charging systems and accessories and body electrical all at your own pace and at lowest cost Super Coinshooter The GD 1190 is Heath s finest metal locator with adjustable discrimination and push button tuning that rejects junk and finds coins j L n a 5 For Treasure Hunters The Heathkit GD 348 finds buried metal objects with it s sophisticated induction balance system The tone from the built in speaker grows iouder as you pin point your find or you can use the front panel meter or optional headphones Learn How To Use Electronic Test Instruments with this new Heathkit self learning program A progressive 4 part program using Heath s famous programmed instruction with audio and visual aids for maximum efficiency Learn to use electronic meters oscilloscopes fre quency generators and special measuring instruments Build Your Own Custom Stereo And Get Heath Quality Plus Syste
29. 85 Digital Electronics Pnnciples amp Practice 292 p 191 il 105 Basic TV Course 224 p 128 it 111 Bas c Transistor Course 224 p 179 il CIRCUITS BOOKS HOBBY ELECTRONICS amp PROJECTS 1101 How To Design amp Build Your Own Custom TV Games 546 F 806 The Power Supply Handbook 420 p 292 l 1108 Lasers The Lighi Fantastic 294 p 158 l 1079 How to Build amp Use Low Cost Hydrophones 40 p 98 il 1113 Underslanding Electronics 182 p 2651 BOO Master Hdbk of 1001 Practical Electronic Circuits 602 p 1060 303 Dynamic Electronic Circuits 308 p 303 f 1023 Beginner s Gde to Designing Bid g lransistor Radios 140 p 965 Modern Transistor Radios 64 p 112 il 958 Beqinner s Guide to Making Electr Gadgets 140 p 113 il 921 The ABC Book of HI Fr Audio Prolects 168 p 131 l 909 How to Build Metal Treasure Locators 140 p 50 il 935 Build It Book of Optoelectronic Projects 238 p 175 il 30 Handbook of Semiconductors Circuits 444 p 317 l 964 Modern Crystal Radios Make and Use Series 64 p 101 l 637 Fun with Electronics 140 p 50 1 836 Optoelectronics Guidebook with Projects 196 p 115 l 905 Build It Book of Digitai Electronic Timepieces 294 p 209 926 Model Railroad Electronics 308 p 218 912 88 Practicat Op Amp Circuits You Can Build 40 p 120 1 B68 CBer s Handybook of Simple Hobby Projects 168 p 114 il 887 106 Easy Electr Projects beyond the transistor 224 p 790 21 Simple Transisto
30. An early spark tele 2090 80 diameter by a half inch thick The case was brass nickleplated and if the me ter had only one range it would have one short lead wire and a pointed con tact on the case Most Watch Case meters were made to test filament and B batteries used with the 1920 s bat tery radios I know of several collectors who collect the brass nickleplated me ters You can usually find these too at flea markets and garage sales A reprint of the Radiola III instruc tron booklet is now available along with the Radiola INA booklet that has been on sale for some timc You can get either booklet for 2 00 postpaid from Antique Radio Press P O Box 42 Rossville IN 46065 Safeguarding Your Collection I want to emphasize one more time the im portance of having a complete list of all your antique radio equipment put into a safe place not in your home I recommend a safety deposit box in a bank or similar institution I have writ ten on this subject before but ap parently most collectors don t want to do this Periodically I hear or read about a collector who was ripped off by a thief The latest happening I have heard about took place on the west coast There is a collector out there who had 13 000 vacuum tubes There were many tubes made between 1920 and 1930 some were made before 1920 and thousands were made after_1930 For tunately he had the foresight to call in
31. Better still simply use a coun ter such as the REDCO RFC 50 that has the sampler built in a counter spe cifically designed for in line connection to transmitters For full time indication of the car rier frequency of AM and CW signals f r SSB signals of sufficient output power so the counter can be triggered by the carrier leak thru or for the tune up carrier of SSB transmitters so equipped you just connect the trans CIRCLE 68 ON READER SERVICE COUPON ceiver or transmitter output to a UHF connector on the rear of the REDCO RFC 50 connect the transmission line to another UHF connector and key the transmitter The carrier frequency will be indicated by a six digit 0 3 inch LED readout Since the RFC 50 works off a minute sample of the power in the transmission line it can be left perma nently connected ready to indicate the transmitter s output frequency at all times Specifications The REDCO RFC 50 Communications Frequency Counter is housed in a 7 4 in by 8 in by 21 4 in cabinet It can be powered by 120 VAC or 13 8 VDC depending on which of two supplied power cords is plugged into a rear apron connector The switch ing from one power supply voltage to the other is done automatically by the plug on the power cord The rated frequency range is 500 Hz to 40 MHz through a direct connection via a front panel BNC connector Un like most hobby type counters with direct connection
32. Company Dept EE Box 465 Norwalk Ohio 44857 2 MONEYMAKING OPPORTUNITIES 250 00 profit thousand possible stuffing mailing envelopes Offer Rush stamped addressed envelope Universal ADVS X16180 Fort Lauderdale FL 33318 180 00 WEEKLY Malling Circulars Start im mediately Everready 422A Clermont Ave Brooklyn NY 11238 MAKE YOUR CLASSIFIED AD PAY Get How to Write A Classified Ad That Pulls Includes certifi cate worth 2 00 towards a classified ad in this publi cation Send 1 50 plus 25 for postage to R S Wayner Davis Publications Inc Dept CL 38 Lexington Ave New York NY 10017 WIN thousands Thoroughbred Harness Dog Se aA Free report Finish A Box 6226 Toledo 14 m 300 WEEKLY Home Mailing Program Details Thomas Dept D1 Box 11773 Charlotte NC 28220 MAILORDER GRAHAMCO 500 WEEKLY FANTASTIC HOME PROFITS DEALERS WANTED DPBX 99371 TACOMA WA 98499 AMAZING 265 000 Yearly with classified ads Free Proof Moneycraft 2316 Dale Ceres CA 95307 ee ee eS eee O HOW to get paid in advance stuffing envelopes Make a fortune doing it Details 1 00 Martin 3610 Toy Wisconsin Rapids WI 54494 350 WEEKLY Mailing Letters FREE Details Karmchell 628FD Cherry Albany GA 31701 YOU LL MAKE MONEY respondence MONEYMAKING OPPORTUNITIES Cont d EARN money addressing envelopes K G PUBLICA TIONS
33. DAK ML has a frequency response that is flat from 40cps to 14 500cps 3db Virtually all cassette recorders priced under 600 are flat from 40cps to about 12 000cps so we have over 2000cps to spare and you ll probably never know the difference No apology We feel that we have equalled or exceeded the mechanical reliability of virtually all cassettes and offer one of the best frequency re sponses in the industry Maxell UDXL is truly the Rolls Royce of the industry and DAK is the 100 US made Cadillac or Corvette Price DAK manufactures the tape we sell you avoid paying distributor and retailer mark ups While Maxell UDXL 90s may sell for 3 50 to 4 50 each DAK ML90s sell factory direct to you for only 2 19 each YOU WIN You are paying less for the 10 90 minute cassettes than you would pay for the bribes we are offering if you went to a Radio Shack Store Yours Free CHECK THE VALUE OF THE BRIBES AT RADIO SHACK Think of it 10 six foot hook up cords with RCA plugs at each end Whether you use the cords now or when you buy new equipment those of us who are tape recorder nuts never seem to have enough Radio Shack sells six foot cords for 1 89 each You will find dozens of uses for this deluxe battery eliminator AC adaptor around your home or office 4 voltages 3 4 5 6 and 9 volts 4 plugs will fit virtually any calculator radio or battery operated recorder we have seen You ll save a lo
34. ELECTRONICS May June 1979 Now we will put both of the circuits together Note that we have two batteries one in each of the base and collector circuits When both the base and the collector circuits as in the diagram above are connected it demonstrates the outstanding characteristic of the transistor which is sometimes called transistor action If base current flows in a transistor collector current will also flow Examine the current paths in the diagram below Base current Ib flows through the base emitter diode and causes the collector current ic to flow through the base collector diode No current flows from the collector to the base as shown by the dotted line below The reason why the collector current takes the path shown in the first of these two diagrams rather than the dotted line path is beyond the scope of this book This is the domain of semiconductor physics and is not needed in electronic circuit design and analysis at this time Up to now we have been using the NPN transistor solely for the purposes of illustration A PNP transistor could have been used There is no difference in how the two types work or behave What is said about one is equally true for the other There is however one important circuit difference which is illustrated below This is caused by the fact that the PNP is made with the diodes in the reverse di rection from the NPN Note how the battery polarity is reversed and
35. Eleven keyboard switches for channel selection and _ control Standard accessories include a microphone mobile mount DC power cable Receiver Section Test Input sensitivity 0 3 aV Adjacent channel rejection 56 dB AGC action l W 1 13 dB Input level for S9 meter indication 80 aV Transmitter Section Test AM RF output _ 3 6 watts Modulation to 85 Relative sensitivity for 85 mod ae 31 dB Modulation limited to 100 yes Editorial Remarks The Key Com 1000 has a 5 dB per unit S meter double conversion jacks for P A and remote speakers L E D digital channel indicator on board micro processor providing 40 channel 10 channel memory SCAN alternate channel operation and SCAN 10 second check of priority channel S RF output meter and separate power connection for mi croprocessor memory E ELEMENTARY ELECTRONICS May June 1979 322 new 20 page full color TRS 80 Microcom puter Catalog has just been issued by Radio Sheck The catalog includes complete current information on the TRS 80 Microcomputer its peripherals and accessories with plain language descriptions ap plication ideas and detailed specifications z 386 If you re lookng for books on computers calcu jators and games then get BITS Inc Catalog It includes novel items 335 The latest edition of the TAB BOOKS catalog describes over 450 books
36. LBO 507 a 20 MHz trig gered scope is designed for broad use in industry hobby laboratory and ser vice The LBO 507 offers automatic triggered circuitry to assure maximum adjust ments as well as a trigger sensitivity range It over the entire operational CIRCLE 72 ON READER SERVICE COUPON provides convenience of pushbutton switch selection for every functional de mand 10 mV cm vertical sensitivity calibrated in 11 steps in a 1 2 5 se quence up to 50 V cm with variance control and a 17 5 nanosecond rise time Bandwidth is DC to 20 MHz Sweep speed for the LBO 507 is 0 5 uSec cm 18 steps in a 1 2 5 sequence up to 500 mS cm with variable control The LBO complete with low capacitance probe and terminal adapter Get the complete specs 507 is priced at less than 500 and is direct from Leader by writing to Leader Instruments Corp 151 Dupont St Plainview NY 11803 3 Digit DVOM The new 3 digit Mode 3300 digital VOM just introduced by the Triplett Corp features an extra visible 3 in high digital LED readout display with Polarity ndica CIRCLE 7 ON READER SERVICE COUPON tion 5 accuracy and low power ohms readings The five function 22 range Model 3300 offers complete portability with precision measurement capability 17 NEW TRON EX F 1 9 LENS featured in November Popular Science or TV rv not inciuded urs kills required E ORDERS any portable i ho ilt
37. LISTING Opcode Operand Comment LXI H 200040 Put address in H amp L MVI B 005 Put amp in register B x MVI A og Put 2 in register ADD B AddBtoA MOVM A Put A into mem ory location HLT Halt This is an assembler source code listing for our addition program The assembler reads the letters and numbers and then translates them into binary numbers mans with short abbreviations called mnemonics Mnemonics apply only to instructions in the instruction set and numeric data must be represented for humans by another form of notation than binary usually octal base 8 or hexadecimal base 16 We won t dis cuss these here however and I will use decimal notation to indicate numbers the computer must deal with Remember that each 8 bit byte of code above resides in a separate loca tion in memory and that each such lo cation is specified by a unique address For the 8080 addresses can be num bered from 0 to 65 535 decimal If we were to translate this program into readable form we could see that it is telling the CPU to first load the H and L registers with the numbers in the next two memory locations The first goes into the L register and the second into the H register this reverse order is an 8080 convention and not true for all CPU s This number will later be used by the computer to refer to an address elsewhere in memory The next instruction not the next byte is at address number 4
38. Ontario L8N 3P9 Antenna incorporated International Division PO Box 1002 Rockville Centre New York 11571 CIRCLE 24 ON READER SERVICE COUPON These features will persuade you The Persuader Antenna is Your Best Antenna Choice 60 Stainless Steel Tapered Whip and No Spring The super long whip increases the aperture of the antenna This increases e the signa capture area on reception e the transmit signal and radiation intensity at the horizon e bandwidth to well over a 40 channel capability The 125 diameter whip is tapered so shock is distributed evenly There s no spring to stretch break or bend the whip away from the straightest possible upright position Exclusive coil in cup design Loading of most low profile antennas is by a simple printed circuit board that can t be tuned and will eventually burn out These new Persuader anten nas are completely pre assembled and pre tuned and feature an actual hand wound hand tuned copper wire loading coil tested with 500 watts rated at 100 watts continuous It s even more effi cient than our base loaded coils because it s wound to a larger diameter with fewer turns This unique design also involves fewer mechani cal and electrical connectors fewer resistive con tacts between loading coil and cable termina tions less chance for dust moisture or road gunk to contaminate the contacts This concept has been field tested by thousands of CBers in
39. Tube Voltmeters oscilloscopes etc I have built from scratch and from kits of parts i e Heathkits and Eico kits Most collectors aren t interested in test equipment either because it ts hard to find is too expensive or they aren t interested in electronic repairing of their own equipment At the ARCA conference in King of Prussid PA sev eral collectors had test equipment for sale at very reasonable prices I saw several tube testers made in the early 30 s These testers would check 201A s 199 s etc which all collectors use There were also individual test meters priced as low as 50 each which still worked well and only needed cosmetic repairs In my stock I probably have more than 350 meters ranging in age from the 1920 s to the 1960 s If you arc interested the old brands to look for are Hoyt Jewell Weston Sterling Beede and Readrite These meters were t the more popular ones made for radio use Other meters made for electrical and automotive use were Roller Smith Westinghouse General Electric and Splitdorf The above named meters are the ones to look for in flea markets and garage sales Another group of meters were called pocket meters or Watch Case meters and were intended for home use This type meter was usually 2 inches in graph transmitter also entered in the old equipment contest at AWA Conference The Rolling pin shaped glass tube holds the spark gap apparatus
40. WNETV LNdNI ee OSI 2109 1 N7Z TINYN WIANN G3LISIT LSILHY ON INI Ud 3 ST NIHL 12X di 9202 DLE SOF INOS LNIHd 0902 N3H I aab dI SS e N3HL ww tE dI wiz 8292 JLIE S e OLODP1 XK N V dI AL SNSI SE SY IF AVIU s AWOLSAY B X EN LSILHV 39 INWYN a LNdNI gor ILIE GSI OL10910 d 9 d 3I 4f 3rf QIQ16 INIUd OTOl NAHL G dI ocol ILIE 3 4 SH T1t Y Fd SNIdOOT NOTLIJJYUOIJ YOUNT YO4d GISN JUV 4 ANY I A NIE i 9 EN0S LAdNI x y a WNely LAdNI gc0o DIOS aasa E i Sul N3H L oD HHI lt gt S V 31 ozar 0109 9ad JAYIT U S3Ttsyer LSILuyy LM dN I INI ud LNIHd Ot 310 LSA adw LUYIS LIXZ OL ZAVAT JdALs INT Ud a ONOS ONY WNATY LSI LYUVY USING LINIHd LINIHd STI 9195 wAYVHDOUd IAVIT OL LIX3 INIHd aC LYYLS JIS LSIT OL AAY OL JLivddn INIYd SITI TIY 30 ONILSIT TL13TdWO09 HO4 LSIT LINIHd DNOS AM NAETY ONY LSILMV 3192971 OL SONOS INTud NASTY AG LSILHV 3192971 OL W ngTV INIHd wLSILSY AG ONOS ANY NWNNGTY 319201 OL LSTLUV INTUd SIIHINI YLYGA TVILINI YILINI OL LUVLSa LNIHd ar w w w w ee rae ee ae LNIYA 3 _ wNOITLON AS ANUWHOD LNIYd 4 INIYd INI Ud i 20897 AR0S ABAY JABE JAZ 00901 ILOS X NI SI 0109 ONYWHOJ TVWITITI LNIHd X Lx3N Z NZHL 2 T dI T avau J 9 OL tex W4 GNZ 1 103S012 wLIXa 2S9 dI 3Su0 LS4qu t2 GNVHH802 LR dNI LNIHd Qt IW LSY P Safa WAGTY LNIUd ss 2 gS BY S
41. aboard America s new space shuttle the Enterprise a new material is solv ing many heretofore hard to handle heat problems protecting vital cables wires meshes tubes and hoses in high temperature environments And a World War II uniform company is fabricating the product In addition to protecting materials against temperatures up to 2 600 degrees F for ex tended periods of time SF2600 braided ceramic sleeving offers short term protec tion up to 3 000 degrees F The sleeving retains its strength at elevated temperatures This space age insulating material 3M Ceramic Fibers is being fabricated in the form of protective sleeving by Santa Fe Textiles Inc Santa Ana Cali fornia Specific applications for this new insulation which Santa Fe calls SF2600 include protecting cables from open flames and shielding thermocouple wires as they measure the heat in ovens In addition the sleeves protect hoses from molten metals in steel plants guard fire control systems insulate fur nace components to cut down on heat loss and serve as the sleeving over wire mesh for gaskets on the Enterprise In the home braided ceramic sleev ing can be used as a gasket around the doors of self cleaning ovens This ma terial also is being used to insulate heaters hair dryers coffee makers and other home appliances Adding Memory With a Laser A new approach to storing data in computers using a tunable dye laser is describ
42. approved at the Seventh day Adventist annual council in Washing ton D C last October That program to begin also in 1979 though probably not to be completed this year calls for four shortwave transmitters to be lo cated at a site in Liberia West Africa The AWR international transmitters will be one of 250 kilowatts two of 100 kilowatts and a single 50 000 watt SW unit A medium wave station will serve local Liberian audiences DX Programs Ambrosio Wang An Po DX editor of Radio Exterior de Espana in Madrid Spain whom a num ber of North American DXers had the opportunity to meet at the Association of North American Radio Clubs ANARC convention sponsored by Radio Canada International in Mont real last summer recently announced an expanded DX program Radio Exterior de Espana s DX pro grams from Madrid will include he notes announcements about the most important news of other stations with DX programs such as changes in times and frequencies new services contests and meetings or anniversaries The station s DX program in English is at this writing aired every Sunday 2115 to 2130 GMT and is repeated an hour later on 6 100 7 275 9 505 and ELEMENTARY ELECTRONICS May June 1979 BEARCAT SCANNERS ANNOUNCE AMERICA S ONLY 50 CHANNEL MICRO PROCESSOR CONTROLLED SCANNER IT SEARCHES STORES REMEMBERS AND ALL BUT THINKS FOR YOU The new Bearcat 250 Bearcat s new 250 Is fully synthes
43. box and the timer you re ready for the safest driv ing you ve ever done Consult the table for the proper setting for the road con ditions and the prevailing speed of traf fic The look ahead feature of switch S3 allows you to set a considerably greater safety margin for conservative driving You may wish to clip the ta ble from the page and fasten it to the underside of your sun visor where it will be handy when you need it Re member The Space Cushion Timer will not prevent accidents if you don t use it and even when you do use it it s not intended as a substitute for seat belts and common sense u 52 SPACE CUSHION TIMER DRIVING CONDITIONS NORMAL POOR While almost any case can be used for the space cushion timer this Radio Shack clock case seems ideal This unit can be mounted at almost any convenient spot on the dash board of your car Rationale For Two Seconds Following Distance At 1 Car Length For Each 10 M P H You Will Be based on 20 ft Feet Car Will Travel In 1 Second 44 4 58 6 73 3 1 88 0 1 Got parts problems Solve em TO CAR S 12 VDC SUPPLY ZI TOUCHPLATE 2 Second Safety Rule You Will Be 88 8 ft back 117 2 ft back 146 6 ft back 176 0 ft back vehicle 60 ft back 80 ft back 00 ft back 20 ft back with Hobby Mart page 89 QI 2N3398 PARTS LIST FOR SPACE CUSHION TIMER C1 2 2 uF tantalum capacitor 25 volt or
44. channel number greater than 40 or a three digit number the computer auto matically reverts to channel 19 Channel programming for both the memory and monitor modes is volatile meaning it vanishes when the power is turned off If you want to retain the programming simply turn the volume control down but not off Once the memory is lost it has to be repro grammed Performance As far as the TERES is concerned you get everything that s claimed It works well and certainly provides a convenient way to keep up with all 40 channel action There are x a few operating or programming hang ups that takes some practice to unravel but they are just about what you ll find on an ordinary VHF scanner Basically there are no hang ups once you get used to the programming procedure As for the receiver and transmitter performance is what I ve come to ex pect from the better quality transceiv ers The receiver sensitivity measured 0 4 V for a 10 dB S N N signal plus noise to noise ratio siderably better than the factory claimed 50 dB while the AGC action was a superb 3 dB between the test limits of 2 aV and 10 000 aV The transmitter delivered srati 4 watts output to a 50 ohm load A 30 dB microphone sensitivity produced 100 modulation which was limited to 100 The S meter was calibrated for an S9 indication with a 100 aV input IAIL in all an impressive package which is probably representative of t
45. commercial set NRI instructor engineers have de signed this television so each step of construction is a learning experience As you build it you perform meaningful experiments You see what makes each circuit work what it does how it interacts with other circuits You even introduce defects troubleshoot and correct them as you would in actual practice And you end up with a mag nificent big picture TV with advanced features One you can sell or use in your home Also Build Stereo Test Instruments That s just a start You dem onstrate basic principles and circuits on the unique NRI Discovery Lab then apply them as you assemble a fine AM FM stereo receiver complete with speakers You also get practical experi ence as you build your own test instru ments including a 5 triggered sweep oscilloscope CMOS digital frequency counter color bar generator and transis torized volt ohm meter Use them for learning use them for earning as a full or part time TV audio and video systems technician Complete Effective Training Includes Video Systems Using NRI s exclusive methods you learn far more than TV servicing You ll be prepared to work with stereo systems car radios record and tape players transistor radios short wave re ceivers PA systems musical instrument amplifiers electronic TV games even video tape recorders and tape or disc video players Your training covers just about every kind of
46. dering iron against each prong Let the excess solder begin to boil and then fling the tube base downward and the excess solder will fail into the bottom of the pasteboard box Use this method on each tube prong a couple of times to remove all of the solder After the excess solder has been removed pull the connecting wires out of the tube base area You may have to break the glass in several pieces to remove some stubborn connections Clean out the excess glass cement with a pocket knife and place the tube base with the glass envelope for safe keeping Tube Base Construction Cut four pieces three inches long of number 14 or smaller copper wire These four sup port wires will become tie in circuit and mounting supports for the small components You may use any stiff wire for these supports as long as the wire itself can be soldered Number 14 copper wire will just fit inside the tube pins and solder should be fed up from the bottom terminal Also you may solder the wire supports from the top side down inside the tube base Place support wires in terminals 1 2 6 and 8 Look at the bottom of the bake lite socket and start with Pin 1 to the ELEMENTARY ELECTRONICS May June 1979 left of the center pin Although the tube locator pin is broken ofl you still can see where it was located After all support wires are soldered Into position clean excess solder from each wire with a pocket knife Scrape off rosin and excess so
47. discontinuity in the siding such as a fiberglass or shingle front good to excellent reception was attained though nulling in some di rections was not sufficiently deep Fur was partially below ground with the sidirfg starting above the basement ceil ing actually 3 feet above ground was very good The equipment at the time this ar ticle was prepared was available di rectly from Palomar Engineers 455 Escondido CA 92025 The loop amplifier is priced at 67 50 less 2U6 type 9 volt battery Plug in loops are priced at 47 50 each Make certain you specify the BCB antenna for 550 1600 kHz coverage Add 2 shipping and handling for U S and Carfada to total order For additional informa tion circle No 52 on the reader s ser if Box ance and it might be necessary to po ther reception in a basement which vice coupon a 4 What is meant by the term current gain What sym bol is used for this What is its algebraic formula Basic Course Continued from page 84 5 In the figure in question 2 Rb 27 kn and Vs 3 V tered and their similarity to a mechanical switch is SRO RSS SP ee ei 4 made use of in many digital situations We will not get 6 Repeat question 5 with Rb 220 kn and Vs 10 V into the details of digital electronics in this book beyond soe TLV MIDE Wie Bs eee a Oia ee a examining the simple transistor switch _in the next 7 Using the
48. etc the victory will be less clear cut Even if an image doesn t cause inter ference it can as noted at the beginning of this article lead you to report a sta tion on a false frequency Any time you hear a broadcast station about 910 kHz below a regular shortwave broadcast band see our chart check that band _ to make sure you can t find this same station with an even stronger signal A station will always be strongest on its real frequency Overload Sometimes signals will come in so strongly that a sensitive re ceiver cannot handle them Under these circumstances mixing will take place independent of the local oscillator that hypothetical case of WWV 2500 and VOA Greenville 6190 producing images of 8690 and 3690 kHz That 9200 3400 rn 3800 4000 4750 5060 5950 5200 7100 7300 95009775 The Shortwave Broadcast Bands Shared with utilities Shared with amateurs i you hear a broadcast station approxi mately 910 kHz below one of these bands it may be an image The frequencies listed on the chart shown above are in kiloHertz sort of extreme frequency spread usu ally occurs only with standard AM sta tions if you lived in New York City you might find WQXR 1560 mixing with WMCA 570 on 990 1560 minus 570 and 2130 1560 plus 570 ar i even then it may mean that small amounts of unwanted direct current are getting into the RF circuit see block diagram
49. found that needed restoration had defective cabinets The speaker grill and grill cloth are the most likely items to be damaged There is usually veneer coming off in several places I even have a radio whose front has come loose from the sides To get back to the letters it seems like a good idea to set up a system to find chassis for these cabinets The Philco cabinet had no model number but from the drawing he sent I believe it to be a model 33B or an 84B The only infor mation I have on the Sears cabinet ts that it is Beehive or Cathedral shaped If any reader has a chassis or speaker to fit either cabinet and he writes to me in care of ELEMENTARY ELECTRONICS magazine I will pass the information on to the cabinet owners I just received word that Antique Radio Press will no longer publish An tique Radio Topics After January 1 1979 it will be published by Puett Elec tronics P O Box 28572 Dallas TX 75228 If you are interested in sub scribing or want a sample copy write to Puett Electronics i Parts for Sale Antique Radio Parts P O Box 42 Rossville IN 46065 will publish two antique radio parts catalogs in 1979 The catalog will list tubes parts and services available to collec tors of old radios and wireless equip ment To receive both catalogs send 25 in coin plus two long self ad dressed envelopes to the above address If you live outside the United States send International reply coupons or 40
50. from complete and exphcit lesson materials with additional assistance from our home study instructors Advance as fast as you wish but take all the time you need to master each topic The Grantham electronics degree pro gram begins with basics leads first to the A S E T degree and then to the B S E T degree Our free bulletin gives complete details of the program itself the degrees awarded the requirements for each degree and how to enroll We are located at 2500 S LaCienega BI Los Angeles Calif Write to our mailing address shown below for Bulletin G 79 Grantham College of Engineering P O Box 35499 Los Angeles California 90035 Worldwide Career Training thru Home Study 16 CIRCLE 11 ON READER SERVICE COUPON HEY LOOK ME OVER Continued from page 14 Oscilloscope Kit A new low cost DC to 5 MHz Dual Trace Oscilloscope kit the Heathkit 10 4205 features a vertical input sensitivity of 10 mV cm a stable triggering circuit for solid waveform displays seven calibrated time bases from 200 mS cm to 0 2 uS cm a regulated vertical amplifi r and horizontal sweep circuit power sup plies Other IO 4205 features include a partial mu metal shield an extra bright 5 inch flat screen CRT and a lightweight durable cabinet with flush mounted han die for easy carrying and stackability with other instruments All controls and CIRCLE 1 ON READER SERVICE COUPON inputs are front panel mounted for sim
51. give RF interference but my Pixie verter doesn t seem to cause problems However the compu ter itself does cause considerable inter ference which I believe is from the power supply even though it is shielded and well grounded For this reason it is best to keep both your monitor and cassette as far from the computer as practical The chassis is of very heavy grade metal and sturdy As I mentioned be fore I used this as a grounded work surface However I feel that the solid walnut ends should be optional I don t know the current price of walnut but BAUD RATE I6K RAM BOARD DIP SWITCHES DIAGNOSTIC SOCKET Sarpy i SERIAL PARALLEL I O PORTS I would have preferred to have seen the money going for more hardware or a larger version of BASIC The backplane board is the equiva lent of a motherboard but has only 5 slots This does not present quite the hardship it sounds as the VDM mod ule and all I O circuitry are on the main PC board and do not require space Sockets are included for all five slots and a diagnostic socket is used on the top of the backplane board and can be used either as a sixth socket or for an extender board Unfortunately their diagnostic socket is not the same quality as the other sockets Mounting the backplane on the chassis was not an easy job and it is necessary to remove it if you want to remove the main PC board for ser vicing Perhaps Processor Technology s design
52. however the input is not the usual 1 megohm it is 50 ohms with back to back diodes across the load resistor providing protection against excessive input voltage Two UHF connectors on the rear apron provide an RF sample from a trans mission line for the counter input Operation A resolution switch on the front panel positions the decimal point and provides the proper gate time for direct indication of MHz and kHz It also serves as the power on off switch Resoultion is 10 Hz meaning that in any frequency reading the last place is not indidcated For example 195 599 kHz is indicated as 0195 59 with the resolution selector at the 10 setting meaning that you should multiply the reading by 10 0195 59 times 10 be comes 195 590 kHz In another ex Continued on page 88 ELEMENTARY ELECTRONICS May June 1979 OST OF US WHO DRIVE the highways M these days have become witness at one time or another to the gruesome sight of a high speed rear end collision With today s cars becoming smaller and lighter the only way the auto makers can provide a margin of col lision safety for the occupants is to design the cars to crumple on impact thus absorbing the shock and hope fully leaving the passengers uninjured Separate the template for the touchplate and make an individual printed circuit board for it Make both PC boards very carefully ko EPELE a w The drawback to this method is that while
53. juNowe y 3 onp i Ajdieys am gyep payuemun Jo uon p PUB uor 591103 10113 2AN123 9s u oq 3 eu TUS OM JE ng wemoid rolu Aui ysip e q p rmb i Ajjewiou AloWwsW Jo Junowe 3y PIOye uevd sjstAqqoy 1 1nd wod sn jo AueW MON Wyy Sse O0 GAT WoDOsed y se_yons wi9 sAs Bunei do umo sr 10 ATOW SU Je UOI Ippe ou s imb r y rym waysks ysIp e Suisn usyM U 9A3 WYYy oww Jajndwos snowJous AH18 91I Ss rmb s Wi UONIIIIOD 10119 3AH 29 9S pue 3Suncp dn gep J10 smojyje juswaZueIIe siy SUM ASIP Y 0 Joeq p n usuen sr 34 8gp Mou y Udy pue p ss sor d pue p je nd uguu A1owaul s a jndwos y Oju Udy e SI YSIP dy Wor gep y Je yey Ul Suu 3 s S YSIP dAlIp a suls JOJ puUly s Jo yeotdA s ureidoid u L EA311 31 Sg pue JTeIOYS p Ep JAISSEW 103 pasn st tu3 s S ysIp MOY p m moys M ALO UIAUT WVADOUd S ANSSI LSVT NHVZ8A uguipeoliq AueyAq N DISNW ANOA JO 329811 d y O0 AJO USAU AJOLUSBLU MOj SIU SN JOLA AAS l ELEMENTARY ELECTRONICS May June 1979 SJRUILUISY LYO JSOW UO s u i OM 40 ALL BUI BUIS P JIM 1nolutid 1 pio2 1 822 xaldiyjnw jeuoneN e pue ALL E HSV ue euluual LYO T LOV Wa O1DIW e ArOWalW YZI UMA 4ayndwosd 0089 diMS Buisn passnqap pue paydayd BIE ULWINIJOD SI 10 SLUBIBOJg S19181d1 1u DISVG 413470 YUM VSN JO UO iJipouu awos asinbas 443i pue seq Y8 O Z d diMS u U HUM
54. laid out There are a number of slots for additional memory boards The power supply is behind the mon itor output jack and cooling fan OUTPUT TO ee MONITOR with the power supply plugged in pro vided a good grounded work surface and the fan kept the solder fumes away Here is where I encountered the nec essity of a good oscilloscope The clock and VDM circuits both passed their tests on my VOM but the VDM re fused to work A shorted disc capacitor in the clock circuit proved to be the culprit but this could only be traced by examing the waveforms Also the value of resistor number 80 had to be de creased to 270 ohms to increase the sync amplitude on the video output to enable it to be displayed Interfacing I used a Pixie verter to interface to an old T V I chose this method mainly because it was cheap but it also allows me to attach the computer to another T V without dif ficuly Furthermore most old TVs the ones favored by hobbyists lack schematics and have hot chassis which makes patching one s computer directly to the video amplifier circuit rather hazardous both to man and machine I also tried the Waterloo Modulator featured in the January 1978 issue of Byte This uses a 7413 to create an oscillator but the display was not as sharp Another possibility l considered was a UHF modulator but most old TVs don t have UHF tuners Theoretically a UHF modula tor would not
55. let us assume that our addition program has either been entered in machine language by a pro grammer or been translated by a com piler At any rate it now resides in memory as absolute machine code the stuff our CPU can digest Also for our purposes we will not use a terminal input output can really get compli cated and assume that the two num bers to be added are contained in the program Instruction While there are perhaps more elegant and efficient ways to write this program it will serve to illustrate some of the things the computer does To the CPU our program would look like this 00100001 10000000 00100000 000001 10 00000101 00111110 00000010 10000000 01110111 10 01110110 e 1 2 3 4 8 6 7 8 This is of course incomprehensible to a human reader especially since practical programs are many hundreds of times longer than this For this rea son those Bytes which are instructions and not data can be described by hu COUNTER 0000000000001000 INSTRUCTION REGISTER a CONTROLLER A 00000010 B 00000101 ECCE H 00100000 78 _xxxxxxxx jc xXXXXXXX J Here the status of the 8080 CPU is shown with the program counter ready to load the instruction that is contained in address 8 into the instruction register Note that the program counter con tains the address of the next instruction CLOCK REGISTERS 10000000 L Figure 3 T ASSEMBLER SOURCE
56. military or indus trial surplus speaker kits TV games computer terminals tools TV components lenses and more 364 If you re a component buyer or specifier you ll want this catalog of surplus bargains industrial military and commercial electronic parts all from Allied Action 365 Electronic Supermarket has a new cCatalog of almost everything in the field transformers semi conductors tv parts stereos speakers P C boards phones wire and cable tools motors 366 How about a hybrid 13 watt audio module for 8 88 Or ultrasonic transducer for 1 49 You find these and other exotic parts and products aplenty in Poly Paks flyer Get your copy now 375 Compucolor Corp has a personal computer system with an 8 color integra display a type writer like keyboard and a mass Storage device Programs are ideal for checkbook and income tax figuring 377 We can t enumerate all the products in John Meshna Jr s catalog of surplus electronic parts power supplies computer keyboards kits for alarms clocks speakers and more 378 Delta Electronics is a complete parts source for electronics experimenters Discrete parts mod ules boards subassemblies and complete gadgets Get Delta s 120 page catalog today ELEMENTARY ELECTRONICS Box 1849 G P O New York NY 10001 _ Please arrange to have the literature whose numbers have circled below sent to me as soon as possible am enclosing 50 tor each grou
57. more than just the do it yourself angle it s also the spirit of adventure In this pre packaged deodorized world building your own stereo system shortwave receiver darkroom timer or CB outfit is like constructing a fine tuned little universe all your own And when it all works perfectly it really takes you to another world ELEMENTARY ELECTRONICS knows the kinds of projects you like and we bring em to you by the truckload Ever hanker to build a sharp looking digital clock radio Or to hook up an electronic game to your TV Oran dasy to build photometer that makes perfect picture enlargements Or a space age Lite Com so you and the family can talk to each other on a light beam We ve got it all to get you started WHEN IT COMES TO REPAIRS E E can save you time trouble and a pile of money Has your sound system gone blooey just when the party s going great Do you shudder when your friendly neigh borhood electrician hands you the bill E E can help Of course we can t make you a master electrician overnight But we can show you the fundamentals of repair plus maintenance tips IF YOU RE NEW TO ELECTRONICS YOU GET A BASIC COURSE That s right It s a regular feature And Get switched on eB prentary JElectronics it gives you the complete ground floor lowdown on a variety of important electronics subjects For example Understanding Transistors How Radio Rece
58. normally open relay contacts will close and the LED will light si multaneously These two conditions will persist as long as the SCR remains latched Note how switch S3 selects either the normally open N O or normally closed N C contacts of K1 This al lows a load to be turned on or off respectively when the circuit is acti vated Diode D1 connected across K1 s coil is normally reverse biased not conducting When the SCR is forced to unlatch however K1 s coil gen erates an inductive kickback voltage which could cause trouble if D1 were not there to clip it In order to see how unlatching is accomplished let s assume that the SCR in the module is initially unlatch ed and that mode switch S2 is closed in its pulse position Since the SCR is not conducting the Voltage at the green lead of the module must be high about 7 volts above ground This potential drives sufficient current through R3 D2 and D3 into the base of transistor Q2 to ensure that Q2 s col lector is conducting current heavily This prevents the voltage on C3 from rising and nothing of interest happens Suppose however that a sound trig gers the module into conduction The 36 1 RELAY CONTACTS COMMON 4 a NORMALLY OPEN r a NORMALLY CLOSED GREEN This is the component side view of the main printed circuit board The foil pattern is on the reverse side If your K1 relay has
59. of 285 00 Sony is giving everyone a chance for 4 400 to be the first on their block to have a pulse code modulation digital audio processor It is said to virtually eliminate tape hiss distortion and wow and flutter and to provide 85 dB of dynamic range with the peaks clearly recorded Fok more information circle 61 on the reader service coupon Heath is offering a new 125 watt per channel rack mounting power amplifier kit with a mail order price of 359 95 Model AA 1600 An optional oak finished case is available for 27 95 Circle number 1 2 Sansui claims to have the fastest re sponding preamplifier model CA F1 in the west and east with a 50 V uSec slew rate and 0 06 Sec rise time The aux tuner and tape inputs are claimed to have a 5 to 600 000 Hz frequency response and a 100 dB signal to noise _ ratio 495 Circle number 57 for more information about the CA FI1 J There are programs called assemblers which allow one to write a program using the written mnemonics and num bers The assembler then redtis this written program called a source listing and translates the letters and numbers into the binary information for direct use by the computer An assembler code source listing of our addition pro gram would look like that in figure 3 When this is read by the assembler the comments are ignored and every thing else is translated into the binary code as shown abo
60. off switch obviating removal of the bat tery when it s not in use Circle 74 on Reader Service Coupon duce a noise having a constant pitch and intensity This was put in the kitch en of a ranch style house situated on one acre of real estate Each mike was first carefully tuned to the selected FM frequency usually about 108 MHz by simply turning a small tuning coil with screwdriver or alignment tool until the nearby radio squealed Each microphone was then placed in the same position near the noise making timer while the output signal was mon itored throughout the house and out of doors with the portable radio Warning the tuning coils in the mikes are very delicate and will absolutely not take heavy handed abuse Heed manufacturer warnings about using a light touch and against playing with the coils unnecessarily In the following summaries we ll first provide pertinent manufacturer in formation and then add our own test observations Micro FM Wireless Mike MLI In dustries 19 95 plus 1 50 postage and handling is the smallest of the fac tory built microphones measuring only 1 inches by inches by inches less than one cubic inch yet it has one of the longest transmission ranges The manufacturer says the range is up to 100 feet indoors and 300 feet out doors The tough aluminum case is black anodized for durability and the 1 3 volt mercury battery included in the purchase price is claimed to
61. on a plastic box as chassis for the sig nal snare Push in solder terminals make construction a a snap The input r output jacks are all mounted on box j under the board e eta as s teases eees l lt o gt e 9 s lt e ese Sade Heese ot of oe tne Oe amp eee 4 tee gt oma LA 8 4 s Sees l PEDO ee RS ECO io CS Fe OW SIO LS Zid TS V T RE Gain Set the volume control R2 full counter clockwise for minimum audio gain Check the lead polarity before connecting the 6 volt battery to the receiver then plug in the head phones 2000 ohm type Tune the broadcast band with C3 while adjusting R2 for a comfortable audio volume Adjust LL for best band coverage for your particular location QI HEP FOQIS PARTS LIST FOR CNE TRANSISTOR REFLEX RECEIVER C1 47 pF ceramic disc capacitor 15 volts C2 10 0 0022 uF ceramic disc capacitor 15 volts C3 355 pF variable capacitor C4 0 1 uF ceramic disc capacitor 15 volts C5 C3 470 pF mica capacitor 15 volts C7 2 to 25 pF mica trimmer capacitor C8 5 uF electrolytic capacitor 15 volts C9 0 001 uF ceramic disc capacitor 15 volts C11 100 uF electrolytic capacitor 15 volts 01 1N34A germanium diode or equiv Ji Prono jack RCA type for Ant and Gnd connector ELEMENTARY ELECTRON
62. our Model 13503 shorter whip plain white cup Your good buddies will tell you every thing we say about it is true Available with Trunk Lip or Magnet Mount for performance e SWR of 1 5 1 or less across all 40 AM and SSB channels e Shunt fed loading coil is DC grounded for quiet performance bleeds off static from rain snow air particles Performance is virtually identical to body mount antennas e Center roof placement of magnet mount pro vides your most pea omni directional signal Can also mount on trunk lid e Unique Antenna Incorporated design provides Capacitive coupling Aluminum plate puts the ground potential right at the mounting surface for convenience Magnet and trunk lip the two easiest installations Place the antenna where you want it plug the cable into the trans ceiver No holes to drill Readily removed for anti theft protection Magnet mount supplied with 12 RG 58 U coaxial cable with PL 259 type connector trunk Sip mount with 17 of cable for magnet mount adherence Heavy duty 212 magnet in plastic cup with soft s n Holds at top highway speeds of 55 mph Trunk lip mount recommended for vinyl roof cars Since it won t walk it won t detune 0il can effect of cup resting on gasket provides a larger magnet plane than if the magnet itself were touching the surface yet there s less weight on the car less scratch potential All magnet mount benefits are standard not
63. prepares you so thoroughly for the next great leap forward in TV and audio digital systems Already top of the line TV feature digital tuning computer pro gramming is appearing and new digital audio recording equipment is about to go on the market NRI is the only home study school to give you the actual hands on train ing you need to handle servicing prob lems on tomorrow s electronic equip ment Because only NRI includes this designed for learning 25 diagonal color TV with electronic tuning built in digital clock and computer program mer as part of your training With this advanced feature you can pre program an entire evening s entertainment even key lock it in to control children s viewing As you assemble it you learn how digital tuning systems work how to adjust and service them You work with the same advanced features used in the new programmable TV s and video tape record ers It s exclusive NRI training that keeps you up with the leading edge of technology Exclusive Designed for _ learning Concept J The color TV you bu ld as part of NRI s Master Course looks operates and performs like the very finest com mercial sets But behind that pretty picture is a unique desi gned for learning chassis ELEMENTARY ELECTRONICS May June 1979 _ ea the only such unit in the world Rather than retrofit lessons to a hobby kit or an already built
64. quality Most were made in the U S A The PC boards were dou ble sided had solder masks and plated through holes More than enough Tex as Instruments sockets were included for the I C s One puzzle was that all the components were grouped and placed in numbered zip lock plastic bags but no code to the numbering was included For instructions I was expecting a schematic and a bag of components but I was very pleasantly surprised ki The people at Processor Technology certainly don t skimp on the packaging The SOL 20 arrives in a massive case that belies the size of the computer kit that is inside of it ELEMENTARY ELECTRONICS May June 1979 The manual is huge and very well or ganized It is not quite in the Heathkit category but still darned good There is a section very clearly giving the theory of this computer and an excel lent set of schematic and construction diagrams All the software included in the SOLOS personality module which acts as a firmware monitor is clearly documented Unfortunately the Basic 5 included is not The assembly instructions were well thought out and follow a logical plan with tests carried out as each phase of construction progressed One failing of the instructions is that it is stated than an oscilloscope is optional and that the function testing can be done with a VOM I found that not only is a scope mandatory but that I needed the 50 MHz Hewlett Pack
65. scope with 11 7 nSec risetime and a IPF 2 r i d EER u mas CIRCLE 47 ON READER SERVICE COUPON built in delay line for leading edge view ing of fast risetime pulses Full time 4X expansion allows any portion of a pulse train up to 40 full divisions long to be viewed without the use of a multiplier It is well suited for logic and pulse cir cuit applications The Model 517 is a dual trace 15 MHz scope with 5 mV cm sensitivity and reliable triggering up to ELEMENTARY ELECTRONICS May June 1979 30 MHz Priced at 695 including probes the Model 517 features auto matic se ection of chopped or alternate operation in dual trace mode depending on sweep speed selected The Model 517 is ideal for TV VCR audio and video maintenance and repair as well as de sign and troubleshooting of most digital logic circuits The Model 515 offers most of the features of the Model 517 in a lower priced 495 including probe sin gle trace version well suited to servicing and hobby applications TV sync separa tors are built in for easy locking to com plex TV video wave forms at any sweep speed and like the Model 517 it pro vides x y operation for vectorscope mea surements For all the facts write to the Hickok Electrical Instrument Co 10514 Dupont Ave Cleveland OH 44108 Mighty Mite Radio Shack s Realistic STA 7 AM FM stereo mini receiver delivers 10 watts per channel RMS into 8 ohms over 20 20 000 Hz
66. the circuit has returned to the state it was in at the beginning of this discus sion If mode switch S2 had been opened to its latch position no current would have been able to flow through R5 and R6 to charge C3 Since the charging of C3 is an essential part of the unlatching process it is clear that the module would have remained latch ed indefinitely In fact in the latch mode the only way to reset the circuit to its inactive state is by opening pow er switch S1 for at least five seconds REMOVE THE ORIGINAL 32 uF CAPACITOR AND REPLACE IT WITH A SIMILAR UNIT HAVING HIGHER VOLTAGE RATING RANSIS This pictorial diagram shows all the modifications that are needed on the S 210U module The 32 uF capacitor should be replaced by one with a 16 VDC or higher voltage capacity ELEMENTARY ELECTRONICS May June 1979 ACTIVE DURATION INDICATOR SENSITIVITY EY RELAY KI SU 210 CRYSTAL MODULE MICROPHONE This shows internal arrangement of The Third Ear Note how the S 210U crystal microphone is mounted over the hole in the front pane of the case Using a large factory built case such The above schematic shows the circuit of the S 210U The mod as the one shown here makes assembly of a project like this ule can be obtained from the company listed in the parts list a snap The batteries mount in the other half of the cabinet This gives the various capacitors time module in the pulse mode before th
67. the cur rent flows in the opposite directions through the diodes The two figures below show the battery connections to produce currents for both circuits In both diagrams the current flow is counterclockwise ELEMENTARY ELECTRONICS May June 1979 As stated earlier there is absolutely no difference be tween NPN and PNP transistors Both are used equally in electronic Circuits one is not favored over the other Base current causes collector current to flow in both To avoid confusion the rest of this discussion will be conducted using NPNs only as examples And from now on we will use the circuit symbols only Consider the action of the circuit below It uses only one battery to provide the base and the collector cur rent The path of the base current only is shown in the diagram QUESTIONS 7 Name the components through which the base cur rent flows P vat eo Le helt hee W 8 Into which terminal of the transistor does the base CIBTORE HOUT ne a PVA teenie ccmpraed fers 9 Out of which transistor terminal does the base current ROWS Van be lt cada dete be a N eT 10 Through which terminals of the transistor does no base current flow 2 0 0 0 2 cee ees ANSWERS 7 the battery the resistor Rb and the transistor 8 base 9 emitter 10 collector Can you remember the outstanding physical charac teristic of the transistor When base current flows in the preceding circuit what other cur
68. through a transistor e specify the relationship between base and col lector current in a transistor e calculate the current gain for a transistor explain how a transistor can be ON or OFF e compare the transistor to a simple mechanical switch e do simple transistor current calculation THE BASIC TRANSISTOR The diagrams below show several common transistors Fal ELEMENTARY ELECTRONICS May June 1979 in use today For each transistor the lower diagram shows how the leads are designated and how to identify them i most cases Eo COLLECTOR S N CASE 5 THE COLLECTOR A Pa ose IS CMITTER EMITTE COLLECTOR QUESTIONS 1 How many leads are there on most transistors 2 Where there are only two leads what takes the place Of the thirdlead o oo ee ee ee P 3 What are the three leads or connections called ANSWERS 1 Three 2 The case can be used instead as the diagram on the right This is limited to power transistors 3 Emitter base and collector af In its simplest form a tran sistor can be considered as two diodes connected back to back as in this drawing However in the construc tion process one very im portant modification is made Instead of two sep arate P regions as shown above only one very thin region is used VERY THIN P REGION Which has the thicker P region the transistor shown above or two diodes connected back to
69. to an output port where it could be read by a terminal device Our simple example has shown that a computer program consists of two things Instructions to the CPU to per form certain operations and data or information that the CPU needs to carry out these instructtons The latter may come in various forms and we will discuss only a few of them here Architecture Looking into the CPU that microscopic silicon wonder we find that it contains a number of dis tinct internal components The ones we will discuss here are the registers the program counter and the controller The number size and arrangement of these internal components is known as the CPU s architecture For the pur ELEMENTARY ELECTRONICS May June 1979 REGISTER TA PUTER READOUT Tell a computer how to tell itself what to do PROGRAM E E REGISTERS te E poses of this article we will refer to the architecture of the popular 8080 8 bit microprocessor Since the length of a data word for the 8080 is 8 bits or one byte each internal register will be able to store one byte Two exceptions to this are a couple of specialized registers called the stack pointer and the program counter These registers must store memory address information and since addresses in the 8080 can be up to 16 bits in length these two registers must be able to store two bytes We will not discuss the stack poirter at this time but the program counter
70. transistors FETS and SCR s e Fast good bad test indications The B amp K PRECISION Model 530 is one of the most versatile semiconductor testers available and can actually perform more tests on more devices than any instrument in its price class Features include Exclu sive patented fr measurement circuit Non destruc tive breakdown voltage testing Automatic lead and polarity identification in or out of circuit Measure ment of beta and gm Aural and visual test indica tions Testing of new power FET s CSA listed 310 For value the Model 520B industrial semiconductor tester is tough to beat Dynapeak circuitry with high low drive allows the 520B to work in circuit where others wont A complete test takes about 9 seconds Identifies all leads of transistors and SCR s and polarity CSA listed version available Good device indicated visually and aurally 175 pt PRECISION Model 5208 Semiconductor Tester e Tests diodes FETs transistors SCR s and Darlingtons in circuit or out Works in circurt where others won t wy Model 501A Curve Tracer Display characteristic curves on most any scope e Complete with unique Dynaflex probe At only 97 the Model 510 offers Dynapeak test method reliability with pocket size portability LED test result indicators Tests all types of transistors FET s and SCR s Digital stability never needs cali bration Complete with case and lead
71. transmitting be cause they can t hear you Never answer another operator s CQ Where s the challenge in that You al ready know he wants to start a QSO Instead try calling a CQ right on the same frequency and see who gets the first response After all why shouldn t every dav be a contest day On CW Now that you ve finally gotten rid of that old manual key in favor of one of the new keyers you can really burn up the ether with your speed Al ways send just a bit faster than you can copy because chances are the other op can t copy that fast either and he ll have to ask you to QRS slow down Z gt y V OLA i SA LZE R c ZZ ad 3 How to SACO NS IN RADIO AUNEEUR m UEARNING VRR e a BEING A LID It s a lot better and less embarrassing than if he asks you to QRQ send faster After all you did spend a lot of money on that keyer Since you did spend all that money with the idea of becoming a better CW operator it s a good idea to stay away from all of those abbreviations and Q signals Nobody understands them and you get more practice if you spell every word out On Phone Stay away from those inter national phonetics when sending your call Tres pass Something catchy and current is much better If those foreign ops can t get it thats tough They should watch more television Remember there are many more CB ers th
72. two front F 1 9 lens one front surface mirror 4a surface mirrors and building plans for buiding plans for cabinet and the LS 50 ae the cabinet screen 32 x 40 50 diagonal COMPLETE PACKAGE 369 COMPLETE PACKAGE 339 EXTRON GUARANTEES EVERYTHING the professional quality accuracy of description and avallability of components described in this ad After building your LIFESCREEN PROJECTION SYSTEM if you are not satisfied tor any reason return all components to EXTRON for instant refund LARGER SCREENS FOR THE LIFESCREEN AND LIFESCREEN lil SYSTEMS CAN BE ORDERED FROM OUR CATALOG Please sand me the tems checked below EXTRON LIFESCAEEN PROJECTION SYSTEMS C ONE COMPLETE SET OF LIFESCREEN PLANS 9 00 e amp 8833 Sunset Boulevard Suite 202 Rh umasa ONE COMPLETE SET OF LIFESCREEN PLANS 9 00 West Hollywood CA 90069 Se Iza O ONE COMPLETE SET OF LIFESCREEW Hi PLANS 9 00 Name I COMPLETE LIFESCREENt PACKAGE 339 00 Address JG COMPLETE LIFESCREEN H PACKAGE aw Ak 369 00 O COMPLETE LIFESCREEN III PACKAGE A SK 319 00 A a State Zip r EXTRON COMPONENTS CATALOG Appicabie toward any purchase 1 00 Ti Ai pricas F 0 B tactory Cal residents add 6 sales tax CARD NUMBER EXP DATE TOTAL SIGNATURE CIRCLE 9 ON READER SERVICE COUPON he ULTIMATE in CHEAP VIDEO BOOK amp KIT ONLY 42 95 CATALOG Audio Computers Instruments Kits amp Ass
73. unit on at a predesignated time and shut it off one hour later e SBE Key Com 1000 259 95 SBE Inc General Description A Acham AM transceiver for mobile P A ma rine operation Delta tuning s kHz is provided Power supply is 12 to 13 8 VDC with negative or posi tive ground Overall dimensions are 2 l in H x 5 9 in nied x 8 8 in D SCAN a thin layer of rubber cement around the top just inside the tube base Hold the envelope in a straight upright posi tion and set it down in the fresh ce ment Now apply rubber silicone me ment to the outside of the glass and base area Wipe off all surplus with a paper towel and make a neat joint with your fingers Let the envelope and the base dry overnight Many of our Solar Swinger s parts may be found in the junk box In fact low priced transistors are used in the directly coupled audio circuit If you are starting out cold and purchasing all new parts you may pick up a 2 transis tor AM radio kit from Radio Shack 28 214 for 6 95 Most all the parts needed for the Solar Swinger can be robbed from this kit Solar Swinger a great conversation piece and a sunny savings over the high cost of batteries There are front panel controls for volume squelch RF gain variable CIRCLE 69 ON READER SERVICE COUPON fosa 40 BE ETI noise limiter and Delta tune Switch es for CB PA noise blanker panel lamp dimmer
74. voltage this time is exactly half the supply voltage This condition is very important in AC electronics and will be returned to in the AC section SUMMARY At this point it is useful to compare the properties ofa mechanical switch and a transistor No current flow No current flow Full supply voltage across terminals Full supply voltage across collector and emitter Closed or Full circuit current ON flows as collector current Full circuit or load current flows through the switch No voltage drop across the switch terminals No voltage drop between collector and emitter The terms ON and OFF are used in digital electronics to describe the two transistor conditions just encoun Continued on page 86 ELEMENTARY ELECTRONICS May June 1979 Lab Test Elementary Electronics For Yourself In case you re not all that familiar with us we re not a publication for electrical engineers and other wizards No wav ELEMENTARY ELECTRONICS is ex pressly for people who like to build their own projects and gadgets and maybe get a little knee deep in tape solder and wire clippings in the process In fact we have a sneaking suspicion that our readers like us because they think we re just as bug eyed and down right crazy over great new project ideas as they are And I guess they re right E E thinks of you who dig electronics as the last of a special breed It s
75. weak signal and both their instructions and descriptive literature concentrate on nulling This might reflect the fact that they make loops for the 160 80 meter amateur radio bands 150 550 kHz VLF 40 150 kHz Loran and 10 40 kHz OMEGA bands where nulling of a strong local groundwave signal might be required in order to receive a skywave signal A loop an tenna produces sharp nulls on ground waves but the nulls are broad or non existent on skywave signals This per mits local interference to be attenu ated or eliminated while DX stations can be heard from all directions But when it comes to BCB DXing it s the gain of the system that really pays off It is possible however that some DXers might experience inter ference by a local station while moni toring DX so we ll cover our results in both peaking and rejecting signals Hook up The Palomar Loop Anten na system is connected to the receiver with a short length of coaxial cable anything in the thin category such as RG 58 or RG 59 will suffice Use the shortest possible length If the receiv er you re using for BCB DXing has a coaxial antenna jack simply use a matching plug on the end of the cable It is more than likely however that the shortwave radio or hi fi AM FM receiver you re using has screw ter minals for the BCB or AM antenna connection so simply solder a set of solder lugs to the free end of the co axial cable If your radio receiver h
76. weekly Relays From the 50 studio center in the Bush House headquarters BBC shortwave programs reach listeners via seventy high powered transmitters lo cated on ten sites throughout the world North American listeners are best serv ELEMENTARY ELECTRONICS May June 1979 a ti ed by stations on Antigua in the Carib bean and at Sackville New Brunswick and Greenville North Carolina These relays are shared with other broad casters such as Deutsche Welle and Radio Canada International Other BBC relays are located on As cension Island Cyprus and Singapore Programs reach these transmitters by means of undersea cable SSB radio link and satellite Many freduencies are used by the BBC to reach its estimated audience of seventy million and it would be im possible to list all those dial settings here North American listeners might check 11 775 kHz in the morning how ever and 6 175 kHz in the evening Al World Service times and frequen cies are listed in a monthly magazine known as London Calling It is avail able by mail for 10 00 per year Pic tures of station personalities and de scriptions of upcoming programs are included London Calling as well as mem bership in the World Radio Club can he obtained by writing to BBC World Service P O Box 76 Bush House London WC2B 4PH England E 49 no communications service that does not require precise measurement of the transmitter s carrie
77. will be of central importance You will notice I listed the program counter as a CPU component in its own right be cause of its importance but it is really a specialized register Let us imagine pur simplified 8080 as illustrated in figure 1 We see the dif ferent registers with connections be tween some of them so that data can be easily transfered among them Also il lustrated is the controller with the clock input Other CPU components include the arithmetic logic unit the address buffer and the instruction decoder What makes the whole thing go That is the function of the system clock which is usually connected externally to the CPU It is a crystal oscillator 77 COMPUTER READOUT which produces a rapid series of pulses which are used as a timing reference by the entire system It might be more useful to think of it as a metronome rather than a clock as some functions require a different number of clock pulses to be performed than others Every operation of the machine how ever uses this reference to time the sequence of its operations In an 8080 based system the clock frequency is typically 2MHz which may do some thing to explain the speed with which a computer computes Operation Let us now perform an actual addition of two numbers while examining what is taking place inside the CPU To do this it will be neces sary to have an addition program con tained in the computer s memory As mentioned ab
78. with a 0 5 total harmonic distortion The low profile receiver fea tures an equalization EQ circuit which produces high fidelity sound from the latest mini speaker systems like Radio Shack s Minimus 7s The EQ circuit uses both voltage and current negative feed back to tailor the low end response for CIRCLE 32 ON READER SERVICE COUPON 50 Hz bass in mini speaker systems The circuit can be switched out for use with full size speaker systems too It sells for 159 95 and 219 95 with the Minimus speakers shown in Radio Shack stores nationwide and in Canada Stereophone The Koss K 6A Stereophone offers the pleasures of private listening for those starting their interest in high fidelity It features low angle drivers which mini CIRCLE 49 ON READER SERVICE COUPON mize distortion 10 16 000 Hz frequency response range contoured earcushions professional styling and space age dur ability Suggested retail price of the K 6A is 24 95 For more information write to Koss Corporation 4129 N Port Washington Ave Milwaukee WI 53212 Continued on page 14 8 Newfrom NRI 25 color TV that tunes by computer programs an entire evening S Just part of NRI s training in x servicing TV stereo systems video tape and disc players car and portable radios entertainment 3 a re gt ELEMENTARY ELECTRONICS May June 1979 Only NRI home training
79. world and is universaliy accepted as the standard in ihe field of electronics training The Edu Kit uses the modern educational prirfciple of Learn by Doing Therefore you construct learn schematics study theory Practice trouble shooting all in a Closely integrated pro gram designed to provide an easily iearned thorough and interesting background in radio You begin by examining the various radio parts of the Edu Kit you then learn the function theory and wiring of these parts Then you buiid a simple radio With this first set you will enjoy listening to regular broadcast stations learn theory practice testing and trouble shooting Then you build a more advanced radio learn more advanced theory and techniques Gradually in a progressive manner and at your own rate You will find yourself constructing more advanced muiti tube radio Circuits and doing work like Professional Radio Technician A I y Included in the Edu Kit course are Receiver Transmitter Code Oscillator Signal Tracer Square Wave Generator and Signal Injector Circuits breadboard experiments but genuine radio circuits constructed by means of professional wiring and soldering on metal chassis plus the new method of radio construction known as Printed Circuitry These circuits operate on your regular AC or DC house current THE EDU KIT IS COMPLETE You will receive all parts and instructions meces
80. you can see It has a separate calculator type keyboard which duplicates the numbers on the QWERTY keyboard but is sim pler when entering numbers Again all function tests were passed The 16K RAM board comes as a semi kit This means that it is as sembled but jumpers have to be added or removed to create the options that you need The board is not burned in but two programs are included to do this Unfortunately neither is on cas sette or paper tape and must be entered manually More annoyingly both these programs require additional RAM to Operate and must be located at ad dress 0000 This doesn t allow the use of the RAM on the main PC board which is addressed in the high area of memory for the use of the monitor program and cannot be readdressed You will have to borrow a working memory board which is properly ad dressed from a friend or the store where you buy the kit Some people may nitpick that this particular mem ory board has dynamic rather than static chips but the day is long gone when the CPU had to halt to allow refreshing and the average hobbyist will not be held up by the refresh time The main PC board was the major task All ICs were socketted except two where there wasn t enough room There are repeated cautions in the manual about the handling of MOS devices but I found that using the bot tom of the chassis as a work surface 54 aN ge I a r s pIrY a MT Kate S The SOL 20 is well
81. you use in ee by Martin Weinstein WB8LBV vat Aas run ey PARTS LIST FOR WASHER WATCHER Ct C3 0 001 uF ceramic disc capacitor C2 C4 0 05 uF ceramic capacitor 1C1 IC2 LM1830 National Semiconductor LED1 LED2 light emitting diode R1 R3 680 ohm 2 watt resistor R2 R4 270 ohm 2 watt resistor PROBE ASSEMBLY FLUID GOING LOW PROBE FLUID LOW F You ll never get caught high and dry again your washer reservoir and the resulting mixture can affect the calibration Be fore you cement the probes and stopper in place check the operation of the unit by referencing the warning lights with visual observations Try to keep the solvent water mixture the same each time you refill in order to keep the unit calibrated When you re satisfied with the unit s calibration cement the probes into the stopper both on the top and bottom and then cement the stopper into the hole in the reservoir Silicon bathtub sealer should do the job very nicely The next time you take a trip let the Washer Watcher take some of the grief out of driving for you ELEMENTARY ELECTRONICS May June 1979 Some timely topics for the old time radio fan Wiesen THE PAST FEW WEEKS I have received letters from two collectors who have found cathedral radio cabi nets in near mint condition but the radio chassis were missing Now this seems strange to me because all the cathedral radios lve
82. 0 parts of our cassette and checked everyone elses cassettes Finally after over 6 years we positively linked cas sette failure or the prevention of failure to the slip sheets or liners the cassette We were not alone Scotch TDK and several others must have been doing the same research because they have also been coming out with special im proved slip sheets I MOLYSULFIDE A new chemical named molysulfide that reduces friction within the cassette several times better than graphite gave u success We developed polyester slip sheets with raised spring loaded ridges coated with a unique formulation of molysulfide and graphite The tape ran more smoothly than ever before within the cassette The new fer mulation is also much tougher than the graphite formulation so it is extremely resistant to wear Static electricity within the cassette was drastically reduced by the low fric tion and easily bled off so its tendency to erase very high frequencies was drastically reduced A very important consideration for often played tapes The molysulfide formulation gives both superior electrical and mechanical performance thus it has formed the ELEMENTARY ELECTRONICS May June 1979 bi oe poe JEE W basis for the birth of the new DAK ML cassette MAXELL IS BETTER Yes honestly if you own a 1000 cas sette deck like a Nakamici superior to DAK and you just might be able to hear the difference
83. 0 ITEMS GOVERNMENT SURPLUS MOST COMPREHENSIVE DIRECTORY AVAILABLE tells how where to buy YOUR AREA 2 00 MONEYBACK GUARANTEE Government Information Services Department E5 Box 99249 San Francisco CA 94109 433 Oee JEEPS 49 30 475 000 Items Buy In Your Area Buy Government Lands Guide Government Oil Gas Lottery Guide 2 00 Government Benefits Report 2 00 G SURPLUS Box 2009 EEP Syracuse New York 13220 HOBBIES amp COLLECTIONS NEW for catalog and monthly kit news P O Box 235 Jersey City NJ 07303 Electronics Kits for the Hobbyist 1 00 Hobbi Shack HYPNOTISM FREE Fascinating Hypnosis Information Startling DLMH Box 487 Anaheim California 92805 3 2 or Combo Each combination is designed to give your ad the largest audience available For further information write to R S Wayner Classified Ad Manager Davis Publicatons Inc 380 Lexington Ave N Y N Y 10017 j ELEMENTARY ELECTRONICS May June 1979 k mS ae Tt ttt aaa aaa Fae Classified a o y a oe V a al g alee ES N sheet z Y INVENTIONS WANTED INVENTIONS patents wanted cash royalty Auto electro mechanical mechanical devices Housewares etc We develop finance manufacture and market from an idea to perfected product Free evaluation and brochure Request Kit DP Pixonic Corporation 2
84. 00 postage for each year For change of address please advise 6 to 8 weeks before moving Send us your current mailing label with new address Advertising offices New York 380 Lexington Ave New York N Y 10017 212 557 9100 Chi cago 520 N Michigan Ave 312 527 0330 Los Angeles J E Publishers Rep Co 8732 Sunset Blvd 213 659 3810 Applications to mail at con trolled circulation rates are pending at N Y N Y and Sparta Illinois Copy right 1979 by Davis Publications tnc elementary elecironics vw 68 w 35 51 72 70 77 48 63 28 30 32 pk 79 98 Homer Davidson Bruce Evans Thomas Fox James A Fred Charles Green Larry Friedman May June 1979 Volume 19 No 3 RADIO ROUND UP Wireless Microphones be the first broadcast station on your block Signal Snare l ure those stations into your shack like Grandpa did How Not to Be a Lid nip those bad operating habits in the bud Solar Swinger chases the radio Clouds away Antique Radio Corner on insuring those priceless antiques SPECIAL FEATURE THE HISTORY OF ELECTRICITY The New Edisons after one hundred years of light what s next NEAT AND NIFTY CONSTRUCTION PROJECTS The Third Ear transistorized servant follows your every command Space Cushion Timer hel ps you avoid that next bumper bender Washer Watcher never another dirty windshield COMPUTER TIPS Simply Basic keep track of all those record albums Computer
85. 1 il 610 How to Repair Musical Instrument Amplifiers 288 p 50 l 718 Electromc Music Production 156 p 79 1 666 Experimenting with Electronic Music t80 p 103 il 546 Electromc Musical Instruments 192 p 121 832 Electronic Musical Insi Manual 210 p 7 lt 10 385 ll 503 Servicing Electronic Organs 196 p 812 x 11 145 l AUDIO RECORDING HI FI amp STEREO 1064 How to Design Build Test Complete Speaker Systems 336 p 6 95 1056 Install Everything Electr in Cars Boa s Planes Trucks 364 p 7 95 1042 Jap Radio Record Tape Player Screm Manual V 2 200 g 7 95 1017 Understanding Souna Video amp Film Recording 140 p 74 11 595 966 Complete Handbook cf PA Sound Systems 272p t4 li 7 95 736 Amateur Filmmaker s Hdbk Sound Sync Scoring 210 p 5 95 875 Micropne71es How Work amp How to Use Them 224 p 97 i 5 95 646 Acoustic Techniques for Home amp Studio 224 p 168 n 78 1 Handbook of Multichannel Recording 322 p 196 l 934 Photo Guide io AM FM Stereo Repar 288 p 261 632 Pictorial Guide to Tape Recorder Repairs 256 p 320 il 756 4 Channel Stereo From Source to Sound 252 p 102 il 634 Basic Audio Sysiems 240 p 302 l 4 95 689 Cassette Tape Recorders How Work Care Repair 204p 171 5 95 497 Tape Recording for Fun amp Proft 224 p 171 l 494 Audio Systems Handbook 192 p 129 681 Questions amp Answers About Tape R gt cording 264 p 102 il 716 Servicing Cassette amp
86. 10 Box 716 AMHERST N H 03031 CIRCLE 12 ON READER SERVICE COUPON ELEMENTARY ELECTRONICS DIGLKEY KE DD ACTS YY CORPORATION FREE Quality Electronie Components MN AK Hl RESIDENTS 218 681 6674 DON T FORGET OUR EES s RESISTORS TRANSISTORS CAPACITORS e DIODES s IC SOCKETS 4 PINS lt e SWITCHES AND MORE WRITE FOR FREE CATALOG I BREADBOADING amp TESTING DEVICES s DRAFTING SUPPLIES 7 E THE MA1073 by The a N i BBL ER Panasoni ACTEON capacitors w CLOCK MODULES OPTOMECTROMCS o DISCOUNTS WHEN COMPARING PRICES DATA BOOKS HEAT SINKS s WIRE TOOLS NATIONAL A MICROCOMPUTER it pe INTEGRATED Ae 1 C Socket Prices Gam rs k Slashed EMIOONDUCTE ATA MICROPRICE _ m m THE PROGRAMMABLE __ C SOCKETS CLOCK MODULE toe vot piv mim 16 ULIBARRI OYN WOLDERT AD ANC GIM WMAP 481 Tim 1 eo Pus WLDENT AD 3OCRfTY AEF LOW HLI z o i Ki AS HAP MOCENT 25s fla um a89 CROs LEVELS M p N 4 11 F r 5 iN we 3 7 a P gt 1547 T 1a x 5 a 1 1 A mine S e 7 agian 15 7205 imo 120M wy asa ous a f AN 25 wawa 1 47 3 awpa 30 1626 iw mapa 00 i0 na Lai H fr A Ww rm m p 153 3d pat tt oo x oo j masa 1 P s A amer V FEATURES Party 2 95 Aaye 41 J Anernddied aad Tesiz vvi only o 3 HE he paua a gt asndtad I phe iu i E
87. 10 cassettes and bribes to DAK Calif residents add 6 sales tax DAK unconditionally guarantees all DAK cassettes for one year against any defects in material or workmanship Why not order an extra group of 10 DAK ML90 cassettes for yourself or a friend We will add one free ML90 cas sette fc reach additional 10 you buy and of course you get all 3 bribes with each group of 10 tapes DAK DEPT EE INDUSTRIES INCORPORATED Call TOLL FREE 800 423 2636 In California Calf 213 984 1559 10845 Vanowen St North Hollywood CA 91605 33 ms SN a 34 should be time savings B amp K PRECISION semi conductor testers are designed for maximum speed and reliability to save you more time than any other testers B amp K PRECISION semiconductor testers are proved as highly cost effective answers to Test semiconductors without testing your patience The real value of using a semiconductor tester the needs of testing discrete semiconductor devices Recently they were evaluated by America s best known manufacturer of expen sive test instruments and the 310 Model 530 compared favorably with a 30 000 custom test system B amp K PRECISION has a model for most every application Model 530 Semiconductor Tester Measures unity gain fr to 1500MHz instantly e Nondestructive breakdown voltage testing Model 510 Transistor Tester e Completely portable for field testing of
88. 15 Desig Maintain CATV Smail TV Studio 288 p 100 l 8 95 57 95 997 The Handbook of Telephones amp Accessories 432 p 21511 9 95 ltoog CCTV Installanon Maintenance amp Repar 294 p 2 5C 8 95 5 95 2 25 6 95 5 95 3 95 8 95 5 95 S1 50 6 95 969 CBer s Handy Manual ct Base Stations 98 p 55 l 801 Master Handbook of Ham Radio Circaits 392 p 301 963 Home Brew HF VHF Antenna Handbcok 210 p 143 il 959 CBer s Handy Manual of SSB 80 p 42 l 685 The Complete Shortwave Listeners Hdbk 192 p 146 il 683 Piclona Guide to CB Radio Install Repatr 256 p 304 il 673 How to Be A Ham Incis Latest FCC Rules 192p 257 950 lI1 Dict of Broadcast CATV Telecamms 420 p 104 il 799 CB Radio Operator s Guide 2nd Edition 256 p 139 1 899 CBer s Handy Manual 48 p 735 The Complete FM 2 Way Radio Handbook 294 p 111 l 859 The Complete Handbook of Siow Scen TV 304 p 169 l 954 Practical CB Radio Troubleshooting amp Repair 406 p 169 597 RTTY Handbook 320 p 230 tt 933 CBer s Handy Atlas Dictionary 64 p 195 722 Amateur FM Conversion amp Const Projects 256 p 187 il 5 95 678 Modern Communications Switching Systems 276 p 171 I 17 95 581 Cilizens Band Radio Service Manual 288 p 84 ii 5 95 621 The 2 Meter FM Repeater Circuts Handbook 312 p 194 11 s6 95 ELECTRONIC MUSIC 743 Electronic Music Circuit Guidebook 224 p 180 l 843 Sourcebook of Electronic Organ Circuits 168 10
89. 2 year old Realistic brand The specs tell you why Speed accuracy of 0 0005 just 1 5 seconds after start up wow and flutter of 0 025 rumble of S only 70 dB DIN B This kind cf performance is superior to some broadcast and disco equipment and is made possible by a massive 12 5 8 3 1 lb platter resting directly atop a 12 pole brushless DC servomotor a controlled by a quartz oscillator and PLL circuitry But sm there s still more to recommend the LAB 500 Like all Realistic turntables the price includes dust cover and e cartridge And the cartridge i is our best made by Shure factory mounted in an integrated headshell for minimum mass and precision tracking even at 3 4 gram Audio response is a linear 20 20 000 Hz Tre automatic arm return is tripped optoelectronically assuring no change in record speed even at the end of the disc Out front controls inc uding electronically actuated cueing make operation easy a There are single play repeat and A anti skal cOn ee a All this including the 49 95 value cartridge and hinged cover and low profile walnut vinyl hase for 259 95 Rad ie Shaek By Realistic Sold only at Radio Shack A DIVISION 2e TANDY CORPORATION e FORT E sea 76102 VER 7000 LOCATIONS IN MINE COUNTRIE Retail price may vay at ndividuai stores and dealers ELEMENTARY ELECTRONICS May June 1979 GILFER S BEST SELLER SHORTWAVE Just Released 1979 Edition CONFIDENTIAL F
90. 40H 7800KC Series TO 3 LM340K 78LOOAWC Series TO 92 7900UC Series TO 220 LM320T 79MOOHC Series TO 5 LM320H 7900KC Series TO 3 LM320K 78MGT2C 78GUI TO 220 78S40PC 1150 1 60 29 Plastic 1 Amp 5 6 8 12 15 18 24 Volts Positive Voltage Regulator 1 2 Amp 5 6 8 12 15 18 24 Volts Positive Voltage Requiator 1 Amp 5 6 8 12 15 18 24 Volls Positive Voltage Regulator 100 MA 2 6 6 2 8 2 12 15 Voits Negative Voltage Regulator tAmp 5 6 8 12 15 18 24 Volts Negative Voltage Regulator 1 2 Amp 5 6 8 12 15 20 24 Volts Negative Voltage Regulator 1 Amp 5 6 8 12 15 18 24 Volls Dual tn Line Adjustabie 4 Terminal Positive Voltage Regulator 1 Amp Adjustable Positive Voltage Regulator Switching Regulator All new major manufacturer prod uction material offered Largest variety of device types tion of I C technology and multi metal expertise Over one million pieces in stock Contacts Price Contacts Price CHIPS MICROPROCESSOR available anywhere BIPIN 08 eZ BIN r 22 CPU s Stock level Part No Price 14PIN 12 24PIN 24 P 2114 7 50 I Stock level Part No Price 11400 3 PIN 48 40PIN a0 4600 8080A 5955 50 ak 1K x 4 300NS 20PIN 20 16000 6300 957 95 74000 2102LFPC 1 19 INTERFACE 1K 350NS Low Power GENERAL INSTRUMENT SUPPORT CIRCUITS 19700 2114 6 95 1 Amp Rectifiers Epoxy 1 5
91. 50 West 57th Street New York New York 10019 LOANS BY MAIL BORROW 1 000 50 000 secretly overnight Credit unimportant Repay anytime In credibly low interest No interviews collateral co signers Unique Financier s Plan Full informa tion 2 refundable Spectrum 79 Wall St 15 New York 10005 i BORROW 25 000 Overnight Any purpose Keep indefinitely Write Success Research Box 29263 5R Indianapolis IN 46229 MAGNETS MAGNETS All types Specials 20 disc or 10 bar or 2 stick or 8 assorted magnets 1 00 Magnets Box 192 E Randallstown MD 21133 MAIL ORDER OPPORTUNITIES GREATEST proven moneymaker Sell First Settlers of North America Recipes and keep all proceeds Special Offer Send 2 00 and SASE Omega_ Mail Order Box 243 Station A Fredericton New Bruns wick Canada ESB 4Y9 MEMORY IMPROVEMENT INSTANT MEMORY NEW WAY TO REMEM BER No memorization Release your PHOTO GRAPHIC memory Stop forgetting FREE infor mation Institute of Advanced Thinking 859DP Via Lapaz Pacific Palisades CA 90272 MISCELLANEOUS ENTER CANADA S FABULOUS LOTTERY De taiis Joe Davis 15 5763 Oak Vancouver Canada V6M 2V7 HOME BREW is now legal 2 50 Lewis Recipes Box 6156 Eureka Complete instructions CA 95504 AMAZING Secret Compartments Low Cost Defy Detection Hfde Your Valuables Many Types Catalog 1 00 Refundable Marietta
92. 670243 Price z ie 6 00 Logic P S Kit 5V 1A Reg ted 7070267 6 00 5 to 24 VDC Reg ted amp adjustable 5 A Sh Wt 15 Lbs 6MI60301 14 88 1O00000DODEREROANDAOOOODNLNDADAUNUANADAUGUAUGORI AODADOODADOOAADOARODOORADOOROODOOOODOODOODODOONO COMPUTER STUFF TTY MD33 ASR 348 88 TTY MD33 KSR 288 88 TTY M033 RO 248 88 TTY MD35 ASR 448 88 TTY MD35 KSR 388 88 DEC PDP8M 1488 88 IBM 725 1 O W Keyboard 498 88 Singer MD70 Work Station 1 O Yours for only 298 88 Singer Pertec 7 Track Key To Tape 4311 Com 228 88 Singer Line Printer MD52 350 00 Nova IBM Desk Top Term 748 88 Nova IBM Desk Top Terminat ASC11 system listed for 81 00 POSTAGE Please add postage All material is SPECIAL OFFER l 3 Line amp 11 Line catl directors with rotary dial Reconditioned Please state choice Sh Wt 10 Lbs 3 Line 8C0277 28 88 Sh Wt 15 Lbs 11 Line 8C0550 49 88 ALSO TOUCH TONE PAY ig AIW2 WAY LOUDSPEAKER KIT this neat accustic suspension system with 8 woofer 3 1 2 super horn Piezo tweeter Freq Resp 25 Hz To 25 Khz Walnut vinyl cabinets x 7h Hg x 11 Dp Max power 60 watts Imp 9 ohms Kit includes 2 en closures 2 8 woofers 2 Piezo tweeters grill cloth terminals accoustic damp ening inst as
93. 95 7 95 6 95 8 95 7 95 1 2 3 4 5 740 Sears 228 p 12 schemalics 618 Syivania Vol 2 212 p 8 schematics 760 Toshiba 160 p 12 schematics 502 Zenith Vol 1 196 p 12 schematics 562 Zerith Vol 2 196 p 12 schematics 668 Zenith Voi 2 180 p 36 p schematic foldout 838 Zenith Vol 4 196 p 36 p schematic foldout 918 Svcing Zent TV Modules 200p over 20011 CB amp HOME AUDIO SCHEMATIC SERVICING MANUALS Contain all the data needed to service each unit inciuding Complete schematic diagrams backed up with step by step troubleshooting info theory tips for isolating problems etc All 7 x 10 Each only 5 95 1026 Vol 3 Automatic Rado Admiral Midland Sharp 1025 Vol 2 Channel Master Coronado Hitachi 1024 Vol 1 Capehart Zenith 826 Vol 1 Kns Browning Hy gain Penney s 854 Vol 2 Teaberry Sitronix Pearce Simpson Unimetrics 858 Vol 3 Jotinson Linear SBE Royce Sonar 862 Vot 4 Pace Fanon Couner Dynascan Cobra 928 Vol 5 Radio Shack Realistic Surveyor Bett k 932 Vol 6 Xtal Tram Diamond Sharp 936 Vol 7 Latayette JIL Fanon 10 DAY FREE TRIAL NO RISK COUPON g tas BOOKS Blue Ridge Summit Pa 17214 Please send me the books indicated below O enclose Send postpaid l O Invoice me on 10 day tnai plus shipping i Book Book Book Book Company Address__ _ State PAo pa Pa add 6 Sales tax All orders outside LSA must add
94. AD 1304 is available in kit form for 199 95 mail order price Most of the circuit is on printed circuit boards There is a large mother board with sockets for plug in expander and control bandpass fil ter modules which are also printed cir cuit assemblies A sepafate meter as sembly is provided for tests and adjust ments The meter panel is internal and not normally seen when the cabinet Is secured There is extensive user alignment and adjustment Not difficult but time con suming and requiring considerable care just don t rush through the adjustments if you want optimum operation Performance The expander does just what it s supposed to do namely ex pand the dynamic range However limiting during mastering is performed on signal peaks not the average pro gram level yet expanders expand aver age program level This produces minor volume surges which do not exist in the tape to record master process As for the noise filter it also works as claimed If you have a very old tape recording with a relatively high hiss level or are listening to a very weak FM station the noise filter noticeably reduces the high frequency noise As with most expanders and noise reduction systems the Heathkit AD 1304 is somewhat limited in application if you are interested in high fidelity sound But if you want larger than life dynamic range and have signal sour ces that require hiss reduction the A
95. Amp Single Phase Stock level Past No Price AK 1K x 4 450NS Siock level Part No Price q sss ae i Price 4000 8212 1 98 MOS Dynamic RAM s 1 1Mullion IN4001 023 32000 WOSM 34 1400 ate wad Stock level Part No Price 1 amilvion IN4003 045 y 2800 9 16000 4K 4027 2 95 9Mtton IN 4005 055 fe aoe Et AK 4K x 1 300NS 16 ane Ida 84007 07 2 3 1700 8228 a75 21500 41 6 3 9 95 700 82 4 7 Part No 5800 8251 DS 4 95 93000 41 6 5 7 95 SWITCHING 1N914 100V 4NS 550 8253 14 95 300NS DIODES 2 as Nil stead 11000 8255 5 95 UVART s 400 8257 9 95 Stock level Part No Price WH Zilog 2 10 90 800 8259 14 95 44000 AY5 1013A 4 95 fa l 3300 6810 3 50 3800 AY3 1015 5 95 Z8O DMA Waf 32 20 2200 6820 3 95 1K CMOS RAM Z80 CPU sn gees 280 SIO 0 45 00 4200 6821 3 95 Stock level Part No Price Z80A CPU 16 20 Z80A SIO O 50 00 3000 6850 4 95 24400 5101 4 95 Z80 PIO 10 90 Z80 SIO 1 45 00 1200 6852 4 95 Latin Z80A PIO HE si Z80A SIO 1 SSe 50 00 ASOSAN ows Poari ELEMENTARY ELECTRONICS May June 1979 P O BOX 1035 EE 2 FRAMINGHAM MASSACHUSETTS 01701 Ov r the counter sales 12 Mercer Rd Natick Mass 01760 Behind Zayres on Rte 9 Telephone Orders amp Enquiries 617 879 0077 IN CANADA 3 LOCATIONS 5651 FERRIER ST 4800 DUFFERIN ST MONTREAL QUEBEC DOWNSVIEW ONTARIO H4P 2K5 M3H 5S9 Tel 514 735 6425 Tel 416 661 1115 MINIMUM ORDER 10 00 ADD 2 00 TO COVER POSTAGE amp HANDLIAG Foreign customers please remit
96. Are silicon and germanium ever combined in a tran sistor Hint What was said about diodes ANSWERS 4 OLLECTOR MITTER COLLECTOR EMITTER NPN PNP 5 Either or both could be silicon Either or both could also be germanium 6 Silicon and germanium are never mixed in any semi conductor HOW THE CURRENT FLOWS If a battery is connected as shown below to an NPN transistor then a current will flow as shown This current flowing through the base emitter diode is called base current and is given the symbol b 80 Would base current flow if the battery were reversed Base current would not flow as the diode would be back biased In the circuit below the base current can be calcu lated using ohm s law where E E n EIR and R a Find the base current in this circuit Hint Do not ignore the 0 7 V drop across the base emitter diode Your calculations should look something like this _ Vs 07V 3 07 2 2V _ ie R Tko iko ae mA In the circuit below as the 10 V battery is much higher than the 0 7 V diode drop we can consider the base emitter diode to be a perfect diode and thus assume the voltage drop is 0 V Calculate the base current OE 1 29 lb tka iko 10mMA Look atthe circuit below COLLECTOR DIODE Will current flow in this circuit Why or why not It will not flow as the base collector diode is reverse biased ELEMENTARY
97. BEEM O LIGHT LASER DIODES LASD 59 style N type 99 Designed in Hetero junction Coax for PULSE structure mode operation Rated amp 5 9 Wette Wavelength 904 nm approx Typ Forward V peak 1 2V Max For Cur 40 A SIZE 25 x 7 8 Cat No 92CU3508 2 for 6 asss s a oooagooconooaooonoo0pnn0ooaonnnnoopcnnnnoooacnooononcooonoonnnnnnnn CRIMP ON 100 RED BLOCK DISC CAPS aesorted vsluss SOX material 1598 50 SHOCKLEY DIODES most populer ewltching diods hobby A mnteeted x 10728 6 OPTO COUPLER 1500 leolation hobby materist U test 26294 4 CHERRY MICRO SWITCH 125 VAC L5A N C typs E 13 screw terminals 75528 1 29 SPST PUSHBUTTON MOMENTARIES rt angle pc mt on on e 3638 25 TYL s with 7400 s U teat dipa 2415A 30 RADIO AND TV KNOBS sast otylea sizas 9 217 60 TUBULAR CAPACITORS acot volts and alzes 218 55 LOW NOISE RESISTORS 4 W MIFI atc 226 SOPOWER RESISTORS 3 5 7 w axial pop sizes aaae 25 SURPRISE oll kinds of parte In a pak s 294 ree Mate 12 PANEL SWITCHES rotary slida toggis etc aas 295 A er eee tn qlr s t 60 COILS AND CHOKES rt paraoitic If ate z 297 60 TERMINAL STRIPS up to 4 soldar lage 334 60 PRECISION RESISTORS 4W 1 axial 363 fi 50 MICA CAPACITORS seat valusa 9373 0 ce cue cnc nucccves 0124835162 N 10 SET RCA PLUGS AND JACKS phono 402 Kc ont dau t
98. Bale u E lt P ae ee Q aoa WO a Fel a lt W UW a L E ae s Ob s Q lt l w w W Cm SK w sU Ow UW ww W 8 w eye W s s 8 Gene ape Feces a s s From the preceding prob lems you can see that Ve can be set to any desired value by choosing a transis tor with an appropriate value of 8 or by choosing the correct value of Ab Consider now this special example The object is to find Vc Go through the steps of the previous few ex amples You should have these values WON i 35 Ib 100 kQ 0 1 mA lo 100 X 0 1MA 10 mA 36 Vr 1 kR 10 mA x 10 V 37 Vc 10 V 10 V 0 V Here the base current is just sufficient to produce a col lector voltage of 0 V This is a yery important condition with many practical applications _ Look at the two drawings below and compare their voltages at the pointlabeled Vc Consider a transistor which has sufficient base cur rent and collector current to set its collector voltage to 0 V Obviously it can be compared to a closed mechani cal switch As the switch is said to be ON then the transistor is also said to be turned on or just ON QUESTIONS 38 From the above what can a turned on transistor be GOMPSIEd 107 ene a 4 ees es Se es 39 What is the collector voltage of an ON transistor ANSWERS 38 a closed mechanical switch 39 0 V J Now compare these two circuit drawings Since the Base circuit is broken that
99. D 304 might fill your needs For additional information on the Heathkit AD 1304 circle No 1 on the reader s service coupon L R INPUT LEVEL ADJUSTMENT CONNECTIONS TO RECEIVER OR TAPE RECORER AND FEST PETER AMPLIFIER Here you can see the nulls of the 5 9 Figure 1 This oscilliscope photograph shows the AD 1304 s dynamic range expansion which is explained in the text on preceeding page Figure 2 Pero et Bape Tag i amg meg F oor fat I x x eee Mi i and 13 kHz dynamic noise filters The top line shows when they are not activated pee agt 3 This scope shot shows how the high fre quency filter affects the top end of the spec trum The signal is 10dB down at 15 kHz SWITCHED AND UNSWITCHED AC OUTPUTS 120 140 VAC 50 60 Hz INPUT at Since the processer will utilize a receiver s tape connections the tape connections are moved to the processor along with the tape source monitor switch It can be built for 120 or 240 use ELEMENTARY ELECTRONICS May June 1979 ttt winar y n Y TsN a F o The Complete Idiot s Guide _ a to Becoming a Lich ei HE ASTOUNDING GROWTH in the e of amateur radio licenses issued in the past few years has resulted in a virtual logjam on the bands As a byproduct of this over crowding good operatin
100. D APPLICABLE TAX CIRCLE 29 ON READER SERVICE COUPON Extend your listening distance with FINCO S new Highest gain AUTO FM AMPLIFIER FINCO S self contained top of the line Auto FM Amplifier with variable gain control Increases Signal up to 16 Times Will Not Overload in Strong Signal Areas Provides Crisp Clear FM Reception m Switch for FM and AM Reception No Adverse Effect on AM Reception Extends FM Reception Range L E D Indicator Light Linear Patentiometer Gain Gontral SOLID State Dual MOSFET Circuitry _ Write for Catalog No 20 852 Dept EL 56 THE FINNEY COMPANY 34 West interstate Sen Bedford Ohio 44146 216 232 6161 INCO the Champion pr all Electronic independent Service CIRCLE 31 ON READER SERVICE COUPON Big opportunities Big prof its Earn quickly Full or part time Learn at home it s easy Do real jobs All Tools Materials Sup plied Accredited member NHSC Lic State of NJ Appd for Vet Send a and address for FREE boo ackimiihing Institute Dept 1472 i es s he Little Falls N J 07424 Don t Smoke WRITE NOW FOR McGEE S BIG SPEAKER CATALOG 1001 BARGAINS IN lt PEAKERS PARTS TUBES HIGH FIDELITY COMPONENTS RECORD CHANGERS Tape Recorders Kits Everything in Electronics 1901 McGee Street Kansas City Missouri 64108 o r FI REPORT AS HlFIREPORTS HiFi PORTS HI FIREPORT
101. E REGULATORS UNIT PART NO PRICE DESCRIPTION LM323K 5 50 78H05KC 5 75 3 Amp 5 Volt Regulator 5 Amp 5 Volt Positive Regulator TO3 7800UC Series 79 Positive Voltage Regulators Free Quarterly Updates 39 95 Finest Quality Socket available in the Nobody can match Texas Inst ruments quality a unique combina CO4000BE CD4 01BE CD4002BE CO40068E C040078E CD40088E CD4009BE CD4010BE CD4011BE CD4012BE CD4013BE CD4014BE CD4015BE CD4016BE CD4017BE CD4018BE CD4019BE CD4020BE CD4G21BE CD4022BE CD4023BE CD4024BE CD4025BE CD4026BE 1 CD4027BE CD4028BE CD4029BE CD4030BE CD4033BE 31 45 CD4C34BE 2 25 C04035BE CD4G640BE CD4041BE CD4042BE CD4043BE CD4044BE CD4046BE CD4049B8E CD4050BE CD4051BE CD4052BE CD4053BE CO4060BE CD4066BE CD4068BE CD4069BE CD4070BE D4071BE CD4072BE CD4073BE CD4075BE CD4076BE C04077BE CD4078BE CD4081BE CD4082BE CD4085BE CO04086BE CD4093BE 40 CD4104BE 2 25 CD4502BE 85 CD4508BE 2 25 CD4510BE 88 CD4511BE 99 CD4512BE 59 CD4514BE 195 CD4515BE 1 95 CD4516BE CD4518BE CD4519BE CD4520BE CD4522BE CD4526BE C04527BE 1 09 CD4528BE 69 CD4531BE 74 CD4532BE 1 19 CD4539BE 99 CD4543BE 1 39 CD4555BE 65 CD4556BE 65 CD4581BE 2 25 CD4582BE 79 CD4584BE 60 CD4585BE 40014PC 40085PC 40097PC 40098PC 40160PC 40161PC 40162PC 40163PC 40174PC 40175PC 40192PC 40193PC 40194PC 40196PC TO 220 LM340T 78MOOHC Series TO 5 LM3
102. HI POWER TRANSISTORS 220V npn TOS w 2797 3 24 PIN IC SOCKETS 2168 1 MMS312 DIGITAL CLOCK CHIP 100 s 1825 a s ont wel Wales ke 2 MM 5725 4 FUNCTION CALCULATOR CHIP 100 r 2036 kya q ais eaters 1c Ue ee 1 MM3202 ERASABLE PROM 100 e 3459 2 tere nd he SUS Raka p a ws SEZs 1 29 3 10 AMP 25V BRIDGE RECT comb style 2447 10 2N3S6S RF TRANSISTORS T0106 2N5133 2 3372 6 LINEAR SWITCHING TRANSISTORS ZN2905 anp TOS 3378 sae 0 2 AMP CYLINDRICAL RECT up to 1M u test i2 4006 6 OPEN FACE READOUTS LED red some nage missing mostly duais 3982 Sr eine PL 10 2N2222 or equiv TO 18 metal case v 1992 pawak SER ied 44 1 29 10 DATA ENTRY SWITCHES SPST 1amp norm open 128V z 321 i eee 8 TRANSISTOR RADIO EARPHONES 8 ohme Imped jo 204 1S FLUORESCENT OVERFLOW READOUT TUBES w lea je 23288 2 ALUMINUM HEAT SINKS for TO 220 339 1 2N5001 80V TRANSISTORS STUD 2800 3 MICROPROCESSOR SUPPORT CHIPS aust MMS 7B0 20 ser z 28pin T 6394 wae 20 6 CLOCK CALCULATOR CHIPS seat MMS378 75 5737 atc S638A1 alate y 2 DTL FAIRCHILD IC s gates and flip flops Dip 1003 3709 s 1 24 VOLT SO MIL TRANSFORMER 115V input open frame 1 x i a ve w 634 1 29 10 2N3704 TRANSISTORS silicon TO 92 case hfe 30C 100 5625 10 2N370 TRANSISTORS silicon TO 92 case hle 15 100 8626
103. ICS May June 1979 i Tune the slug in for more inductance Adjust C7 for increased RF sensitivity over the band and if oscillation occurs adjust for maximum capacity just short of the oscillation point Check the RF amplifier action in the reflex circuit by tuning in a weak sta tion and then connecting a 500 pF Capacitor approximate value be Continued on page 87 Need parts Hobby Mart page 89 L 2 2 4mH RFC 6800 Ts J 47OpF_L J2 Phone jack to fit your headphones L1 broadcast band loopstick antenna coil Radio Shack 270 1430 or equiv L2 24 millihenry RF choke Q1 HEP FO015 NPN FET Motorola or equiv alent Ri 470 000 chm Y watt resistor R2 1 megohm potentiometer audio taper R3 1000 ohm watt resistor R4 100 000 ohm watt resistor R5 6800 ohm Ya watt resistor Misc Plastic box approx 334 by 6 by 2 inches with perf board top section knobs Sheet aluminum bracket for R2 push in Clips for perf board hookup wire Also Hi Z headphones 2000 ohms or higher and a 6 volt battery or DC power supply 6VDC 47 The sun never sets on th One xy a Dxer s best chew addresses Bush House London headquarters of the BBC World Service World Radio Club DX Award cy a WA I ANG i Ws rs 7 a win th by oR ay BOVE rs ARYL AY K 3 ZZ U7 the shortwave dial setting on our family radio I picked up a trans mis
104. IME ICS LEDS READOUTS RECTIFIERS ZENERS TRS 80 ADD ONS 100 BOARDS PC AIDS TEST EQUIPMENT BOOKS SOFTWARE AND MORE ORDER BY MAM PHONE MASTERCHARGE VISA CODY Ok 1 ADD 1 50 FOR POSTAGE amp HANDLING 19355 BUSINESS CTR DR GES NORTHRIDGE CA91324 90 CIRCLE 36 ON READER SERVICE COUPON SUBSCRIBE TODAY TO DAAC ASIMOV S Science Fiction Magazine Now monthly To ISAAC ASIMOV S SF MAGAZINE Box 1855 GPO NYC NY 10001 C Enclosed is 5 95 for 6 issues outside U S A amp poss 6 97 C enclose 11 90 for 12 issues 1 yr prefer to use my MASTER CHARGE or VISA credit card however only these longer terms are available C 1 yr 12 iss 11 90 J 2 yrs 24 iss 22 90 Credit Card No Expiration date Name__ Address_ _ City_ aE State Please allow 6 to 8 weeks for delivery of first issue ELEMENTARY ELECTRONICS May June 1979 Signature_ _ H9 DO 71 ee W Customers THE THE WORLD OVER ARE CLAMORING FOR OUR GIANT var a YOU BET IT IS To be exact 0 8 of an inch COMMON CATHODE di GIANT replacement for iitronies 747 Left decimal 5V B mils per INCHER READOUT segment Red Cet No 92CU3327 only 2 99 2 for 3 THE FAT MALLORY AA MERCURY BATT Duracell by Mallory type RM 12 Same height as a AA but 5 8 DIA giving excellent AA substitute with extra power Factory Fresh Cat No ee s x
105. ION amp INSTRUCTION w USED Courses Books Lists 25 Marlborough Salem MA 01970 SMITH S 12 via resume Education CA 90211 COLLEGE degree by mail 256D South Robertson Beverly Hills t BECOME ENGINEER DJ Start your own radio station receive FCC license equipment records Free details Broadcasting Box 130 GE5 Para dise CA 95969 COMPUTER Programming BASIC or FORTRAN Electronics FCC License Mathematics Correspond ence study Free information Intermountain Tech nial Institute Room 13 Box 258 Jerome ID 3 y HOW TO RETIRE AFTER WORKING 15 YEARS New letter Sample 1 00 Stonehenge Box 386 Rexdale Ontario Canada M9W 5L3 DO YOU KNOW How to Write A Classified Ad That Pullis incluges a certificate worth 2 00 toward a classified ad in any of our publications For your ccpy send 1 50 includes postage to R S Wasner Davis Publications Inc Dept CL 380 Lexington Ye New York NY 10017 FUND RAISING SELF USE CATALOGS GIANT Gift Gadget product catalog Self Use etc Satisfaction Guaranteed 1 00 Order Dept EE579 Castleton New Fund Raising NorPro Mail York 12033 FOR THE HOME PRACTICAL tips for home garden and workshop can be found in 1001 How To Ideas Send 1 50 for your copy includes postage to 1001 How To Ideas 380 Lexington Ave New York NY 10017 GOVERNMENT SURPLUS i JEEPS 59 30 CARS 33 50 200 00
106. IRCUITS MONITOR SWOICH G e we TAPE Q OUT MONITOR TAPE MONITOR TO OUTPUT AMPLIFIER o SOURCE INPUT VOLUME CONTROL RECEIVER OR PRE AMPLIFIER ELEMENTARY ELECTRONICS May June 1979 Figure 4 is a picture directly off a spectrum analyzer oscilloscope The horizontal sweep is calibrated from 20 to 20 000 Hz Each major vertical di vision represents 5 dB each minor vertical division is dB An unpro cessed normal signal dynamic range of 20 dB is indicated by the two essen tially straight lines two major divisions from the top and bottom To this nor mal 20 JB range we apply the Heath kit dynamic expansion The maximum signal is expanded approximately 1 dB at midband But note the bass and high end are below the reference maximum level The average between the low high extremes and the midband is about 3 dB Added to the dB actual midband expansion the effective value is about 4 dB The low level signal is attenuated 3 dB below the norma levei at the midband by the expander In total the expander increases the dynamic range about 7 dB over most of the midband Noise Reduction The AD 1304 is designed to suppress continuous high frequency noise It does not suppress clicks and pops such as you might hear from a dusty or mishandled record or even radio static Noise suppression is accomplished by passing the signal through three triggered bandpass fi
107. Inter national costs 6 95 less battery Circle 75 on Reader Service Coupon the 2 to 3 foot long antenna wire to a 1 inch by 1 inch PC board The component locations are marked on the PC board albeit with somewhat blur red printing However if you start with the resistors you should have no dif ficulty orienting the various parts Helpful diagrams as well as a sche matic are provided but there are no step by step instructions It s assumed you know how to read resistor value codes Tip when installing the coil insert the leads bridged by a purple line into holes 1 and 2 The manufacturer suggests you first test the assembled circuit with an am meter but this should not be necessary if the assembly has been done with care especially being sure that the three transistors are oriented correctly This kit comes with a small electret micro phone and a battery cable but you must provide the 9 volt battery This wireless unit was tested at 108 MHz With the radio volume set at about halfway to maximum the test noise could be heard in all parts of the house including the hasement There was some reach into yard areas to a distance of about 35 feet from the mike The range was found to be roughly comparable to that of the fac tory assembled Micro Mini Mike sold by AMC The cost is lower but you have the problem of finding a suitable case to contain the PC board and the much larger 9 volt battery The mike o
108. L2 to the J2 headphone jack L2 serves as both a component of the low pass filter L2 C10 and as an RF load for the signal splitting action of C9 to D1 L2 is chosen to have a high value of re actance over the broadcast band and serves to broadly tune the D1 detector circuit over the range of 550 kHz to 1500 kHz The DC power for the circuit is sup plied by an external 6 volt battery or DETECTED A uad CIRCUIT T R4 C5 C6 A C2 RI DC power supply and C11 serves as an audio filter for the power input Construction The receiver as shown in the photos is built on a 6 inch long by 334 inch wide by 2 inch high plastic box with a perf board section installed on top Most of the components are mounted on the perfboard with push in solder terminals The input and output connectors JI and J2 are mounted on the front and rear of the box The 6 volt battery or power supply is con nected via two leads fed through a hole in the rear of the box The tuning capacitor C3 is mounted directly on the perfboard with machine screws and the volume control R2 is mounted on a small bracket made from sheet alu minum that is also installed on the perfboard Begin construction by cutting a perf board section to size to fit the top of the box Locate corner holes to fit the threaded molded screw retaining ex trusions located inside the top corners of the box Mount C3 on the perfboard in the location shown in the photo of OUT
109. No 035108 18 to 60 MHz MXX 1 Lite song RF Mixer 3 to 20 MHz Cat No 035105 20 to 17 MHz ea No a apas 5 80 ea SAX 1 Transistor RF Amp 3 to 20 MHz Cat No 035102 20 to 170 MHz Cat No 035103 5 80 ea BAX 1 Broadband Amp 20 Hz to 150 MHz Cat No 035107 6 06 ea WRI Ti E ng BACH p HOARE International Crystal Mig Co Inc I Mali bee Oklahoma City Oklahoma 231096 CIRCLE 13 ON READER SERVICE COUPON The American Heart Association WE RE FIGHTING FOR YOUR LIFE DX CENTRAL 11 840 kHz June in Minneapolis The mention of the bang up 1978 convention of the Association of North American Radio Clubs in Montreal last summer re minded me to remind you readers that the 79 gathering of listeners from across the continent is scheduled for the weekend of June 22 24 in Minneapolis Minn This convention will be hosted by the Minnesota DX Club in cooperation with the Department of Speech Com munication of the U of Minnesota Kim Andrew Elliott convention chairman has indicated among the spe cial events planned is a special ANARC television program Saturday June 23 at the Minneapolis campus of the U of Minnesota For details drop a note to ANARC Executive Secretary Dave Browne care of Association of North American Radio Clubs 557 North Madison Ave nue Pasadena CA 91101 Be sure to include a stamped self addressed en velope so Dave can send you the data on how to re
110. OY gu ev g ot ozy oloy 900 a oe g LOE 99E Ss ac 9S OC Ove BEBE SE DIE BOGE 82 0 L Z B90 Ls 92 SSO 2S O gS Oc voz gcoz 9282 olog gogg 2601 221 S 201 LI 0981 SS 9S BI 97d I icol 9 01 Segi Geol Bool Stel BIdI oggi JICA JAE 9628 989 20 g LZ 2920 9Sc8 BUCO JEZ o 9229 Bice 2z 9 S618 2619 29 19 L10 2910 SS I0 gS 10 gw 10 71 ELEMENTARY ELECTRONICS May June 1979 VER HAD THE ANNOYING experience of having the car in front of yours on the highway begin to kick up dirty water on your windshield and when you went for the washer button noth ing happened Well chin up bunkie the Washer Watcher is just for you It not only warns you when the tank is empty it warns you when you re near ing refill time before it s too late This handy device can also be an engine saver for those of you who have water in jected turbocharger setups on your Car The heart of the unit is National Semiconductor s LM1830 fluid detector which responds to the conductivity of fluids across its probe leads How It Works The LM1830 gener ates an AC oscillator signal in order to prevent electrolytic coating of the probes thereby reducing their efficien cy which is coupled to the probes by a 0 05 uF capacitor When the conduc tive fluid in the tank reaches a low enough level the resistance between the probes rises past the 13 000 ohm reference level set internally
111. One knowl edgeable collector felt that they were smuggled into Mexico Why would they do this Since there are only a few known radio collectors in Mexico they would no doubt be sent to other coun tries where radio collecting is becoming popular Number two why haven t more radio collectors installed burglar alarms Anyone handy with tools can buy equipment from radio catalogs to protect his home museum or work shop Very often insurance companies give lower rates to persons with ap proved alarm systems Number three why haven t radio col lectors made a list of every radio tube speaker etc in their collection and put it into a safe away from home loca tion Using file cards list the name manufacturer year built number of tubes condition amount paid approxi mate present value and any other fact that would help establish its value Most insurance companies will cooper ate by sending a representative to your location and will verify each item Fourth and last for this discussion why haven t radio collectors had the larger more valuable items in their col lections appraised There are a large number of antique appraisers but most know very little about old radio equip ment Radios are a special branch of the antiques field What the antique radio collectors need is a Blue Book of antique radio values similar to the one used by used car dealers A book of radio values would stabilize the radio col
112. PUT SIGNAL SPLITTER L 9 LOW PASS FILTER AMP LIFE D aE OTR BETECTOR 1 AMPA FIED E UDIO F oe gt FILTER p This block diagram shows how the signal is amplified as AF and RF then split and fed back to the tuned LC circuit The low pass filter separates the amplified audio signal ELEMENTARY ELECTRONICS May June 1979 the top of the receiver The capacitor used in our model had threaded holes in the bottom for easy mounting with machine screws and washers to lift up the stator insulating panels from con tact with the board surface If your capacitor does not have these mounting holes the capacitor can also be mount ed by a small bracket cut from sheet aluminum to fit front mounting holes Cut a bracket to fit R2 and mount it on the tront of the perfboard in the general location shown in the photos Use an internal toothed lock washer between the R2 mounting nut and the bracket surface to prevent accidental movement of the volume control Mount the remainder of the com ponents on the perfboard with push in solder terminals in the locations shown in the top of the board photo The lo cations are critical so follow the layout of Our receiver model Install a solder lug on the frame of the tuning capaci tor C3 for connection to the rotor Wire the board components as shown in the schematic and keep the connect ing leads as short and direct as possi ble LI is mounted with two push in
113. REQUENCY LIST Identifies those thousands of HF sta tions SSB CW FAX between 4 and 26 MHz 6 95 ppd Just Released 33rd Edition WORLD RADIO TV HANDBOOK The bible of the shortwave listener most comprehensive directory of Stations plus last minute info on skeds new band allocations best bands due to sunspots 14 95 ppd SPECIAL COMBO OFFER Both books only 20 ppd NEW FREE GILFER SHORTWAVE CATALOG e Receivers Antennas Preselectors e Tuners e Headphones eClocks e Cali brators e AM FM amp TV Directories e Logs and QSL Albums e Report Forms GILFER SHORTWAVE Dept EE5 Box 239 Park Ridge NJ 07656 CIRCLE 25 ON READER SERVICE COUPON Old amp Rare Coins 3 95 BUYS ALL THIS 1 1968 Cent Unc 1 1969 Cent Unc 1 Wooden Nickel i Oid Indian Head Cent L V Liberty Nickel oe 1 Buffalo Nickel i t Large Cent eng fv bd 1 Cent 1920 or Older y EN it 1 S Cent 1920 or Older Vv ajc l S Cent 25 yrs or Older V i 1 1943 WWII Steel Cent Resan A N 1 Cent D Mint 25 yrs or Older or 3 95 BUYS THESE TWO RARE UNCIRCULATED COINS The mint made a mistake but we didn t Now is your chance to take advantage of their mistake ePLUSe OF 695 BUYS EVERYTHING iy BOTH OF THE ABOWE SPECIALS 3 Q 1955 5 Cents Poorman s Doubie Die With Every Offer you Receive e A Few Starter Coins o A Free Catalog e 5 Asst Foreign Coins Add 50 e One Irish Pen
114. RS 80 SOUND ACTIVATED SWITCH vox LINE CORDS 18 2 cond w plug 27uF TANTALUM 30 ania 22 uF TANTALUM 1 V arel Jut TANTALUM 35V assed 17 TRANSFORMER 100ma PC mounl 1N4148 SWITCHING DIODES full lead TEXAS INST TTL DATABOOR 250nsec 21102 RAM 650nsec NLO RAM 1142 1147 6 POS ROCKER DF SWITCH 4 POS ROCKER DP SWIKCH 1G00uF 25V uprile cap TRS 80 l k MEMORY ADD ON KIT TRS 232 PRINTER INTERFACE 3 MADOUT MAN 74 equal NS23 8 14 PIN SOLDER TAH SOCKETS 16 PIN SOLDERTAIL SOCKETS 24 PIN SOLDERTAIL SOCKETS IN4001 50V 1A RECTIFIER SIV 1 WATT ZENER 12V 1 WATT ZENER 25 AMP 100 Piy BLOCK BRIDGE SOLDERING IRON pencil type JOW 47uF 6 39 uprite by tic 22ut 250V axtal bytic 40 COND RIBBON CABLE per sE 104 KIT 2 paralel 2 serial port PROM PROGRAMMER 2708 16 trom OAF SHUGART MINIFLOPPY DRIVE SA400 5 READOUT CC PND 503 TRS 80 SOFTWARE CASSETTES Detcripton SARGON CHESS L STAR TREK 8 SCIAN GAME SAMPLER B TAROT L in CRIMBAGE I REAL TIME LUNAR LANDER IL BRIDGE CHALLENGER it AIR RAID LE PLOT UH OIHHIO VIE SMALL BUSINESS BOOKKEEPING k E DARY BK RHYTHM PROGRAM UW MICRO TEXT EDITOR I INVENTORY MODULAR 1 1 EDIT BO text editor I1 12K 13 88 This Honeywell No ASC11 encoded microswitch data entry format keyboard Comes with fully pop ulated I C boards Some 100 1 C s 7100 amp 71400 series or some are dot matrix 1 C s LSI ch
115. Readout how a computer instructs itself THE WIDE WORLD OF SHORTWAVE LISTENING DX the BBC World Service this is the British Broadcast Empire Curing Receiver Images keep your receiving Circuits clean KEEPING UP WITH CB Kathi s CB Carousel Kathi programs the Pace 8117 CB XCVR Checkout four more of the most interesting rigs get the going over ROUGHING UP SOME NEW EQUIPMENT e e Checks Out the Redco RFC 50 Frequency Counter e e Checks Out the SOL 20 Persona Computer Kit e e Checks Out the Palomar Broadcast Band Loop Antenna e e Assembles the Heath Active Audio Processor OUR REGULAR DEPARTMENTS Hey Look Me Over the newest products that it was worth waiting for DX Central our resident DX pert goes over some pertinent points Newscan some very interesting developments Bookmark by Bookworm Hi Fi Reports our audio editor equips a disco Basic Course hurry up and get started on transistors Literature Library Ask Hank He Knows Hank fixes everything 63 INSTITUTE OF HIGH FIDELITY AUTHORS IN THIS ISSUE Jorma Hyypia Don Jensen Kathi te Martin Brian Rogers Hank Scott Gordon Sell Walter Sikonowiz C M Stanbury Thomas Sund strom Martin Weinstein Tom Williams and the ELEMENTARY ELECTRONICS editorial staff Cover photo by Dave Niedo ELEMENTARY ELECTRONICS May June 1979 328 WAYS TO INCREASE YOUR ELECTRONICS KNOW HOW SENO NO MONEY We ll invoice you
116. S SCNG JET AIRLINER 8 9 COMMAND ALBUM 0 ALBUM NAME BCOK OF DREAMS ARTIST STEVE MILLER t SHOOTING AHEAD IN ELECTRONICS If you want to go further in your exploration of transistors you can order the book from which this article was ex cerpted ELECTRONICS by Harry Kybett Write to Self Teaching Guides Department John Wiley amp Sons Inc Pub lishers 605 Third Avenue New York NY 10016 The price is 7 25 postpaid If you want more information about the popular Self Teaching Guide series just ask and they ll send you some Be sure to mention you saw it in ELEMEN TARY ELECTRONICS C COMMAND ALBUM ALBUM NAME BIG BAND ARTIST TOMMY DCRSEY ARTIST TCMMY DORSEY C CMMAND SONG SCNG 7 MARIE ARTIST TOMMY DCRSEY ALBUM BIS BAND COMMAND EXIT READY ELEMENTARY ELECTRONICS May June 1979 86 l OE A aaa ap Ld _teries are not Computer Readout Continued from page 78 memory for future reference by the computer The MOVM A instruction at position 9 in our program causes the contents of the A register to be moved to that location in memory who address is stored in the H and L registers The final instruction is the halt in struction HLT which stops program execution If it were not there the pro gram counter would merrily continue to step through all available memory sometimes with intriguing results This program could be located any where in available m
117. S HEF R PORTS HIF REPORTS HIF REPO REPORTS Hl Fi REPORTS HI FI REPC lt REPORTS HIFI REPORTS HI FI REPOR FI REPORTS HIFI REPORTS HI FI REPOR HI FI REPORTS REPORTS HI FI REPORTS HI FI REPORTS LFI REPORTS HIF REPORTS HI FI REPOR IREPORTS HIFI REPORTS HIFI REPORT IREPORTS HI FI REPORTS HIFI REPC EPORTS HIFI REPORTS Hi Fi REPC PORTS HIFI REPORTS HI FI P PORTS HIFI REPORTS ULF REPORTS s A pair of performers that can keep in step with the demands of disco By Gordon Sell WITH THE BOOMING POPULARITY ot disco dancing disco musi and disco parties many people are converting basements and spare rooms into discos complete with flashing lights and high power audio systems The nationwide popularity of disco was recently brought home to me in a letter from a reader in Eugene Oregon He and a friend had rented a large old house together and wanted to use the giant living room for disco parties They were trying to find a sys tem that was high powered yet rugged and easy to use in the often confused environment of a party In such a situation you need the power to drive four speakers at high Realistic STA 2100 CIRCLE 32 ON READER SERVICE COUPON levels at least an 80 plus watt per channel that s only 40 watts per chan nel with four speakers receiver or power amp in order to avoid clipping at disco sound levels Another considera tion is more mechanical Turn
118. S i nan 1 4 a LM m t L H a EH _ s AN IC smeo worhrind For saa maintenance y 2M x 138 Morn n t bips supande k 2 n ge i 130 Dare I isterali or 10 a dapis WC Spanks Mesir Bevetifatls rs i z a 7 s ag reaS oh NIAL Rows ip AOM ama PR of NAA o 5 i a Canis Tererlaced with CRT or Tries v y 2 OT E P 1RE WHAFPING WIRE lt w wr eel NKU ar ne tig pep S SE CUT FRE STRIPPED eds a resect eae ay LOM Four 0 2 y 2 P76 sne i h a e on martian a gt re i met x h 0 7 oh o 70 a 7 u Y Q 44 Man 1 4a p gA i ok 75 oh d T 1 4 Te 3 es re 4 108 H om 07y u oe an i 3 ad h gt on SA ms x m u ga 7S n m wa 44 PI ad se o ons TOET b 2 4 Vo 3 4 SEPEN Oe FEI po M O a a stat GE Or w qA m ol r a i ee N aa 0 5a oe 5 43 b u be W y 155 A a Bs 7a 525 N oO 1 n Toe H a an 134 4 125 aa H ni m aaa 4021 u gt p w i ES n PANASONIC POLTESTIR CAPACITORS p 2 a 4 n x 14 1s Fad F178 Ow Part No 500 K Quce and les To intial Im o an A 1 248 oM bded 1 1m 04 nm ki i IM x 4 DEGI KEY aM oli B CORPORATION BOOK SELLER 12 A oth q a MATION AL frai CONDUCTOR DATS BOOKE te s 5 L gt ADAM OLSON DMICEOPEOCESSOR SERAS 4 a oan PU HOWARD W SAAS n on DA 4060 1 HaTeIn 3 el 264 nn BDOOILAL WORLD TY nag pel z AMO INTROD
119. SERVICE COUPON a practical new book project by project in as plain a prose as one can find anywhere The book is Build It Book of Optoelec tronic Projects by C K Adams Step by step instructions and clear explanations tell how to build everything from a digital tach ometer to a two level logic probe to a garage nightlight The reader learns by building Optoelectronics packages loaded with good ies like LEDs LCDs displays photodetec tors optoisolators and photodiodes Every project comes with complete parts lists and pin data every IC is listed by type number and detailed in separate package diagrams calling out every pin function detailed cir cuit descriptions fast reading reviews of pertinent concepts circuit options and can be used in project after project Published by Tab Books Blue Ridge Sumit PA 17214 Getting the Data Out NCR Data Com munications Concepts an introduction to the principles characteristics and testing of ar Data transmission CIRCLE 60 ON READER SERVICE COUPON i i n for the Computer Hobbyist is Cag i gt Soft cover C a 220 pages f z 4 6 95 k i E Pete Conta data transmission circuits has been added to the Bugbook Reference Series Edited by Titus Titus Larsen and Rony the text con tains practical and useful information for electronic data processing technicians com munications engineering students and com puter hobbyists The bo
120. Stude 192 p 153 70 Elecironic Puzzles amp Games 128 p 75 ELECTRONIC TEST EQUIPMENT 132 How to Test Almost Everything Electronic 169 p 144 il 730 Ettective Troubleshooting with EVM Scope 238 p 185 l 10412 How To Design nid Elects instrumentation 420 p 219 792 Buiid tt Book of Mimature Test amp Msmt Instr 238 p 151 g 472 Working with the Oscilloscope 104 p 183 r Gy 672 Undersianding amp Using the VOM amp EVM t92 p 187 l 927 How l0 Use AF amp AF Signai Generators 238 p 162 il 70 Elecironic Meawremenis Simplitted 240 p 217 il 729 RF amp Daia Test Equipment You Can Builg 252 p 217 i 877 Unde amp Using Modern Signal Generators 294 p 120 il 664 Unoerstanging amp L sing the Oscilloscope 272 p 170 1 PF Hon To Uae ur TV Tes Instruments 256 p 230 t31 Test dost us for Electronics 1929 15514 r Hov root amp Repaw Elect Test Eqpt 252 p 143 ne ng Modern tlectr Svrinq Test Equipinent 252 94 W s O Use Your scilloscope 19 p How se Test Instr in Electronics Servicr ig 56 p 234 il Vecto copes Scones Sweep Marke Generators 25b p 483 4385 550 4 95 7 95 6 95 5 95 7 95 1195 4 95 5 95 6 95 8 95 8 95 5 95 9 95 7 95 5 95 4 95 5 95 5 95 5 95 595 9 95 7 95 6 95 4 95 4 05 9 95 6 95 4 95 2 50 4 95 4 95 3 95 5 95 5 95 2 50 3 95 5 95 6 95 5 95 4 95 3 95 5 95 3 95 5 95 5 95 95 3 95 6 95 5595 5 95 4 95
121. T 06064 North American SW Association P O Box 13 Liberty IN 47353 ELEMENTARY ELECTRONICS May June 1979 Meet Super Grip Il the great new test clip from A P Products New duck bill contacts are flat won t roll off IC leads Open nose construction enabies probe at IC leg Pin rows are offset for easy atiach ment of probes Contacts are gold piated phosphor bronze Contact comb construc tion separates contacts with precision No shorts Heavy duty Industrial grade springs for firm contact pressure and a good grip when pulling ICs They ll keep their spring indefinitely No New narrow nose design makes Intermiftents it easy to attach on high density e boards And now you can test ICs Steel pivot pin Engineering grade New button head pins keep probes with only 040 between thermoplastic body moided around from siding off Straight pin modeis opposing legs contact pins Made fo lasti tor logical connections The new AP Super Grip Il ts without bulit to stay useful indefinitely 22 24 28 36 and 40 pin models at your question the best way there is to trouble Try one You li find 8 14 16 46 LS 48 20 nearby AP store Make sure it s your AP shoot DIP ICs store You get positive contacts No Inter Need the address Call toll free 800 mittents No shorts Ever AP PRODUCTS 3241 966 amp And ask for our complete A P So It s endlessly useful to you and it s INCORPORATED cat
122. TICKER PRINTING DEVICE Cheap Simple JT Tampa FL 33622 i 30 00 HUNDRED stufing our circulars into stamped addressed envelopes No limit Beginners Kit 2 00 Colossi Box 318 DC Brooklyn NY 11204 MAKE More Money In Mailorder HACO Box 846 Nashua NH 03061 ASSEMBLE products at home Many opportunities paying high weekly profits presently available With out Investment Businesses 92 D2 Brighton 11th Brooklyn NY 11235 1200 00 MONTHLY CORRECTING PUPIL S LES SONS Start Immediately Free Report Send self addressed stamped envelope Home Box 9201 SBBL San Diego CA 92109 HUGE PROFITS selling gifts novelties Newberry 197545 FM464 Seguin TX 78155 300 00 WEEKLY Mailing Circulars Write McGuire Box 91054 Tacoma WA 98491 83 501 00 FREEBIES WAITING GOVERNMENT DIRECTORY 3 00 PALMER B1244DG Phenix City AL 36867 ern Sn re te SO eee eee CABLE FM BROADCAST STATION Investment experience unnecessary Home operation possible Excellent income reported Free details CAFM Box 130 GES Paradise CA 95969 BUSINESS AND FINANCING CONSULTANTS NEEDED Complete training Large commissions Pyramid Finance 500 West Central Sulte 200 Mt Prospect IL 60056 400 First Week with Ad Clocks or money back Your own Advertising Business Action Ad Clocks Room AC 107 IE 1512 Jarvis Chicago IL 60626 BUY WHOLESALE Hundreds of Items 2 00 Eriugs giant catalog refundab
123. TRAINING PRINTED CIRCUITRY SERVICING LESSONS You will learn trouble shooting and servicing in a Progressive manner You will Practice repairs on the sets that you construct You will learn symptoms and causes of trouble in home portable and car radios You will learn how to use the professional Signal Tracer the unique Signal Injector and the dynamic Radio amp iectronics Tester While you are learning in this practical way you will be able to do many a repair job for your friends and neighbors and charge fees which will far exceed the price of the Edu Kit Our Consultation Service will help you with any technical prob Jems you may have FROM OUR MAIL BAG Ben Valerio P O Box 21 Magna Utah The Edu Kits are wonderful Here I am sending you the questions and also the answers for them have been in Radio for the last seven Years but like to work with Radio Kits and like to build Radio Testing Equipment l en joyed every minute worked with the different kits the Signal Tracer works fine Also like to let you know that feel proud of becoming a member of your Radio Tv Clul Robert L Shuff 1534 Monroc Ave Huntington W Va Thought i would drop you a few lines to say that I re ceived my Edu Kit and was really amazed that such a barzain can be had at such a low price 1 have already started re iring radios and phonokraphs My riends were really surprised to sce me et into t
124. U S coins The Postal Service will not accept envelopes for mailing back to them with foreign stamps I know because I have received stamped self addressed envelopes from both Canada and Mexico and have been unable to by James A Fred use them Another problem I have is receiving letters with requests for help that do not contain return postage This is especially true with requests from foreign countries Airmail in most cases costs 31 per ounce International reply coupons can be purchased in First Class Post Offices also International Money Orders These two items can be used to send funds to any country that is a member of the International Postal Union African Antique Some time ago I received an interesting story and a photo of a round metal table model radio from Ken Greenberg of Skokie IL The radio shown in one of the photos was purchased in the early 1950 s It was made by the Berec Bat tery Export Company in London Eng land for use in Africa It was primarily used in Rhodesia and was sold to the natives for a small sum of money in an attempt to educate them via radio Mr Greenberg s radio covers the medium and shortwave bands and op erates on a power pack consisting of 1 5 and 90 volt batteries It is a very rugged moisture proofed radio that played surprisingly well when its at tached wire antenna was extended The radio uses a IR5 185 1T4 and a 3S4 tube It has a two speed verni
125. UCING tb BOOKS 3 L on 5 UF OC kale Cor oo 7 4675 n x vm w Boat al 4061 2 4082 n 30 U 1 67 Tal She 338 ito fiom a G PANASONIC METALL ITU CAPACITORS MA1010 AWD CLOCK MODULES FIF 7 SIE MOUNTS w PaL wP tQ Thien Waki WAAT Feta Awd LAIAT CLOG u bus UE G7aR aL i Low PowrR 150 Or Dame dg i Braces PANASONIC RESIN DIPPET Li GAPACITORS TO PER TE 4 i T apr AnA ILA MO hme OT Ne na ih Ue al b 193 MOUNT 16 aoar lt n Ka M001 om EHIH 67 woui ENG ADAPTED ER MA D tw OW OR WA vYOR1WAC DICO ING CMARGE HANDLING es VOLUME CHARGES wr cae D SCOWNT 00 9 99 Add 2 00 alel ull 4 0 00 998 99 k is hdd 0 75 100 00 5749 99 Low ne h 00 49 99 Add 50 50 250 90 4490 90 lea 15 Se alae AP Sigg 21028 0 00 599 99 Add 0 25 gt 2 00 00 9909 9F Lew 10 F n SET ans 9 g DOUBLE DIGIT DISCOUNTS SAVE YOU EVEN MOREL cman ms J STRANOGED ESNet esterCharge eri BOOK uP P WARE O tos st hiet mim be POY MED y MOTALLIZEC mai APACIIORS yey DIGI KE Y i Means r CORPORATION E a w Toll Free ii ualiy Electronic Components oo B e ria P PES MIRE CATALOG T Wats N QE iver Fold a seen u ee SE TT TAI TE yal Era __ aaa e WT War WD rn ina GEF SESI TR ae sss it Ka ae ee s a ELEMENTARY ELECTRONICS May June
126. VN YWSGNN SONOS ON LINIHd B80 SI N3HL i Z dI OLE c0rv 0105 2960 f lt WOSTV INTUd LS V J0113 PIOM ul1 SuId jou Aq 1019 OU SI 313U ullUuo53 no Inun ysip y 0 aim uom 4 suluvaw anbiuyss UO1 9891 JAIesaU 34 SAO dwa 3 Jey UI ensnun JEYMIWOS SI IT 0601 0001 s utl pow ezs ay YUM p l urtu 1 luI ST W3JSAS NOILOAUNOD YOUN IY ejep BULIIIUS IIYM syRISIW e jew noA pjnoys NOILOJAAOQ UOUAJ savy s op ng INVA JO Junoum jqe 19 pisuo5 z s rimb ir siqi Amua ue jo BPAOWII 10 PIA01d you s op y poys Ajqeuoseas uueidoid ay doay oL AVY JO sonnuenb age saye yorum SOTQUIIVA JO S 331e q9 Avie ue sn jou s op weigoid y asnes 3q SI SIU Joyndwod ay ur Alowsw jeuonippe Aue Juumb r ynoqyam ejep MoU y uo sppe durs pue ezep sno taadId INOA JO pu y s jesoj jjesnew OINE puewwos atvqan 3ul 0801 aul ye paysi dwosse st siu L ysip y oluo s ru gp uino jJHA Ki snonunuo5 071d Butuunaq e se pu Jomtado OPEL INS EWE UE Se ZIUA JEN put Sia JUSUIAdXS SHUO pHa 10 StuPrgo id uo WEY NSUOS g osje s AE swear Suipwoq pue JEqesey s AME 10 S3SHE1S ay Sur daay put sqyodal sa 1uatudinba Supa Saja x duias Hulssasord s sast asiaA SHE atul se ap YOnSs spf Fayndwios ayy OO89 a LAS up Burs wasdAs ralnduiuos umo SI YING Sey aH sa lnduuos yA PUEY pjo ue st tumagodd siyy dn jas oym LEW pai4 ALE pjo sig A usaqyy w
127. a prominent west coast antique radio appraiser who had seen the tubes and other collectibles the man had and had filed the proper paper work to prove these tubes existed The collector was insured and his monthly premium was quite a lot of money The insur ance investigator was unhappy as were the local police because sthe collector had promised to install a burglar alarm but hadn t done so After the insurance company investigator interviewed the appraiser by telephone the claim was approved to be paid Continued on page 92 ELEMENTARY ELECTRON ICS May June 1979 ill by Kathi Martin KGK 3916 r CB Carousel Kathi puts the Pace 8117 computerized CB through its paces or something like two years compu Fi CB transceivers have been the big talk at equipment shows The trou ble is that s just what its all been talk Why the last time I looked and listened it was one of the heavies in the com puter and calculator marketplace that was going to turn CB on its ear with a computerized CB With the notable exception of SBE s excellent Key Com 1000 you can read about it in this issues CB XCVR Checkout which was developed from their model 55 ma rine VHF transceiver the traditional CB manufacturers have ignored com puter control for CB sets With all the developments in VHF UHF scanners you d think some of the technology would rub off on some of the other CB biggies but up to now it Hasn t Now how
128. af _ter triggering It then returns to its in active state where it rests until re trig gering occurs Then the process repzats itself Construction Adding pulse mode capability to the S 210U is a simple matter All it takes is some auxiliary circuitry to sense the latching of the F MANY CREATURES On this earth SCR and to unlatch it again after a user selected time delay Unlatching an SCR can be accomplished by opening _ a eee asss by Walter Sikonowiz May June 1979 mentary This electronic servant will jump at the snap of your fingers i A a switch in series with the anode or closing a switch to short the anode and cathode together The latter method is the one used in the Third Ear but before getting any further into that there are a few easy modifications that must first be made to the S 210U The pictorial diagram shows the four necessary modifications in detail First remove the 5000 ohm trimmer by un soldering it This device is unusual in that it has two mounting pins not three Wire a 2500 ohm potentiometer in series with a 680 ohm resistor so that the net resistance is a minimum ELEMENTARY ELECTRONICS May June 1979 680 ohms when the pot is fully clock wise The two wires from the pot resistor combination should be solder ed into the holes vacated by the 5000 ohm trimmer This new pot will func tion as the Third Ear s sensitivity con trol with
129. aker switches and the touch plate are mounted on the PC board The polarity protection circuit may be wired point to point on a small chunk of perfboard and mounted on or near the car s fuse box in order to save space within the timer s cabinet Instead of using a cabinet especially if your car has a bit of room behind the dash you may wish to mount the timer s PC board right inside and have the touch plate and the switches mount ed flush on the dash in order to give the project that built in look How it Works ICI consists of two 555 timers one operating in a mono Stable mode and the other in an asta ble mode The monostable multivibra tor is triggered when your finger con tacts the touch plate It has a pulse length of 2 1 seconds when S1 is in the normal or closed position and about 5 2 seconds in the poor or open po sition The output of this circuit goes to the base of QI which serves as a differentiator inverter shaping the pulse into a positive sawtooth with a duration of 0 25 seconds The reshaped pulse is then fed to the reser side of the astable oscillator which operates at 600 Hz This oscillator will only produce an output when the reser input is held above ground potential minimum of 0 4 volts Therefore the oscillator will produce a 600 Hz tone for 0 25 sec onds which is fed into the speaker as the audible warning Operation After connecting the pro tection circuit to the fuse
130. alog The Faster and Easler Book Box 110Ce 72 Corwin Drive Painesville Ohio 44077 Tel 216 354 2101 TWX 810 425 2250 Faster and Easier is what we re all about CIRCLE 26 ON READER SERVICE COUPON ELEMENTARY ELECTRONICS May June 1979 27 go backpacking go trailering go fishing gorelaxing go adventuring but don t go outdoors again without CAMPING JOURNAL the 1 family outdoor recreation magazine THE MAGAZINE OF FAMILY ee Atoeeauors It s more than that It s the 1 passport to America s favorite recreation and the whole wonderful world of outdoor fun for you and your family Discover for yourself new and exciting places that get you away from day to day routine CAMPING JOURNAL is crammed like an overstuffed backpack with ideas for more camping FUN What to do Where to find it What kind of gear to get and how to keep it working right A great magazine Your kind When you re reading CAMPING JOURNAL you soon realize we re staffed with stone hard Camping fanatics See for yourself how much we can add to your favorite leisure time activity CAMPING JOURNAL Box 2620 Greenwich CT 06835 0 Send me 9 issues for ONLY 6 95 D enclose 6 95 O Bill me 6 95 Outside U S A and possessions 8 48 Name Address_ Please allow 6 to 8 weeks for delivery of first copy H9 D097 28 Electronics in the News Ceramic Braid In steel and glass plant furnaces and
131. alteur Aad Lic Sty Gde for Nov Teck amp Gen Ciass 336 p 6 95 1092 First Class Commercial FCC Lic Study Guide 378 p 20511 795 582 Commercial FCC License Handbook 434 p 150 7 95 652 2nd Class FCC Encyciopedia Study Guide 602 p 445 il 7 95 893 Third Class FCC License Study Guide 308 p 88 6 95 873 Ham Radio Novice Class License Study Guide 224 p 5711 595 851 Ham Radio General Class License Stuy Guide 448 p 7 95 827 Ham Radio Advanced Class License Sudy Guide 252p 595 43 Ham Radio Extra Class License Study Guide 224 p 162 595 989 Ham Radio Incentive Licensing Guide 154 p 70 495 CB COMMUNICATIONS HAM RADIO amp PHONES 1097 All About Telephones 192p 140 ii 1052 Radar Detector Handy Manual 80 p 83 1 2 25 1054 Antenna Construction Hdbk for Ham CB amp SWL 238 p 5 95 1005 Hdbk of Solar Flare Monitoring amp Prog Forecasting 196 p 6 96 495 s sm a i 1 SEMICONDUCTORS TUBES amp TRANSISTORS 1016 Towers International FET Selector 140 p 1010 Towers Inter T ansistor Selector 200 p 179 1 7 x 10 B56 Master OP AMF Applications Handdook 476 p 32011 960 IC Function Locator 224 p 984 CMOS Databook 280 p 270 11 870 Masle Tube Substitution Handbook 548 p 322 w 970 Master Transistr IC Substitution Handbook 518 p 165 il 717 Transistor Theory for Technicians amp Engrs 224 p 17161 938 Linear IC Applications Handbook 280 p 183 470 Transisior Circuit Guidebook 224 p 118 l 794 M
132. an As sociation for the Advancement of Sci ence the Smithsonian Institution of History and Technology the United States Park Service the Edison Na tional Historic Site in West Orange N J the site of Edison s research lab oratory Menlo Park New Jersey the city in which Edison conducted his successful experiments with the incan descent lamp the New Jersey Histori The celebration of the centennial of electric illumination will recall Edison s light and hopefully shed some on the process of invention for the youth of today cal Commission Fort Myers Florida site of Edison s winter home and for mer site of his Fort Myers Lab the Electric Power Research Institute the Edison Electric Institute and Rutgers University which is initiating a 20 year project to organize and publish all of Edison s scientific papers One major focus of Centennial ac tivities will be Dearborn Michigan where 50 years ago Henry Ford dedi cated Greenfield Village and the Ford Museum to American values and m genuity and to the man he considered to be the greatest genius the world has ever known Ford removed the 82 year old inventor s first laboratary board by board and mail by nai l from its Original site in Menlo Park and even transplanted alang with the re constructed building the actual earth from the building s front yard Edison s wry comment on seeing the rebuilt lab F MM
133. an extra cost accessory look me over Showcase of New Products Call for Echo An analog echo unit with no moving parts and a two position output level selector which controls signal strength for use either in home stereo systems or elec tronic musical instrument systems is the RolandCorp DC 10 This versatile unit provides a full range of effects from single delay to the recreation of sound CIRCLE 48 ON READER SERVICE COUPON as it might be heard in a large concert hall The lightweight model features stereo output and allows remote control of echo effect through an optional foot switch Single delays acoustic echo ef fects sustained echos and chorus ef fects similar to those achieved by a phase shifter can be achieved but all of them can be by passed by the foot switch which changes the effects in stantly to direct unaffected sound A three position input selector 20 35 50 dB makes it easy to accept nearly any kind of input The DC 10 analog echo unit sells for 390 For more info write to RolandCorp US 2401 Saybrook Avenue Los Angeles CA 90040 Three New Oscilloscopes Quick and easy set up and operation are the key features in a new line of push button triggered oscilloscopes introduced by Hickok They consist of three models which feature automatic triggering color coded front panels and conveniently grouped controls The Model 532 at 995 including probes is a dual trace 30 MHz
134. an hams and the CB lingo is now part of everyday English There s absolutely nothing wrong with using everyday vocabulary on the ham bands UNDERSTANDING AMA 4 PUBLISHED SY THE AMEWCAN RADIO RELAY LEAGUE These five ARRL publications comprise an excellent desktop reference series for the Amateur From basic principles of radio to the finer points of station operation these books are the answer to avoiding be coming what is known as a lid An out standing bargain even at twice the price That textbook grammar is strictly kid stuff One of the most efficacious methods of punching through on the HF phone bands below 30 MHz is to turn up your speech compressor to maximum The splatter will clear out anything within 10 kHz in either direc tion Let s face it if your phone signal is good within its limited 2 kHz band width it ought to sound five times as good with the additional space Don t give in to those guys who inevitably will ask you to detune If their rigs don t have enough receiver filtering that s their problem not yours The Strndean Amreteus Renee Communication 62 On Working DX Don t wait until that DX station finishes calling CQ before you start answering Start calling him as soon as you have his call down He may have a local frequency manager listening on the side who is taking down the calls of the stations answering the CQ in order to have a list f
135. ance Crystal Sets 10 plans 25 Hand book 18 Different 50 20 Different 504 Kit ee Laboratories 1477 G Garden Grove CA POLICE Scanners Crystals Antennas Radar De tectors CB s HPR Box 19224 Denver CO_80219 FOUR crystal radio plans and crystal diode 1 00 Henley 502 No Armstrong Pleasant Hill MO 64080 SCIENCE amp CHEMISTRY FIREWORKS Spectacular novelties Simplified manufacturers textbook 5 00 Tropic Box 95M Palm Bay FL 32905 TREASURE FINDERS PROSPECTING EQUIPMENT GOLD Silver Where to find it How to refine it P a phitemtark P O Box 671 Perth Amboy I WATCHES WATCHMAKING amp REPAIRING WATCH and clock repairing books tools materials Free Catalog North American Box 77 EE53 Fox River Grove IL 60031 WORK CLOTHES WORK PANTS 3 Coveralls 6 Postpaid Catalog 1 refundable with order Workmen s Garment Co 15205 DP Wyoming Detroit MI 48238 SAVE MONEY TOO BY READING and ANSWERING THESE CLASSIFIED ADS ELEMENTARY ELECTRONICS May June 1979 97 Never Stopped Pallishing Where is Whites Radio Log ta P D Powell River B C Keep looking White s Radio Log is a part of COMMUNICATIONS WorLD which is now published once a year The 1979 edi tion hit the newsstands in late January If you can t find a copy send 1 75 plus 25 cents for postage and handling to COMMUNICATIONS WORLD Single C
136. and all worked well up to 250 watts 1009 P E P rating is correct At the low We must assume the REDCO end we found flea power as low as 2 watts through the in line connection gave reliable performance While the in line connection has no effect at the lower frequencies in the range of 27 to 30 MHz it produces an SWR of nominally 1 3 1 This has no real effect on the average antenna sys tem or the associated transmitter s per formance but you should be aware of the fact your SWR indicator meter will read slightly higher than usual Is it Accurate Accuracy is always a relative term for it depends on what is used as the standard of reference In this instance we used a Hewlett Pack ard frequency counter which is gener ally employed for our transmitter tests The REDCO RFC 50 indicated within 20 Hz of the HP s reading Consider ing that the HP counter can indicate 0 001 Hz the RFC 50 s frequency read ing was essentially accurate certainly as accurate as the average hobbyist will ever need or be able to afford As to long term accuracy that depends as do all other counters without a TXO temperature controlled oscillator on the ambient environment and the qual ity of the counter s crystal and com _ponents E Summing Up Overall the REDCO RFC 50 performs well as an in line Adjacent channel rejection measured 65 dB con Y Amateur or CB frequency indicator The REDCO RFC 50 Commun
137. apsmit further give clearest rec ption Low S W R across 40 channels Non magnetic Tapered whip cuts 7 chrome plated 1 brass signal Fiutter ssteguards antenna tuning Hermotically Sealed high strength A B S housing protects against molsture and temperature and assures constant high performance Outperforms all top center or base loaded antennas tested including K 40 A S Firestik Hustler and Hy Gain WE GUARANTEE IT Solid copper coll windings delivers all the power your radio can transmit Sliver plaled connector mount strong low resistance consistent performance corrosion tree e p 6 0 78 6 2 ku o 28 a O ung seat prevents moisture and water leakage Get the facts See your Avanti dealer or write for details t AVANT antennas AVANTI RESEARCH and DEVELOPMENT INC 340 Stewart Avenue Addison IL 60101 312 628 9350 IN CANADA Lenbrook Industries 1145 Bellamy Scarborough Ontario MIH IHS CIRCLE 41 ON READER SERVICE COUPON NOWA oo Add on Mini Disc for the TRS 80 i Heavy duty 1 2 mounl deeply grooved NO Sirip threads can t pull loose Creators of the famous Moon rakers PDL II Astro plane Astro Beam Sigma Saturn Astro Scan Mobile Racers Dual and triple drives ji also available cent i as 3 amp Foy otto lt feos PRAEG w ha F Renae 4 a
138. ard oscilloscope in the lab of the local community college since a 10 MHz bandwidth was insuf ficient Construction At this point I would like to give two construction hints that I have developed and which were very helpful in building this kit There is a lot of detailed checking of very dense PC boards before and after soldering and for this I have always used a stamp collector s light with magnifying lens These can be purchased quite cheaply 53 QA sx at any philatelic supply store Also I use a soft nylon toothbrush to clean off the board after soldering to remove stray splatters of lead that can cause solder bridges It works quite well Assembly starts with the power sup ply It is self contained and very com pact The fan is much quieter than on other computers and is unnoticeable when the chassis is closed On the PC board a small modification had to be made to desensitize the crowbar cir cuit protecting against a power surge Interestingly a similar circuit was dem onstrated in Kilobaud Klassroom 6 There is very little point to point wiring as snap on connectors and two cable assemblies are included Amphe nol RF connectors are supplied and are of the highest quality All voltage tests were passed with honors The keyboard came pre assembled and I was disappointed at missing the chance to build it The store informed me that there had been too many con struction problems with it As
139. as screw ter minals it s possible that because of the extra high sensitivity of the Palomar 56 antenna a certain position s of the loop will cause feedback if the an tenna system is mounted directly on the receiver or immediately adjacent to the antenna terminals The feed back is evidenced either by receiver blocking or a loss of sensitivity in the receiver coincident with a whistle caused by self oscillation of the sys tem Simply moving the Palomar unit a foot or so away from the recciver will eliminate the feedback Set the loop antenna so there is no tilt as indicated by the 0 index of the loop assembly pointing straight down Set your receiver s tuning to a desired station or to a dead frequency where you believe a station to exist Switch on the loop amplifier and then adjust the loop amplifier s tuning knob for maximum received signal strength or noise If you tune for maximum noise readjust the tuning knob after you have a station tuned in Then holding the loop s metal bracket and not the loop itself rotate the loop assembly for maximum received signal strength If your receiver has an S meter you will see an increase in the meter read ing If your receiver does not have an S meter you will hear the signal in crease in volume only if it was very weak or not received without the Palomar If the signal was strong to start with you probably will hear no effect from the sp
140. ase suupiBold r w 98 advd uo panulju0 i Par gt S33ul anva SIG AZSUOd WWI L 5N3S aAgiy LSILUY LSIT GNVHH3O 3AV3T ISILUYY UANITHIY ur imos N M081V MATTIW JAILS LSILNV I ENIS SNVauNd 40 X008 NnglTV HATTIN JAILS LSILHV r UJUNI ELSILUV L SN3S i i L NASTY 33TTIM JAILS LSILHV Na Wovid NIS M m ewnety E NITWIdd3Z GIT LLSILHV 3IMVMW SNS GNV SIG WngIV LS AISWG AWWOL ELSILUY 3 Sq3ul NS ANVE SIG WNSTY AISIG AWHDL LSILHV TION LUVLS LIX3 OL JAVIT AdAL S9NOS ANY WNETVY LSILHV HH IN3 S a LUYLS GNYWWIJ 7 x ll1 ELUVLS HOLDIS 2 WV UDOUd FAVAT OL LIX C LUYLS 23S LISIT OL GAY OL 3LYddn SATI4 TIY 40 ONILSIT ILITdWOI U4 LSIT A 5N9S AG WARTY ANY LSILUVY FLYNT OL EN S WNETY AG LSILHV TiVvVI7 OL ungTv LSILuV AG SONOS ANY WNETY 3192321 OL LST LUV SJIYINI VLYT TVILINI HZINI JL LUVLS a i a w NOTLONOA A GNYWH 9 N A N A ESNOILINULSNI G3S3N 2 NH AGVIJ Y SAIMINE VLU TV3 IdAL ONTAOHS AHVHSIT 3ISnW 3 NANU ZTaNYS _ 2907 NIHL 8 dI SVS TLSILYV LNIHd SSO N3H L wieeS dI OZY JLIE S Ov 2109 11 Z N O dI _ L TNSI Sa TY ole GU3H Ot IWI LSIY b 9 Zi N 9N0S LONI ST OL1091 N I SINYN HAGNN G3LISIT WNETY ON INT dd S NIHIL aA AT N zZ eE OLE t SVE s LSI LUY INT Yd BISE NHL az Al 20c OLDE BSAC OLOOS A SN G Jl L ENSTI Sa TY BIA AVAY 1 ImMLSIY A EN INWYN
141. ate JIVMBO REO CLEAR i 40 CHANNEL CB BOARD POLY PAKS Terms Add Postage Rated Net 30 LED WATCH GUTS Phone 617 245 3828 Retail 16 18 Del Carmine St Wakefield Ladies P O BOX 942 N6 MA For ee Men s MINIMUM SO LYNNFIELD MA Factory ley arounds No pime Cat No 2 for 10 ORDER 8 ol cant a digital tE at No 92CUS11l5R he compiete m amt Ruts are hee so you gain Hy gain tn P tory close out from Mod Tran z ad mena and 49 apas Watt Amp pit ane used for 10 Buy 20 worth of merchandise HOURS MINUTES 4 rar Semi MM series M The SE ES aistorn and National Sem oe nerien o 10 n 73 Mag Choose any two 1 29 items FREE DATE SOS MON NTH and Frock meter cC onversion see amp ee s parts alane make it an Cat No 92CUSEBO ffer you cant re 2 for 1 50 l l i L CIRCLE 16 ON READER SERVICE COUPON ELEMENTARY ELECTRONICS May June 1979 91 P I CREATE YOUR OWN GOLD RUSH Create Golden Nuggets For Less Than 25 Each 1 500 1 00 postage and handling Jewelers Hobbyists For Fun or DO IT YOURSELF Instructions included Must be electroplated HI Use a toy railroad control doorbell battery or car battery charger aS a power source NOW You can build and electro form heavy abstract edges on any stone and create Jewelry pla
142. attery power ed radio wherever you go into the house or even outdoors to know what s going on inside Having problems with intruders Perhaps only the seasonal kind that splatter hard to remove raw eggs all over your patio bricks Put a mike out in the yard as an effective early warn ing system On the farm put the mike in the hen house to help catch that wiley four footed intruder that has been eluding capture for so long When you install that new TV an tenna take a portable radio up on the roof As you rotate the antenna an other person watching the TV screen down below can use the wireless mike to tell you when the picture is clear est And what about the housewife who can t bear to miss that next episode of her favorite soap opera yet absolutely must spend some time down in the laundry She can put the mike in front of the turned on TV and at least hear whether Mary will actually leave John to start cooking for Harry Countless other applications for wire less microphones relate to such broad activities as business leisure time ac tivities sports and education Use your system as a hot line tag sale communi cator public speaking aid or a secret prop during a magic show or other amateur theatrical performance ELEMENTARY ELECTRONICS May June 1979 You can even hook your receiver to a tape recorder to obtain permanent records of your personal transmissions Just plug the speaker output on your portable
143. back Two diodes The transistor has a very thin P region Two separate diodes wired back to back will not be have like a transistor Why this difference in construc tion should make the transistor act like a transistor and not like two diodes will not be covered as this is semi conductor physics and not electronics 79 What is the main construction difference between two diodes connected back to back and a transistor the very thin P region used in the transistor The three terminals of a transistor the base the emitter and the collector are connected as shown below re wee Fw Pee amp Fa eT oe Ree COLLECTOR BASE EMITTER The two diodes are usually called the base emitter diode and the base collector diode The symbo used in circuit diagrams for the transistor is shown on the following diagram with the two diodes and the junctions shown for Comparison Because of the way the semiconductor materials are arranged this is known as an NPN transistor Which transistor terminal has the arrowhead the emitter it is also possible to make transistors with a PNP con figuration as shown below pase P Both types NPN and PNP are made from either sili con or germanium QUESTIONS 4 Draw a circuit symbol for both an NPN and a PNP transistor Use a separate sheet of paper for your diagrams 5 Which of these might be silicon 6
144. c 7 Lower Ab again and get a new b 8 Measure and record all the values again 9 Continue this until Vc 0 V 10 Further reductions in the value of R2 will increase Ib but will not increase Ic or Vc Check the figures in your table to make sure you got a consistent pattern Then compare your measurements with the ones given a Seeger The figures in this table were obtained in an experiment conducted with considerable care Precision resistors were used and a commercial 2N3643 transistor was used With ordinary 10 or 20 tolerance resistors and a transistor chosen at random different figures will obviously be obtained So if your figures are not as precise as those here do not worry 8 1 volts 7 7 7 1 6 2 5 7 5 0 4 5 4 0 3 4 3 1 a 12 0 In the Uae which produced this table 8 100 You can see this by forming the ratio Ic Ib for almost every pair of current values For each value of Ib and its corresponding value of Ic in the experiment calculate the value of 8 The values wil vary slightly but will be close to an average Ex cessively low and high values of b may produce values of 8 which will be quite different Ignore these for now ELEMENTARY ELECTRONICS May June 1979 ee ee eee eee f Did you get a consistent 8 Was it close to the manufac turer s specifications for your transistor f In the experiment you meas ured the voltage level a
145. c San Diego CA 92103 FREE 1 000 LADIES PHOTOS World s largest Matrimonial Catalog Postage Handling 1 00 Inter contact Box 12 Toronto Canada M4A 2M8 JAPANESE introductions Girls photographs de scriptions brochure details 1 00 INTER PACIFIC Box 304 Sc Birmingham MI 48012 BEAUTIFUL MEXICAN GIRLS Correspondence Photos details free Latins Box 1716 DE Chula Vista CA 92012 BECOME ORDAINED MINISTER legally Free Lifetime credentials Use title Reverend Write ae of the God Within Box 015313A Miami FL 1 CANOE Camping on the Delaware America s newest Wild and Scenic River Canoes Rafts Kayaks Transport on 185 miles Portage free Family safe adventure Free Brochure Point Pleasant Canoe Outfitters Box 6 Point Pleasant PA 18950 TRADITIONAL home loving ladies seeking mar riage Rainbow Box 62E Stehekin WA 98852 RADIO amp TELEVISION TV TUBES 36 each Send for Free 48 page color catalog Cornell 4217 W University San Diego Cal ifornia 92105 TUBES Oldies latest Supplies components sche matics Catalog free Stamp appreciated Steinmetz 7619 EE Maplewood Hammond IN 46324 SAVE 50 build your own speaker system Write McGee Radio Electronics 1991 McGee Street Kansas City MO 64108 LINEAR Amplifiers 3 5 30 MHZ Schematics De tailed Instructions For Base BL 200 Mobils BL 100 am Paq All 6 00 Bomar s Box 541 Pendleton BUILD Dist
146. ced Applications for Pocket Calculators 404 p 275 i 538 Computer Circuits amp How They Work 192 p 1 amp 9 ii 574 Beginner s Guide to Computer Programming 430 p 364 l 785 Microprocessor Micropragramming Hdbk 294 B 176 709 Modern Guide to Digital Logic 294 p 222 1 724 Get the Most Out of Electronic Calculators 204 p 28 l 548 Beginner s Guide to Computer Logic 192 p 175 il BASIC amp GENERAL ELECTRONICS TECHNOLOGY 1 1006 8uild Book of Solar Heating Projects 196 p 111 il 5 T 97 Electric Motor 510 How to Read Electronic Circuit Diagrams 192 b 140 il 588 Basic Electronics Course 384 p 275 il 891 Practical Solid State DC Power Supphes 196 p 151 il 628 Basic Electricity amp Beginning Electronics 252 p 191 il 830 Introduction to Medical Electronics 320 p 126 il 655 Modern Electronics Math 686 p 424 l 728 Basic Digital Electronics 210 p 117 i 691 Electronics Unraveled 228 p 96 11 828 Switching Regulators amp Power Suppiies 252 p 128 il 83 Industrial Electronics Principles amp Practice 415 p 380 il 930 Servicing Medical amp Bioelectronic Equipment 350p 165 il 300 Dictionary of Electronics 420 p 487 l 601 Basic Color Television Course 420 p over 30 il 575 Modern Radar Theory Oper and Maint 488 p 253 il 104 Basic Radio Course 224 p 128 il 638 Marine Electronics Handbook 192 p 106 Il 528 Pulse amp Swiiching Circuits 256 p 184 i
147. cs New English Magazine A new maga zine titled Sounds Vintage is being published in Great Britain Sounds Vin tage is published bi monthly and is written expressly for those persons in terested in wireless and vintage sound Among the areas covered are vintage wireless equipment gramaphones and cylinder players disc record players vintage amplifiers and pre war litera ture In the future there will be stories of wireless pioneers and of companies involved in the manufacture of radio and wireless equipment The price will be 680 U K Eng lish Pounds send an International Money Order postage paid by air mail for a one year subscription of 6 copies Write to Sounds Vintage 28 Chestwood Close Billericay Essex England More On Test Equipment Many an tique radio collectors neglect one of the most interesting facets of the hobby These items are electrical meters and test equipment I first became interested in radio in 1931 and have earned a living since 1935 in the radio electronic field I have always been interested in electrical meters and have built most kinds of simple test instruments I built 74 This ts an I P 500 Crys tal Detector Receiver made in 1918 that was a prize winner in the old equipment contest at the AWA Confer ence in 1978 my first VOM Volt Ohm Meter in 1934 and my first tube tester in 1935 Since then I ve built capacitor testers signal generators VIVM s Vacuum
148. ct Set your Third Ear into the pulse mode with _ R5 set for a minimum duration and sensitivity control R placed at the mid point of its range of rotation Now turn on power switch S1 LED should flash momentarily as power is applied Snap your fingers directly in front of the microphone and note the length of time that LEDI remains lit Next rotate the duration control to maximum Snap your fingers and again make a note of how long LED stays ittumunated Finally turn the power switch off and flip S2 to the latch mode After five seconds re apply power Snapping your fingers should now cause the LED to light and stay lit for as long as power is applied You can do some experimenting with the sensitivity con trol too In the prototype operation at maximum sensitivity was impossible because even the faintest ambient noise would trigger the circuit The applications for the Third Ear are only limited to the uses your imag ination can find and with its switching flexibility it can control almost any thing you may wish to operate around the home or office ial ELEMENTARY ELECTRONICS May June 1979 have an image problem There are people who still think of wire less mikes as merely toys or party time novelty items while other folk invari ably associate these miniaturized elec tronic marvels with the nefarious bug ging activities of cloak and dagger CIA agents and with gum shoe private eyes pry
149. ctions Again proceed slow ly to prevent breaking the glass en velope If you break or crack the tube envelope start on another one one out of three is not a bad average If you choose a TV tube with a glass base 6LQ6 press the copper loop around the prongs and against the glass bottom of the tube Break off the small glass seal between the prongs and let air into the tube Heat up the soldering gun and rotate the tube until the glass cracks in a round circle Now break and crush the glass base with the wire tube prongs into little pieces Be very careful in removing the tube elements they must be reduced in size until all parts fit through the small opening You may want to cut and remove each element piece individually until all parts are removed from the tube envelope Later On you can glue this glass en velope over a separate bakelite tube base It s best to cut out three dr four tube envelopes After removing the tube ele ments choose the best one If the glass edge is a little irregular don t worry when placed upon the black base the area will be covered with rubber sili cone cement and will look like it be longed there all along Now wash out the white and dark areas inside the glass envelope Tube Base Preparation To remove the remaining glass and connecting wires from the tube base each tube prong must be unsoldered Hold the tube base upright and over a paste board box Apply heat from the sol
150. d near the antenna is unavoidable when adjusting the tuning coil When proper response was Obtained with the receiver during the tuning operation it was immediately lost when the hand was moved away Thus it appeared neces sary to tune in bits and pieces mak ing minor adjustments and then re moving the hand to see if the frequen cy was locked in properly The mike was tested first with an electret microphone and then with a crystal mike cartridge The crystal seemed to give somewhat better results although we did not succeed in getting performance comparable with that of any other wireless discussed in the above Sections Science Fair AM Broadcaster Ra dio Shack cat no 28 209 7 95 is the only AM transmitter found on the market The price includes everything you need except a 9 volt battery As sembly of the components on a 4 inch by 6 inch board requires no sol dering because all connections are made to spring type fasteners that plug into ELEMENTARY ELECTRONICS May June 1979 aii kA w O TaT q Eaa er 1 Or J t m le Q Radio Shack s AM Broadcaster costs 7 95 and includes everything except battery Circle 32 on Reader Service Coupon holes in the board The tuning coil is made by winding 34 turns of wire around a plastic frame measuring 3 inches by 4 2 inches which is then mounted vertically at one edge of the main component board The transmit ter utilizes a crystal m
151. d a low battery warning is included DC polarity is automatic with indication directly on the readout display Full details on the new Model 3300 DVOM and its complete line of accessories may be obtained at leading electronic distributors or write to Triplett Corporation Bluffton OH 45817 or call 419 358 5015 50 MHz Logic Probe Dynascan s new B amp K Precision logic probe is capable of measurements from DC to 50 MHz The new probe Model DP 50 is a multi family device that is compatib e with TTL DTL RTL HTL CMOS MOS and high noise immunity logic HiNIL Three bright LED indi cators display pulse presence and high p we CIRCLE 59 ON READER SERVICE COUPON _ 15112 59 and iow ogic states The DP 50 will con tinue to indicate pulse presence through its maximum frequency of 50 MHz For high speed or intermittent pulses the DP 50 offers a memory mode to freeze and store the pulse display In the pulse mode short duration pulses are stretched for a clear visual indication Input impedance is 2 megohms in all modes The DP 50 is overload protected and will withstand 50 VDC at the in put Reverse polarity protection for the power leads is also 50 volts Sells for 50 00 For additiona information con tact B amp K Precision 6460 W Cortland St Chicago IL 60635 Two Meters ina Fist The YAESU amateur radio hand held transceiver Model FT 202R provides 1 watt
152. de automatic indexing for 7 10 and 12 inch rec ords At the end of each play the tone arm returns to the rest and power turns off unless the repeat play button is used The tonearm can be operated manually if desired The vertical tracking force is adjust able in 0 1 gram increments from 0 to 3 grams and there is a calibrated anti skate adjustment The turntable speed is unaffected by line voltage variations between 90 and 140 volts The 33 RPM Hey Look Me Over Continued from page 18 i CIRCLE 56 ON READER SERVICE COUPON Ld included Get all specs direct from YAESU Electronics Corporation 15954 Downey Avenue P O Box 498 Paramount CA 90723 m ELEMENTARY ELECTRONICS May June 1979 the pitch control could be varied 5 4 per cent and 7 percent and the 45 RPM pitch control could be adjusted 3 percent and 5 percent Wow and flut ter measured 0 05 percent with peaks to 0 12 percent Output cable capacr tance is a nominal 90 pF The listening panel felt that the sound quality of first rate cartridges was noticeably improved with this turntable Everyone who has tried the KD 5070 has been impressed with its ease of operation With the automatic features all you do is put a record on the spindle and push the start button You never have to touch the tonearm It s great if you need a turntable that can be used by children The KD 5070 carries a suggested retail price
153. de switches When a toggle is snapped quickly the click of the switch can activate your system regardless of the sensitivity set ting Slide switches require very little operating force and are practically si lent The contacts of relay K1 are rated for a load of up to one ampere which is more than adequate for most appli cations Sometimes however you may wish to control a high power load such as a flood lamp One method of doing The Third Ear can be adjusted so that it triggers and holds or so that it triggers and resets This chart shows how the output level varies with in coming sound pulses this would be to substitute a relay with a higher contact rating for K1 but high current good quality relays are expensive Besides that all relays arc especially with high power loads so a relay s lifetime under such conditions is limited A cheaper better solution is the high power interface Note that the triac controls the AC load but the relay contacts control the triac In this way the relay contacts carry only the small gate current of the triac and your Third Ear remains isolated from the AC line and shock hazards by the relay Choose a triac with a current rating high enough for your load and heat sink it Mount the triac and heat sink in a well ventilated plastic case to prevent accidental shocks Checking it Out After construction is complete you should check out the operation of your proje
154. deed some of them did just that as witness the development of laser technology plas tics television and computer science to mention but a few of the more obvi ous examples Scientific progress con tinues to be made of course but some thing is clearly missing It s the unique kind of inspired motivation that char acterized Edison and other scientific greats of the past A year long Centennial of Light an international celebration to com memorate the 100th anniversary of Thomas Edison s invention of the in candescent electric light bulb on Oc tober 21 1879 has a second and equally important purpose To inspire the youth of today and of the future in the belief that there are solutions to many of today s global problems The solutions need only to be sought and found through scientific developments Tiss ALVA EDISON was one of a as well as through social political and economic advances Thomas Edison a highly principled inventer businessman is the ideal in spirational symbol As Robert I Smith chairman of Public Service Electric and Gas Company and head of the Inter national Committee for the Centennial of Light paraphrases an Edison biog raphy Although Edison led no armies conquered no countries enslaved no people his life and his inventions have influenced the course of history more than any other person in recorded civ lization The light bulb was but on of more than 1 000 inv
155. der s Guide Now with the over 100 projects contained in The ABC Book of Hi Fi Audio Projects by George Leon anyone can boost the capability and performance of any hi fi audio system or build a complete system from scratch if preferred Each project is accompanied by a complete schematic wiring diagram and a detailed parts list Many have PC board lay outs ready for photo pickup n this learn as you build volume the reader will find out how to design his own circuits how to create new audio power supplies how to build amplifiers how to use timer circuits how to make mockups of chassis layouts and control panel designs how to construct The ABC Bock oi Hi Fi An Gio Do It Yourself Hi Fi construction projects Soft cover 182 pages 4 95 SERVICE COUPON enclosures how to make mixer circuits how to make printed circuit boards how to build preamplifiers how to modify and fu CIRCLE 55 ON READER turize his system in hundreds of ways And one doesn t have to be an electronics whiz kid either even a beginner can follow these simplified instructions and explanations and then customize to his heart s content Published by Tab Books Blue Ridge Sum mit PA 17214 l Optofun Optoelectronics the world of light lasers lenses and sicence fiction de vices a world that s completely unfolded in Optoelectronics in an illuminating package Soft cover 238 pages 5 95 CIRCLE 55 ON READER
156. e This DXer s delight can pluck a flea powered station right out from under the nose of a clear channel giant dead part of the broadcast band flip a switch and suddenly find it s jam packed with stations That s exactly what happened to us when we tried the Palomar Engineers BCB Loop Antenna System We connected everything together the loop antenna system and a budget receiver set the dial to the high end between stations so we could hear how the loop antenna first affected the re ception of interstation noise We ex pected the noise would give us some idea of whether the antenna system ac tually had gain Problem was the instant we flipped the antenna system s power switch on the radio was no longer tuned to a dead spot rather we got a signal booming in like the transmitter was out the back door Tuning the receiver told us we were not going to find any dead spots because the high end was filled with DX we d never heard before To make certain some unusual skip condtion wasn t playing tricks we turned off the Palomar loop antenna system and the high end went almost dead as the proverbial doornail Where we had heard S3 to S7 signals we could no longer hear anything but noise there wasn t a trace of a signal even with the receiver s BFO turned on Talk about digging out signals from H WOULD YOU LIKE TO tune to a y under the noise The Palomar loop an r Palomar E
157. e ments or boom thus providing extra strength The suggested list price of the Model ST 5 is 39 95 The Model ST 11 is 59 95 For further information on these or any Hustler products write to New Tronics Corporation 15800 Com merce Park Drive Brookpark OH 44142 Hand Held CB A 40 channel hand held CB transceiver the Dyna Com 40 made by Lafayette Radio is a full powered unit priced at 149 99 The Lafayette Dyna Com 40 in corporates full five watt input at the final amplifier with an LED light emitting diode channel indicator and digital Phase Lock Loop PLL circuitry Other features are a full time range boost circuit that concentrates more audio power into the sidebands for greater transmission range squelch control au tomatic gain control automatic noise CIRCLE 45 ON READER SERVICE COUPON limiter S RF power meter battery con dition indicator and an external micro phone input jack Lafayette Radio Elec tronics Corp sells nationwide through 140 company owned stores an extensive direct mail operation and nearly 300 as sociate stores and authorized dealers What You See is What You Get Sparkomatic s new car stereo graphic equalizer booster amplifier enables the traveller to see the amplifier response shaped by the various tone controls on the unit The AcoustaTrac GE 500 pro CIRCLE 50 ON READER SERVICE COUPON duces a visual response curve on an illuminated screen which gra
158. e Consulta tion Service Certificate of Merit and Discount Privileges You receive all parts tools instructions etc Everything is yours to keen PRINTED CIRCUITRY At no increase in price the Edu Kit now includes Printed Circuitry Yau build a Printed Circuit Signal Injector a unique Servicing instrument that can deteet many Radio and TV troubles This revolutionary new technique of radio construction is now seroma popular in commercial radio and sets ie A Printed Circuit is a special insulated ADDRESS TT chassis on which has been deposited a con ducting material which takes the place of wiring The various parts are merely plugged In and soldered to terminals Printed Cireuitry is the basis of modern Automation Electronics A knowledge of this subject is a necessity today for anyone in terested in Electronics CIRCLE 14 ON READER SERVICE COUPON These are not unprofessional t FF F Guy amp STATE oaks yee PROGRESSIVE EDU KITS INC 1189 Broadway Dept 596 DJ F Reg U S 4 a Pat Off FREE EXTRAS SET OF TOOLS SOLDERING IRON ELECTRONICS TESTER PLIERS CUTTERS VALUABLE DISCOUNT CARD CERTIFICATE OF MERIT TESTER INSTRUCTION MANUAL HIGH FIDELITY GUIDE QUIZZES TELEVISION BOOK RADIO TROUBLE SHOOTING BOOK MEMBERSHIP IN RADIO TV CLUB CONSULTATION SERVICE e FCC AMATEUR LICENSE
159. e actually extracted a skywave signal out from under the sideband interference of a local station by simply nulling out the local It really works The nulling can also be used to re duce or eliminate local electrical in terference Say the motor or ignition system on your neighbor s oil burner or a faulty flourescent light is giving you broad spectrum noise hash all across the band Under certain condi tions it doesn t work every time you will be able to null out the electrical Interference We even got rid of the hash generated by a sewing machine motor in the next apartment Summing Up If you already have a longwire outdoors there will be little if any advantage unless you can util Continued on page 86 ELEMENTARY ELECTRONICS May June 1979 CIRCLE 52 ON READER SERVICE COUPON e e assembles the Heathkit AD 1304 Audio Processor Hi Fi add on stretches your system s dynamic range and filters out some unwanted noises HERE ARE CERTAIN CONDITIONS when E dynamic range of recordings or live broadcasts is limited to prevent ovcrmodulation of the recorder cr transmitter There are also times that a relatively high background noise could be obtrusive For the stereophiles fcr whom the occurance of dynamic range limiting or background noise might prove annoying the marketplace offers several types of audio processors which expand the dynamic range and or re duce high frequency background
160. e collector current ee ab The mathematical formula for current gain is as follows z E B Tb i where J base current C collector current From this you can see that if no base current Miia no collector current will flow And if more base current flows more collector current will flow This is what is meant when we Say the base current controls the col i lector current I Suppose the base current is 1 mA and the collector current is 150 mA What ts the current gain of the tran SO SMA See KPY v 150 x Current gan is a physical property of the transistor Itsivalue can be taken from the manufacturer s published data sheets or it can be determined experimentally by the user In general 8 is a different number from one transistor type to the next but it remains constant for a given tran sistor Transistors of the same type have 8 values within a narrow range of each other One of the most often performed calculations in tran sistor work is determining the values of either collector Or base current when 8 and the other current are known For example suppose a transistor has 500 mA of col lector Current flowing and it is known to have a value of 100 Find the base current To do this use the formula as shown below te P Ip IC _ 500 Ib B 100 5mA L Now you do these simple examples QUESTIONS IA eS A p 20 Find iby em l E Ra il Y 82 ku mn ja 1
161. e time delays between 9 and 130 sec to discharge complet ly thus ensuring time delay elapses the same procedure onds The actual control range obtain that the circuit will be inactive when applies ed in your model is likely to be some SI is again closed Similarly should In the prototype s pulse mode dura what different because of variations in you wish to manually unlatch the tion control R5 was able to produce the characteristics of Q3 and C3 Fur f ELEMENTARY ELECTRONICS May June 1979 38 Train with MicroComputers digital nA vai ERII con Og rent Css e The world of electronics is daily becoming more challenging Technology is growing more specialized and the importance of digital systems increases every day Test instruments home entertainment units and industrial control systems are all going digital And now NTS training programs include a wider choice of solid state and digital equipment than ever before offered in any home study course Advanced NTS Heath digital color TV 25 diagonal with optional programming capability NTS Heath microcomputer digital test equipment digital stereo receiver 70 watts per channel NTS compu trainer plus much more state of the art equipment to make your training exciting and relevant The equipment you receive with NTS training programs is selected to provide you with a solid NTS for the the first name background in electronic sys
162. eaker or headphones because the receiver s AGC automatic gain control will absorb the extra gain by reducing the receiver s gain an amount equal to the gain provided by the Palomar system Now assume the DX station you want to receive is adjacent to the fre quency of a strong local broadcaster To null out an inter fering groundwave signal the loop can be both rotated and tilted Skywave signals are not affected when the loop is tilted Loop tilt can also be used to reduce many forms of local electrical noise interference ee Epam eaen This ts where you use the null feature Remember nulling only applies to a groundwave signal you cannot null a skywave in order to receive another skywave One of the easiest ways to null is to first peak the Palomar to the unde sired local signal then rotate the loop for minimum reception followed by adjusting the loop s tilt for additional null With a little practice you can simultaneously adjust position and tilt to almost instantly null a station The null is very deep we have virtually eliminated all traces of a local broad caster using a completely shielded Palomar to receiver input connection When the receiver has screw terminals some signal will be picked up by the screw itself and the short length of unshielded coaxial wire connected to the screw but the pickup will be in significant The null is exceptionally deep and we hav
163. eally should have a service shop align the frequency syn thesizer so your transmitter s carrier is as close to the channel frequency as is possible While a frequency counter is prob ably the most reliable way for the hob I THIS DAY AND AGE there is virtually 50 pen Front panel of the REDCO RC 50 contains a six place 0 3 inch LED display the power resolution selector and a 50 ohm direct connection to the counter The 10 and 100 resolution settings mean multiply the reading by 10 or 100 for the frequnecy in Hz EE mw p m j Walisldiz Eschanira Danya Lguanpusty Vi anh i ya ee ret gt ha kati gt A mak arp nam ton pl E S wama ae RLE The rear apron has a dual voltage power connector and an in line sampler con nection for the transmission line The as sociated power cord automalically switches the power supply for 120 VAC or 13 8 VDC operation The in line antenna connection will accommodate transmitters on all fre quencies to its upper limit of 40 MHz byist to check transmitter frequency using one can often be a first rate headache for few are sufficiently sen sitive to sniff the carrier leakage through the transmitter cabinet or receive the signal with a short antenna The way to get reliable full time measurement of the carrier is to have the counter work in line through a transmission line sampler
164. ed News About Britain and reports from BBC correspondents in fifteen minute Radio Newsreel pro grams World News Roundup In addition to major wire services such as the As sociated Press United Press Interna tional and Reuters the BBC uses as a news source its own radio monitoring service Located at Caversham Park about 50 miles from London its pro fessional SWL s listen to over 400 news bulletins from more than 30 countries every day But BBC programming isn t all news Of special interest to DxXers is the World Radio Club now boasting in excess of 30 000 members Meetings of the BBC sponsored organization are held on the air weekly The best time for North American listeners to hear these electronic conclaves is 2315 GMT 6 15 p m EST on Wednesdays The sessions are repeated at 2100 GMT 4 00 p m EST on Fridays Member ship is granted free of charge to any one who writes for it Long a favorite of shortwave buffs retired BBC engineer Henry Hatch currently conducts monthly instruction al talks called Radio for Beginners on the club programs Also featured are reports of stations heard by noted DXers and what the pros at Caver sham are hearing Listener Envolvement Every month colorful pennants are awarded to 25 lucky listeners who correctly answer a question posed by Mr Hatch Subjects of recent queries have included such topics as elementary electrical math the internati
165. ed in a U S Patent awarded to scientists at IBM s San Jose Research Laboratory Based on a photochemical process called hole burning the tech nique greatly increases the amount of information that can be packed into a given space In the system described by the pat ent each unit called a bit of com puter data is identified by its location in the frequency spectrum as well as by its location in two or three dimensional space Potentially many hundreds or even thousands of the frequency coded bits could be stored at a single microscopically smal region in space The size of these regions could be as small as the diffraction limit of a laser beam a dimension in the order of one micrometer 1 25 000 of an inch The invention depends on the use of a laser that can be tuned like adjusting the station selector on a radio so that it emits light of various colors IBM research scientists have invented a new approach to storing computer data that uses a variable color laser beam to induce chemical changes in selected mole cules of a storage material By changing the frequency of the laser light it becomes possible to select many hundreds or thou sands of different molecular groups from the same sample of storage material Each molecular group can be associated with a unit of computer data This technique called photochemical hole burning of fers the potential for storing data at much
166. eeg Ei Gal TOHEA SC A a ln ini a di 20 23 Howard Sams QA KM O m S m es ee lo Worde ee are a0 12 Information Unlimited 89 13 Iptesmatienal Crystal meiner ER s u U tents 26 Ew eran Ff h L A k Am EA a 32 National Technical School 38 41 ee i i M S Ub u m oa 26 Se MANE SCO OE a Su casas l Aerie 10 13 29 OK Machine amp Toal a ra esee aata A 31 oo RS ae eee or t 322 sa 890 18 15 Percom Data eee R AA tate I E i 14 WE Spo yspakspa ar nn lt a 1 91 14 Progressive Edu kits Inc a a 15 17 Quimtronix pee aqp Waska eee 89 P R adigs a a Q K S b L T CV4 I Radipsorpae kal 0 n 8 ua A Saham 11201 29 20 EShakespeane l tU o a l mal sl el 1 18 Southwest Technical M a r aiie iener ia 18 PO P ET E o A A S AN ee 3 9 Er l It s not what you think 98 Got a question or a problem with a project ask Hank Please gil that Hank s column is limited to answering specific electronic project questions that you send to him Personal replies cannot be made Sorry he isn t offering a circuit design service Write to Hank Scott Workshop Editor ELEMENTARY ELECTRONICS 380 Lexington Avenue New York NY 10017 B R Bracebridge Ontario And a happy anniversary to you You are a charter reader as I am We ve come a good many years and saw the de
167. ef Julian S Martin Managing Editor Alan H Rose K2RHK Technical Editor Gordon Sell KBDA1464 Associate Editor Lee Lensky KA2DKT Citizens Band Editor Kathi Martin KGK3916 Editorial Assistant Cynthia McClean KBKF3780 Workbench Editor Hank Scott Art Director Ralph Rubino Associate Art Director David Pindar Assistant Art Director Michael Vessio Cover Art Director Irving Bernstein Art Editor Joe Groom Art Assistants Celeste Barbera Leslie Wallant Delia Nobbs Advertising Director Ralph Vega Production Director Carl Bartee Production Manager Carole Dixon Production Assistant Annette Simon Newsstand Circulation Director Don Gabree Subscription Circulation Director Robert V Enlow Subscription Circulation Manager Eugene S Slawson Marketing Director James C Weakley President and Publisher Joel Davis Vice President and General Manager Leonard F Pinto Vice President and Treasurer Victor C Stabile KBP0681 ISSN 0013 595X ELEMENTARY ELECTRONICS is pub lished bi monthly by Davis Publica tions Inc Editorial and Executive of fices 380 Lexington Ave New York NY 10017 all subscription orders and mail regarding subscriptions should be sent to P O Box 2630 Greenwich CT 06835 In U S A and possessions one year subscription six issues 6 95 two year subscription 12 is sues 12 95 three years 18 issues 18 95 and four years 23 95 Else where add 1
168. electronic enter tainment equipment available now or in the near future And because NRI has unmatched experience gained in over 60 years and a million students worth of training your course is designed for ease of learning and practical utility You need no pre vious experience of any kind Starting with the basics exclusive bite size les sons cover subjects thoroughly clearly and concisely Hands on experiments reinforce theory for better comprehen sion and retention And your personal NRI instructor is always available for consultation ready with explanations answers and advice Send for Free Detailed Catalog No Salesman Will Call Get all the facts on this exciting course and its potential for you by mail ing the postage paid card today Our free 100 page catalog includes color photos of all kits and equipment complete lesson plans convenient time payment plans and information on other elec tronics courses You ll also find out about NRI s new Computer Technology Course that includes WE your personal microcomputer Or Complete Com munications with 2 meter transceiver that gets you ready for opportunities in broadcasting 2 way radio microwave and other growing fields H card has been ni write to NRI Schools McGrav Hill Continuing Education Center 3939 Wisconsin Ave Washington D C 20016 yk 13 The mobile mo nraker by Avanti a Avanti engineered to tr
169. embled Don Lancasters Cheap Video concept allows almost unlimited options SHO including 9 59 Scrolling Fullperformance cursor Line Character formats of 16 32 24 80 32 64 or almost anything Graphics up to 256 X 256 B amp W 96 X 128 COLOR requires low cost option modules Works with 6502 6800 and other micros SPECIAL OFFER Buy the Kit upper case alpha numeric option included amp get the Book at 1 2 price ERA ELECTRONICS 1020 WILSHIRE BLYO OKLAROMA CITY OK 73116 Se ee eae SS a SBE eS ee ween G G G GR G 4 s a ws 1 I Tm Sold PLEASE RUSH SEND FREE CATALOG I I I TVT 858 Kit amp Cheap Video Cookbook 42 95 enclosed I TVT 658 Kit only book required for assembly 39 95 pah ELECTRONICS ofP7 5 E 1020 W WILSHIRE BLYO ORLANOMA CITY OK 73116 poles Southwest Technical Products Corporation city state zip 219 W RHAPSODY J SAN ANTONIO TEXAS 78216 CIRCLE 28 ON READER SERVICE COUPON HEY LOOK ME OVER The new DVOM sells for only 175 00 complete with long life Ni Cad batteries and AC Adaptor Charger plus test probes with safety boots The Triplett Model 3300 is a safety conscious design with no exposed metal parts and it includes a high energy 2A 600 V fuse for ample overload protection A fused probe pro vides for both high energy and normal use circuit protection Over range is in dicated by a blinking display an
170. emory that did not interfere with other machine operations Our address designations merely reflect the sequential order of the program To load it we must first load the prc gram counter with the starting address then press RUN The machine then i takes bver driven and timed by the system clock It should be noted that our example was an addition routine This was be cause practically all the computer does is add with binary subtraction being merely a modified form of addition For example multiplication can be thought of as the successive addition of one number a certain number of times One illustrative but inefficient way to do this in machine code for 5 Xx 8 would be to clear the B register and put 5 into the A register We then add 8 to the B register 5 times each time we add 8 to the B register we subtract from register A There is an instruction that looks for a zero condition in the A register When this is the case we have added 8 five times or multiplied 5 x 8 For programmers wishing to use ma chine instructions it is not necessary to memorize all the binary number as sociated with the machine instructions Hi Fi Reports Continued from page 32 perior to the bulk of the units available While the KD 5070 is described as an automatic turntable it will not play a stack of L P s but it will deal with individual albums at the touch of a button The controls provi
171. entions patented by Edi son Other outstanding inventions in cluded An entire system of electric generation and distribution the phono graph the motion picture camera and equipment that made telephone and telegraph systems commercially prac ticable Edison s scientific genius had direct bearing long after his death on the cevelopment of the modern elec tronics world as we know it including invention of radio television and mod ern cinematography The Centennial of Light kicked off in September 1978 will go on through ELEMENTARY ELECTRON CS May June 1979 U S Department of the Interior Edison National Historic Site x P y I Es out 1979 Major elements of the plan ning are designed to attract students and educators For example symposi ums will bring selected high school students and teachers to Florida s Dis neyworld in February and university students and professors will go to San Francisco in April Science Fairs will be encouraged in elementary and high schools through out the country Educational materials and scholarship programs will empha size the need to encourage young peo ple to pursue scientific knowledge Other plans in the works include The showing of special films television and radio programs traveling exhibits dis plays and lectures and even parades Amonzg those already planning spe cial programs events and activities for the Centennial are The Americ
172. eo interface board The VB2 has its own keyboard input port so there is no need for another I O board for either keyboard or video display The hard ware controlled cursor for line feed carriage return back space and clear screen frees up valuable memory space The display is 64 by 16 and features all upper case letters Ce aii IQ CIRCLE 44 ON READER SERVICE COUPON as well as numbers and symbols and is switch selectable for white on black or black on white VB2 is available in kit form priced at 149 95 For further information contact SSM 2116 Walsh Avenue Santa Clara CA 95050 Prototyping Board A new prototyping circuit board bus and shape compatible with Altair and Imsai microcomputer boards holds up to seventy 14 or 16 pin DIPS or any combination of DIP sockets with 0 3 0 4 0 6 or 0 9 inch lead spacing De signed by Vector Electronic Company as their ANY DIP _Plugbord the Model 8804 board s convenient power and ground plane network makes it ideal for homebrew com puters or custom interface construction The 5 3 inch by CIRCLE 46 ON READER SERVICE COUPON 10 inch by 0 062 inch board has 100 50 each side card edge contacts on 0 125 inch centers to accommodate an S 100 bus organization Two 100 hole rows of individual QO l inch spaced pads across the top of the board permit additional input output via ribbonwire assemblies inex pensive wrap posts may be fabricated by inserting Victor
173. er dial pme e a ee E ur sm 1i ry ig k B This is the heavy duty battery powered round radio re erred to in the text that was made for use in Rhodesia in the 30s ELEMENTARY ELECTRONICS May June 1979 L z a Nam s wa ij s NO N S i am a A a A i k aq E r AF 1i e a u gt a i a i a iuaN l i drive The cabinet is deep drawn from aluminum Radia Phonographs There seems to be a group of collectors who are jook ing for the radio phonographs that were made between 1926 and 1931 Most collectors don t have room for these large console radios so the price hasn t shot up as has the older smaller battery operated radios I received a letter recently from a collector who is looking for several of these old radio phonographs I was surprised to learn that one model of RCA had a Radiola model 17 radio along with a wind up 78 RPM single play turntable in a high boy console cabinet Likewise Wells Gardner built a radio phonograph for Lyon amp Healy a large Chicago music store that had an AC operated radio in a lowboy phonograph cabinet with a hand wound record turntable The above named radio phonos all had elec _tric pickups to recover the sound from the records I recall a Majestic highboy that had both an electric turntable and an electric pick up This set was the model that used a five gang tuning ca pacitor and used type 26 s 27 s 45 s and a B supply setti
174. ers By W Barden Jr Examines assembly language programming of 8080 MC6800 amp MCS6502 models Ex plains concepts operation amp architecture With precanned operations 256 pgs 21459 8 95 Fundamentals of Digital Computers 2nd Ed By D Spencer Explains Computers programmin asa ware BASIC FORTRAN amp COB lan guages advanced concepts amp ee center operation 320 pgs 21534 9 95 The 8080A Bugbook Microcomputer interfacing and Programming By Rony Larsen amp Titus Emphasizes the computer as a controller Covers principals amp 4 basic tasks of computer interfacing BUGBOOK is a registered trademark of E amp L Instruments Inc Derby Conn 06418 416 pgs 21447 10 50 p a 5 3 s ap won n acsoceiTe r DBUG An 8080 Interpretive ger By C Titus amp J Titus How to use DBUG a software debugging package to develop amp test programs With documented hexadecimal amp octal listings 112 pgs 21536 4 95 introductory Experiments in Digital Electronics and 8080A Microcomputer Programming and interfacing By Rony Larsen amp Titus Covers basic gates thru microcomputer inter rupts with hardware amp software examples Experiments re breadboarding circuits etc over 416 pgs each Book 1 21550 12 95 Book 2 21551 10 95 Both 21552 20 95 NCR Data Communications Concepts By NCR Corp Explores concepts techniques amp limitation
175. ers feel that their products never need servicing Once the construction was finished I had sone difficulty loading BASIC from a cassette and my VDM had a nervous breakdown during the burn ing in period At this point I found the service at the Computer Place where I had bought the kit to be ex cellent and the fault was detected and repaired in just over a week I learned a great deal about com puters by constructing one and found the experience a lot of fun As a hard ware man I have many plans for the future of my SOL I am planning a circuit to create a typing sound when information is entered on the key board and a bell sound at the end of the line Heathkit already uses such a circuit and it makes data entry easier for a person used to a standard type writer I also plan to build the modem described in the November 1977 issue of Kilobaud Always remember that as long as you are still building you can counter the inevitable question of But what s it good for with the an swer Well just wait until I have everything finished You never will m ELEMENTARY ELECTRONICS May June 1979 E _ OUIV_ Ca d OM i iama Q Q o Palomar Engineers w 2 e e checks out the Loop Antenna a Pak ianiai ii z oe x EE E ias i re x oS ee ON READER SERVICE COUPON foto E 3 Ti ENE gn Ar g m PA a iss p E ri Pr m RB Palomar Engineer Loop Antenn
176. es scanning by pressing the appropirate pad button Programmed Scan Here s how you might utilize the computer Assume you have four active assistance channels in your area 9 10 11 and 19 You could program only these channels into the 10 channel memory and the com puter would scan only these four chan nels stopping on the first one to be come active If you had to shift im mediately to channel 9 let s assume you have just received an emergency call on 19 you could do it by simply pressing the 9 EMR 9 emergency pad button You can start stop or resume the scan Continued on page 88 75 a DAK MARK V e GENERAL ELECTRIC 3 5875 e MOTOROLA CB 555 s SBE KEY COM 1000 ELEMENTARY ELECTRONICS has been able to obtain some the latest 40 chan nel CB transceivers for review and pre sents the test reports here These units are not prototypes but are stock standard the same as the transceivers that you can buy over the counter If you don t find the particular unit you are interested in reported on here check for the 1979 edi tion of CB Buyers GUIDE soon to be on the newsstands e DAK MARK V 119 95 M H Scott General Description A 40 channel AM transceiver for mobile and P A operation Delta fine tuning 2 5 kHz is provided Power supply is 12 to 13 8 VDC with negative or posi tive ground Overall dimensions are 244 in H x 7 in W x 9 in D There are front pane
177. et out over the top of nearby interference power down to ensure superior performance and low SWR Big New Bonus in Reach and Range TIP LOAD the top loading coil is com pletely encased in Shakespeare s exclusive fiberglass process No bulge No lump No exposed coil And the sleek thin design stays erect at highway speeds BASE LOAD the Shakespeare base loaded coil is your booster promising extra per formance and delivering a true power match Twc Load Antenna Sty 5030 1B Trunk Lid Vouat with Duo Phased loading TB cee ANoaaa i ny AIRIS d III i fil PLUS the new sculptured chromed trunk mount that has Detroit chee ing With built in electronics A moulded rubber shield to protect your car s finish And the new Spin Off On Feature lets you laugh at the guys at the car wash The stud is stainless the housing sealed making the entire unit moisture proof and completely corrosion resistant Fk SEE Uyay ELECTRONICS AND FIBERGLASS DIVISION Antenna Sroup P 0 Box 246 Columbia S C 29202 The Shakespeare Company Manufacturers of Communications Antennas Marine Electronics Fishing Tackle Industrial Fiberglass Lighting Poles Wonderthread and Specialized Monofilaments Golf Equipment Automotive Products Saddlery and Equestrian Accessories 1979 The Shakespeare Co CIRCLE 20 ON READER SERVICE COUPON 1 THE STAFF Editor In Chi
178. ever SBE has some heavy competi tion in the field the Pace 8117 by Pathcom A real honest to goodness computerized CB transceiver The Pace 8117 is basically a base sta tion with provision for operation off a 13 8 VDC power source the DC cable is not supplied The rig features the usual 40 channel coverage PA and re mote speaker jacks an LED digital channel display S RF output meter et oe a ee ee 7 ET sas Ba L I RF gain control Delta tuning and the computer The Computer The computer is pro grammed by a 4 by 3 12 position touch pad such as you would find on a touch tone telephone Ten of the but tons are dual function numerals and commands so there are effectively twenty two operating keys which pro gram the computer The instant power is applied the com puter tunes the rig to channel 19 If you want to change channels there are fast and slow up down selectors that step through each channel If you want to go directly to a particular channel you can do that too Now none of these features really requires an on board ka ELEMENTARY ELECTRONICS May June 1979 4 S i r a CIRCLE 64 ON READER SERVICE COUPON i SP ES sp Dual purpose touch switches provide 22 alphanumeri func tions The numerals are for keying in the channel num bers the alpha designations are the computer func tions for example Cl M means clear memory MEM means p
179. f Electronics Inc 1776 East 17th Street Cleveland Ohio 44114 Accredited Member National Home Study Council g YES Iwant the best of everything Send me my FREE CIE school of home study information Print Name__ o EE RPE aea catalog including details about troubleshooting courses plus my FREE package EL 10 MAIL TODAY 1979 Check box for G I Bill information L Veteran Address _Apt City State PTPP S Zip Ag E Phone area code S _ Active Duty Completely pre assembled and pre tuned Just take it outof the package and install it on the car No tuning necessary check it out with a watt meter and see for yourself 60 Stainless steel tapered whip F a x PY 1 4 4 and NO spring __ There s a Coil in the cup Super good looking low silnouette design Your choice of cup colors design coordinated to Iqte moedel cars SIERRA kah A FIRE BRONZE E ATLANTES FIRETHORN E RED SNOWCAP WHITE CLASSIC SILVER AS SHOwN AND CRYSTAL CLEAR Magnet Thesenew Persuader Antennas low profile extra long whip deliver performance equal to or better than anything else on the road There s a hand wound hand tuned coil in the cup q major advance in antenna technology from the Antenna Pros field tested and field proven by thousands of CBers Only 34 98 sug
180. f the glass tip You may hear a rush of air or see a couple of white areas form near the bottom of the tube envelope To prevent glass pieces or excess solder from falling on the floor or work bench do all of the glass preparation inside of a large pasteboard box Next remove the soldering iron tip from a 150 or 250 watt soldering gun Take a six inch piece of number 14 copper wire you can remove the in sulation from a piece of number 14 romex or a single conductor electrical wire for this purpose and form a loop shaped soldering element Wrap the bare wire around the base of the tube next to the bakelite base area and in sert about one inch into the gun tip and bend over Tighten down the sol dering iron nuts real tight After cut ting a couple of glass bases you may want to snug up the soldering iron nuts for a greater transfer of heat Keep the copper loop close to the gur tips so 65 a J 2 SOLAR SWINGER pa Break off the black tube locator pin and the glass tip with some long nose pliers Z Form a loop of copper wire that fits snug around the tube and into a soldering gun Put the loop over the part of the tube you wish to cut and hold the tube firmly Wear gloves to keep from burning yourself on the hot glass Next apply heat to the loop and rotate the tube until the glass cracks the loop will heat up faster Pinch it close together and snug clear around the tube with a pa
181. f two separate two way radio systems aboard without the work has sle and cost of drilling extra holes mounting extra hardware running an ex tra coax cable and buying two anten nas Sells for 149 95 For more details on the ASM 107 and the complete A S marine products fine contact The An tenna Specialists Co 12435 Euclid Avenue Cleveland OH 44106 Organized Sound Shakespeare Marine Electronics has a deck hailjer called the Shakespeare Sound Center that is designed to co CIRCLE 81 ON READER SERVICE COUPON ordinate all functions including high power audio talking and listening from stem to stern intercom manual or automatic fog horn sounding and with optional component connections an alarm system for bilge leaks engine fires or unauthorized en try It is constructed of corrosion pro tected aluminum and transistorized elec tronic parts with a molded high impact front pane and vinyl clad aluminum cas ing The Sound C nter permits the boat s crew to project and amplify voices to hail people on board or on passing vessels docks or bridges n the listen mode it ELEMENTARY ELECTRONICS May June 1979 display stability with minimal a N on board communications can amplify conversations buoys or noises from nearby craft Selis for 199 50 Get all the details direct from Shakespeare Marine Electronics 229 N W 14th St Miami Florida 33125 20 MHz Triggered Scope The Leader
182. fferent class from the two Micro mikes just dis cussed if only because of its relatively large size This mike is 6 inches long and has a front end diameter of just under one inch This three transistor one FET mike features an omni directional elec tret condenser type microphone ele ment a penlight single cell power source a 24 flexible cord antenna at tractive black and chrome casing plus an on off switch Specifications in clude frequency range from 88 to 108 MHz radiation field intensity less than 15 uV m at 100 m maximum fre quency tolerance 75 kHz and a cur rent drain of 3mA maximum The oscillating frequency of this mi crophone is set at 90 MHz at the fac tory but you can easily tune to any other frequency in the FM band by means of a coil accessible through a small hole near the switch Battery life is put at about 100 hours With the receiver volume set at about one fourth of maximum the test noise could be heard anywhere inside the house including the basement By in creasing the radio gain excellent recep tion was obtained everywhere on the one acre lot sound quality was judged very good If the larger size is no handicap this mike should handle any domestic transmission conditions with ease FM Transmitter Kit Formula In ternational 6 95 requires the solder ing of about 17 components including ELEMENTARY ELECTRONICS May June 1979 The FM Transmitter Kit by Formula
183. g practices are vanishing as rapidly as bottles of 64 Laffite Rothschild A poor operator is known as a lid and a lid is to be pitied and hopefully educated but not tolerated If the edu catory process is approached with tact the errant operator s practices can be amended without alienating him or her In this light we bring you The Com plete Idiot s Guide to Becoming a Lid On Tuning Up Don t bother using one of those ridiculous oil filled dummy loads for tuning up your transmitter The only people who advocate their use ELEMENTARY ELECTRONICS May June 1979 by Thomas R Sundstrom w2xa are the people who manufacture them The 20 to 30 which you might waste on them could buy a lot of beer In stead find the busiest frequency on the band be it CW or phone Since most of the activity is taking place here it sor how to be a lousy Spore tory makes sense to load up your rig in the neighborhood in which you ll be oper ating right To allow for temperature variations take at leas ten minutes to accomplish tuneup throwing a test tone about every 20 seconds or so to allow for drift and to let the other ops know that you re there On Calling CQ Any frequency within your license segment is fair and legal territory for you to call CQ in You don t necessarily have to be concerned with other stations transmitting on the same frequency since you won t bother them while they are
184. ge 87 ELEMENTARY ELECTRONICS May June 1979 ik a can E bribed You get a 35 21 bribe when you try only 10 DAK ML90 high energy cassettes i only 2 19 each Hats off to Maxell Their UDXL cas sette established a new standard of quality for all cassettes The new DAK ML90 starts another new technology A technology of ex treme reliability and protection from Hi frequency losses Later we are going to offer you a valuable bribe if you will test these cas _ Settes risk free so read on YOUR TIME IS PRECIOUS Imagine yourself just finishing record ing the second side of a 90 minute cas sette and horrors the cassette jams Tape is wound around the capstan your recorder may be damaged and you ve just wasted 90 minutes of your time and perhaps lost a great recording off FM I m sure this is one experience we all dread and is one of the main reasons to buy name branded guaranteed tape you can trust Enter DAK We manufacture over one million units of cassette tape each month and many of our cassettes are us d for high speed duplication which causes more cassettes to fail than any other use When we first started DAK s cassettes failed just like many others So we in stalled over 20 000 worth of high speed duplication equipment at our factory and set out to design the perfect cassette FAILURE Faiture after failure We substituted remade tested and retested the over 2
185. gested retail Compare with K 40 at 38 50 or any other antenna You ll see there s no comparison 5 year guarantee Materials and workmanship of PERSUADER ANTENNAS Models 13505 amp 17605 are guaranteed for a full five years if this antenna is installed by the dealer and a full three years if this antenna is installed by the consumer Any part that fails within the guarantee period will be repiaced absolutely free provided the registration card has been completely filled out and returned to Antenna Incorporated A word from the Old Pro When you buy this antenna my reputation built over 38 years in the antenna business will be riding on your roof I m confident that the Persuader Antennas will persuade you you ve chosen the Best M R Friedberg President Antenna Incorporated ay In stock at your dealer now or call the Antenna Hotline 1 800 447 4700 Illinois 800 322 4400 Sorry no Hotline service in Alaska or Hawaii Charge to Visa or Master Charge and we ll have your nearest dealer ship your Persuader Antenna promptly in the mount and color of your choice Hotline orders add 1 50 for shipping and handling Applicable local taxes extra Allow 2 fo 4 weeks for delivery VINA The family of fine antennas from the fine antenna family Anienna 26301 Richmond Road Cleveland Ohio 44146 216 464 7075 In Canada Cardon Import Canada Ltd PO Box 937 Hamilton
186. gister for the ANARC 79 Convention Down the Dial Times in GMT fre quencies in kHz 610 National Broadcasting Service the voice of Trini dad and Tobago in the West Indies upped its transmitter power from 10 kilowatts to 50 kilowatts Some east coast broadcast band listeners have re ported improved reception as a result prior to sign off at 0400 4 720 The Spanish speaking station you may log here late at night has been fooling some SWLs for a long time The rea son is that it doesn t belong here at all It is a harmonic the 8th multiple to be exact of the medium wave outlet of La Voz de Cuba which operates on 590 kHz 5 055 Costa Rica in Central America is one Latin country that many SWLs are hunting for Try the outlet of Faro del Caribe which translates as the Lighthouse of the Caribbean TIFC a religious station You will find it in English prior to its 0400 sign off 9 620 Radio Yugoslavia is not the most commonly heard of the many European shortwave stations But you can hear it broadcasting in English at 2200 11 642 Looking for Radio Pakistan Try this frequency at 1815 for English programming 17 800 The Voice of Chile has been reported here at 0115 with political commen taries in English Credits Bob Fox worth NY Ernest Behr ONT Wade Smith MA Richard McVicar ONT Dean White IL National Radio Club Membership Center P O Box 118 Po quonock C
187. gned to include dual FET But more important than that mixers a monolithic crystal filter we sell it at a price you won t have ference and improve reception and a ceramic filter to reduce inter second thoughts A about By improving the transmitter circuitry the 29G L keeps you O b ree punching through loud and clear Punches through loud and clear By incorporating new features for Cema Canta mnicatipres Piedade better reception everything you 6460 W Cortland St Chicago Ilinois 60635 b k J q Write for color brochure Copy Comes ac ou arn C car EXPORTERS Empire Plainview N Y CANADA Atlas Electronics Ontari CIRCLE 6 ON READER SERVICE COUPON A _ w as j M i SEE 3 L E A J E an I P eE ra E a a Tu A a y an a u p i Passe k iP T eq r i he Fo Computer E Engineered hased Peri formance Powarwave Powerwave sil Powerwave of Base Loaded of Top Loaded of Shakespeare s Antenna Antenna Two Load Anteana NEW LONGER RANGE NEW TALKPOWER NEW STRENGTH NEW MOUNTS Black wo ocel Shakespeare s computer engineered Two Load Antenna doubles the advantage of both base and top loaded antennas Base loading means low SWR Top loacing gets the signal out With loading coils stacked and co phased in the vertical mode the Shakespeare Two Load multiplies your signal in all directions power up to g
188. greater C2 0 047 uF ceramic disc capacitor 25 volts C3 2 2 uF non polarized electrolytic capaci tor 25 voits C4 22 uF electrolytic capacitor 25 voits C5 C6 0 1 uF ceramic disc capacitor 25 volts C7 1 000 uF electrolytic capacitor 25 voits D1 1N4001 diode D2 1N4744 zener diode 15 volts Fi 0 25 amp quick acting fuse 1 1 556 dual 555 timer Q1 Z2N3398 NPN transistor or equivalent Ri R4 47 000 ohm 1 4 watt resistor R2 100 000 ohm watt resistor R3 2 200 ohm Y4 watt resistor R5 3 300 000 ohm 1 4 watt resistor R6 4 700 000 ohm 1 4 watt resistor 1 sub miniature SPST slide switch SPKR 8 ohm miniature speaker Zi touch plate requires 1 square inch of PC board stock Misc cabinet perfboard hookup wire etc ELEMENTARY ELECTRONICS May June 1979 Y LOVE AFFAIR with microcompu N ters began with Popular Electronics COSMAC Elf and progressed through the Bugbooks to the Mark 80 by E amp L Instruments Company They were great instructors but it was becoming ob vious that what I needed was a full system with a mainframe microcompu ter In choosing such a system I wanted something that was conipact and aes thetically pleasing Front panels and separate keyboards may fit the image of the electronic experimenter s labora tory but they sure clutter one s desk top I also wanted a complete system because although it puts the payments in one large lum
189. h gS Ca DAT Abo Se 2 pe s RE 7725 wa b N pra pti s j p a only 00 PERCOM DATA COMPANY INC Requires 16K RAM Dept EE 318 Barnes Gariand TX 75042 Level Il BASIC and Phone 214 272 3421 Expansion Intertace To Order Call 1 800 527 1592 RADIO SHACK and TRS 80 are trademarks of Tandy Corporation which has no relationship to PERCOM DATA COMPANY INC CIRCLE 15 ON READER SERVICE COUPON 14 HEY LOOK ME OVER Continued from page 9 Power Pumper for Car Added to the J I L Power Pumper Line of high powered car stereo units ts the Model 633 AM FM MPX Cassette unit which incorporates a special power boost switch that en ables the unit to deliver a full 20 watts RMS per channel maximum for big home stereo like sound The tuner sec tion features an FET front end and a phase lock loop cir cuit in the multiplex for top broadcast reception and excel lent FM stereo separation A Local Distance switch and FM muting are also incorporated Model 633 offers automatic reverse pusk button eject locking rewind and fast forward and tape direction indicator Adjustable shafts simplify in CIRCLE 42 ON READER SERVICE COUPON stallation It s priced at 244 95 For complete information write J 1 L Department P 737 West Artesia B lvd Compton CA 90220 S 100 Video Board SSM formerly Solid State Music has introduced the VB2 an O controlled vid
190. hat after airing the tapes the stations are expected to return them to Radio Moscow Detente Tuning In concluding Edi tor Shakov expressed his wishes for fruitful cooperation between your radio station and Radio Moscow According to United Press Interna tional at least one AM station in Illi nois WSDR in Sterling accepted the program offer If other stations across the U S fol low suit R M Will have managed to expand its program audiences to far more than SWLs AWR Expanding Many shortwave listeners are familiar with the programs of Adventist World Radio the voice of the Seventh day Adventist church Since 1950 AWR programs have been aired during purchased time by the transmit ting facilities of the Sti Lanka Broad casting Corp Sri Lanka of course is the former Ceylon the large island off the southern tip of India And since 1971 AWR programs have been broadcast under a similar arrangement by the German owned shortwave facility called Radio Trans Europe at Sines Portugal Now however Adventist World Radio is expanding its operations with its own facilities In Guatemala The project began last August and short wave medium wave and FM transmit ters were expected to be operational this year The AM FM outlets may al ready be on the air with the shortwave transmitter in Guatemala planned for international outreach to be on the air by mid year An even more ambitious AWR proj ect was
191. having a built in five band equalizer The FM de emphasis is ad justable for Dolby and non Dolby sig nal sources The FM tuner features excellent selectivity and relatively broad center tuning The signal to noise ratio mea sures 73 dB The high fidelity sensitivity on mono is 9 V 60 dB quieting while the stereo sensitivity is 80 zV 55 dB quieting Full limiting is at tained with 3 4 V At standard test level the stereo frequency response with 75 Sec de emphasis measures 0 2 1 2 dB from 20 to 15 000 Hz With 25 uSec de emphasis it is 0 3 0 5 from 20 to 20 000 Hz The AM tuner performance is about average for a receiver in this price range In the am plifier section the stereo separation is 55 dB and the magnetic input hum and noise measures 63 dB Almost everyone who has listened to the STA 2100 is impressed with the clean sound in the midrange All in all this receiver is an excellent buy for any hi fi buff at 599 95 Kenwood KD 5070 With this turn table the old adage steady as a rock is more than just a figure of speech The base is made from a composite of chunks of limestone limestone powder glass powder and polyester resin This is compression molded into marble like LR Kenwood KD 5070 x I ae k an CIRCLE 51 ON READER SERVICE COUPON material that attenuates vibrations in the turntable base The shock and vi bration resistance is considerably su Continued on pa
192. he way future computerized CB rigs are likely to go The Pace 8117 sells for 249 95 For additional information circle No 64 on the reader service coupon g FF O n OXIAa Redco RFC 50 otip aE from page 50 ample the display indicates 27 9651 with the resolution selector at the 100 setting meaning that you must multiply the reading by 100 27 9651 times 100 becomes 27 965100 or 27 9651 MHz Now suppose that yor require great er resolution Using our last example you would set the resolution to 10 meaning kHz and the reading might indicate 7 96515 You know the figure that vanished when displaced to the left was a 2 hence the frequency 27 965150 or 27 96515 MHz The er ror is again in the digits column 9 Hz maximum plus the instrument s normal error which is specified as 9 parts in 10 8 Our tests indicated reliable readings to about 46 MHz we would say the upper limit should be the specified 40 MHz The minimum input signal for a reliable reading in the RF range of 50 kHz to 40 MHz feeding the direct front panel input was nominally 30 mV somewhat more sensitive than the spe cified 100 mV Because of normal com ponent tolerances we would assume the manufacturer s claim of 100 mV to be typical The input power rating of the sam pling circuit is 100 watts P E P Our tests were limited to the maximum rating of our test transmitter which is 250 watts P E P
193. he eee ku 60 DISC CAPACITORS sest veluss long laads 437 20 TRANSISTOR ELECTRO S scot up and ax s453 u eee 1 29 75 HALF WATTERS raalatore color coded sast z 454 35 SILVER MICAS red backe sxlal asst s 455 4 PUSH BUTTON SPST PANEL N C 12 V KA 52089 v 2 sad te Whe ia ini 100 GERMANIUM DIODES axial toads u test mabe 100 STABISTORS Regulstor sensing and computer Axial ex yield 73140 100 PRINTED CIRCUIT a WATT RESISTORS sest 61060 l 42 TRANSISTOR SOCKETS asst npn and pnp types 651 x 50 3 AMP SILICON RECTIFIERS axial asst V 065 50 POLYSTYRENE CAPS plastic coatad prec s1052 E ES EES 10 NE 2 bulbe for 110vac projacts hobby ate s1222 10 PROXIMITY REED SWITCHES s 1258 6 2N915 UHF TO 18 TRANSISTORS z 1423 wa wees 30 MOLEX CONNECTORS nylon sest sizas s 5642 6 CALCULATOR AC ADAPTOR JACK standard threade 3 terminals gt 2316 50 ONE AMP ZENER DIODES aset axial u tast 71964 5 PA 263 THREE WATT PC BOARDS for empe 20131 6 MINI MOTORS 1 VOC for many hobby projects s 2551 0 1N4000 RECTIFIERS seet to BOOY y test 2594 ei 20 UPRIGHT ELECTROS erst d valuss amp capecitence gt 3226A 1 UHMF TUNER rolld state stenderd type 22927 ws 6178 A SNAP 9 VDC BAT ciip red n black lead s 2852 B 1400 VOLT RED BALL RECTIFIERS axial 1 AMP s2390
194. he swing of it so Quickly The rouble shooting Tester that comes with the Kit is really swell and finds the troubic if there is any to be found SOLID STATE Today an electronics technician or hobbylst re quires a knowledge of solid state as well as vacuum tube circuitry The Edu Kit course teashes both You will build vacuum tube 100 solid state and combination hybrid circuits Progressive Edu Kits Inc 1189 Broadway Dept 596 DJ Hewlett N Y 11557 reee OS SS q Se si Sel eee TAR oh Training Electronics Technicians Since 1946 Please rush me free literature describing the Progressive Radio TV Course with Edu Kits No Salesman will call I I ps Hewlett N Y 11557 15 The world of electronics e py YOURS FREE 32 pages of test instruments from the latest digital multimeters to the famous EICO scopes Security systems Auto motive and hobbyist products Kits and assembled EICO quality EICO value For FREE catalog check reader service card or send 75 for first class mail FICO 108 New South Road i W Hicksville N Y 11801 CIRCLE 2 ON READER SERVICE COUPON Put Professional Knowledge and q COLLEGE DEGREE in your Electronics Career through Earn Your DEGREE by correspondence while continuing your present Job No commuting to class Study at your own pace Learn
195. held CB equipment marine transceivers scanning monitors plus a Sampling of actessories are covered in a colorful 18 page brochure 312 0 1 Electronic Distributors inc carries everything from semi conductors to transformer relays to video cameras In prices ranging from 19 to 500 products appear from over 125 electronic parts manufacturers The catalog is updated 3 times a year 313 Get all the facts on Progressive Edu Kits Home Radio Course Build 20 radios and electronic cir cuits parts tools and instructions included 314 Cover the Ham bands from 80 to 10 meters with one classy rig Swan Electronics 100 W 100 MX mobile transceiver Get the details direct from Swan 316 Get the Hustler brochure illustrating their com plete line of CB and monitor radio antennas 318 GC Electronics offers an Electronic Chemical Handbook tor engineers and technicians It is a problem solver with detailed descriptions uses and applications of 160 chemicals compiled for electronic production and packaging They are used for all types of electronic equipment 320 Edmund Scientitic s new catalog contains over 4500 products that embrace many sciences and fields 321 Cornell Electronics Imperial Thrift Tag Sale Catalog features TV and radio tubes You can also find almost anything in electronics 327 Avanti s new brochure compares the quality difference between an Avanti Racer 27 base loaded m
196. higher densities than can be achieved with other storage technologies known today In the photograph inventors from left Dietrich Haarer George Castro and Roger Macfarlane are shown adjusting an appa ratus that projects the light from a laser onto a sample of a photoreactive material Work on the new storage technique is still at a very early stage of research We have a long way to go before this can be made into a technology says Dr George Castro manager of the IBM San Jose laboratory s physical sci ence department So far we are in vestigating a variety of potential storage materials and trying to understand the temperature limitations of the phe nomena We still have to address the many unsolved problems that have pre vented other optical methods of stor age from becoming technologies In fact optical methods of storing infor mation were expected to lose an im portant advantage namely that of high storage density as the storage densities in the existing magnetic recording tech nologies approach optical limits in the next decade Hole burning breathes new life into optical storage by theoretically extending that density a few orders of magnitude ELEMENTARY ELECTRONICS May June 1979 iv X ea a lt x 0 0005 Speed Accuracy Don t buy any turntable before you see the new direct drive Rea istic LAB 500 It s already switched many an audiophile to Radio Shack s 2
197. his man his patents his improvements his methods of scientific inquiry and his formulation of modern day research The list of corporations reads like an electronics industry Who s Who and includes such household names as American Telephone and Telegraph Allis Chalmers General Electric GTE Sylvania RCA Westinghouse Electric many well known electric power com ELEMENTARY ELECTRONICS MasJune 1979 mam Edison s 1889 Strip Kinetograph the first motion picture camera using strip film Note that the film moved hori zontally 20 40 fps panies and even the Japan Atomic Energy Commission Is it possible for a man or woman having Edison like inventive genius to make his or her mark these days as an independent thinker arid doer Or does the pace and sophistication equate that with high cost of modern research demand that scientific brains congre gate in corporate laboratories or find refuge in university laboratories there to plead for research grants year in and year out Is it possible to be a truly free inventor and still survive In short would a latter day Edison be an anachronism in modern society The issues could be debated endless ly and this is not the place to start I might make this one personal obser vation Many years ago when I left a plush chemical research laboratory rife with intra company politics to work in a far more primitive labora tory in a smaller compan
198. i sm UU l l S 7 s a U OST COMPUTERS CAN BE MANAGED quite nicely by learning one or more of the popular high level lan guages like BASIC or PASCAL That does not however prevent us from be ing a trifle curious about what is really going on inside the machine One can drive a car quite well without any idea of how the engine actually works and one cannot repair a car without de voting more attention and study to its functioning than most of us can afford Many people however get a degree of Satisfaction from appreciating the basic concepts of how it works The same can be said of computers and the people who use them It is a well known fact that a digital computer consists of an input output device central processor and memory and that it does all its work by manipu lating Fs and 0 s which are represented by pn or off conditions of electronic switches But how is all this activity Organized and how does the machine accomplish all its complex computations at such rapid speed using o ly on and off states Communication To answer this ques dion we must take a quick look at how the central processing unit or CPU communicates with computer memory and then a more detailed look at what goes on inside the CPU The simplest way to think of the CPU is as a mail man who goes from one numbered mailbox to another in succession The mailboxes are locations in computer mentory which contain program in Struc
199. ica tions Frequencv Counter is priced at 179 95 complete with AC and DC power cords For additional informa tion circle number 68 on reader ser vice coupon ia ELEMENTARY ELECTRONICS May June 1979 YOU RE UNDER SURVEILLANCE A HOST OF PEOPLE AGENCIES AND COMPUTERS ARE BUSY SPYING ON YOU AND YOUR BUSINESS EVERY DAY OFTEN ILLEGALLY HOW TO STOP IT OR DO IT BACK THE BIG BROTH GAM A Large Format 8 4 x 11 Quality Paperback 240 Pages BUGGING WIRETAPPING 11 TAILING OPTICAL AND ELECTRONIC SURVEILLANCE SURREPTITIOUS ENTRY DETECTIVE TECHNIQUES WEAPONS COUNTERMEASURES A VIRTUAL ENCYCLOPEDIA ON SURVEILLANCE EVERYTHING YOU VE ALWAYS WANTED TO KNOW ABOUT SPYING PLAYBOY MAGAZINE With Each Order You Receive Free Other Material And Literature For Investigative Procedure l QUIMTRONIX Postpaid P O Box 548 EE Seattle Washington 98111 CIRCLE 17 ON READER SERVICE COUPON DEVICES u PHASERS PPF 1 PHASER PAIN FIELD This device recently deve Oped and patented in our labs is being evaluated by law enforce ment agencies for riot and crowd control It is now available but soon will come under the jurisdiction of weapons and internal machine control making it unavailable to the public The device is hand held and looks like a BUCK ROGERS ray gun It s hazar dous if not used with discretion PPF 1 PLANS 15 00
200. icroelectronics 266 p 228 11 708 Modern Applications of Linear IC s 276 p 301 513 Understanding Solid State Circuits 192 p 104 l 116 Getting Started with Transistors 160 p 90 495 6 95 59 95 5 95 6 95 4 95 795 5 95 6 95 5 95 5 95 9 95 4 95 3 95 ENGINEERING amp REFERENCE 1035 Instrumentatior amp Control Sys Eng Hdbk 434 p 184 i 1995 929 Solio State Motor Controls 322 p 162 742 Prot Electrical Electr Engrs License Study Guide 476 p 750 Etectronic Conversions Symbots amp Formulas 224 p 46 il 829 impedance 196 p 90 Il 774 Digital Logic Elactronics Handbook 308 p 226 I 118 Etectronics Data Handbook 256 p 149 l 101 Electronic Circuit Design Hdbk 4th Edition 416 p 966 l 125 Handbook o E ectronic Tables 224 p 161i MODEL RADIO CONTROL 1135 Radio Control Nanual Sys Circuits Const 3rdE3 256 p 5 95 a r Mode Arpianes Helicopters by AC 192 p 140 l 4 95 747 RC Modeler s Handbook ol Giiders amp Sailplanes 196 p 90 il 4 95 812 Radio Control tor Models 350 p 417 l 6 95 693 Modei Sail amp Power Boating by Remote Control 192 p 125 4 4 95 122 Advanced Rado Control 192 p 181 11 4 95 74 Modei Radio Control 192 p 192 l BROADCAST CATV CCTV amp VIDEOTAPE 865 CATY Program Ongination amp Production 256 p 64 II 811 Compiete Hdbx of Videocassette Recorders 280 p 160 852 B cast Engr amp Maintenance Hdbk 532 p 235 l 8
201. icrophone three transistors a tuning capacitor choke coil modulation transformer and sev eral capacitors and resistors all of which are clearly identified The manufacturer claims broadcast range can be as much as 40 feet under ideal conditions The author managed transmission over a somewhat shorter range indoors There is no critical coil tuning required Just set your AM to any unused frequency and rotate the tuning knob on the components board to match the frequency Because of the limited range and especially because of the bulk of this wireless the Broadcaster cannot be put into the same class for comparison with the FM mikes already discussed It s not intended to be a working mike but a Science Fair educational kit As such it meets all claims made for it a Manufacturers of Wireless Microphones A M C Sales Inc Box 928 Downey CA 90241 Formula International Inc 12603 Crenshaw Blvd Hawthorne CA 90250 MLI Industries 50 Hunt Street Watertown MA 02172 Radio Shack 500 One Tandy Center Fort Worth TX 76102 Buy from local stores Ramsey Electronics P O Box 4072 Rochester NY 14610 45 N AMPLIFIER STAGE that is used at two widely separated frequen cies such as RF and audio is called a reflex amplifier This type of amplifier circuit was used in the early days of radio because of its economical use of the then expensive vacuum tubes Later during the depre
202. in a few sp nic s I tools or electro KAG SAVE 15 ON ALL PAC Convert Can be bu No specia LIFESCREEN IH The LIFESCREEN Ili projection system gives you all the enjoyment and excitement of the 4900 systems Our new injection moided Tron Ex lens F 1 9 produces an amazing image that is over 3 times brighter than most nationally marketed big screen T s including Sony And the Tron Ex delivers sharper tocus to the screen edge for better overall clarity Our light enhancing Extron LS 50 screen Is 6 times brighter than most movie screens because the molded parabolic contour rejects extraneous light concentrating a directionally selective TV image for clear colorful viewing The LIFESCREEN Ill plans provide exact dimensions to fit the 13 Toshiba model C389 but they can be modified to fit most 12 to 19 portabies Pre constructed LIFESCREEN ill lens housings availabie for most TVs Order the components cataiog below COMPLETE PACKAGE 319 LIFESCREEN Ii LIFESCREEN The self contained projection system The original independent projection that uses any transistor portable TV system from Extron Works with the 12 to 19 requires Only 2x 4 Sharp 13 modei 13429 color TV or teet of floor space tits neatly against Sony 15 model KV1541R color TV any wall and lends its beauty to the decor Can be used with any size screen The of any room Includes Tron Ex F 1 9 LIFESCREEN includes our new Tron Ex lens Extron LS 50 screen
203. ing into other people s affairs for monetary gain Such activities do go on yet the fact remains that there are virtually endless applications for wire less microphones that are entirely legal and unquestionably ethical Regular readers of ELEMENTARY ELECTRONICS of course need not be re minded that there are proper and im proper uses for just about anything from dynamite to every conceivable va riety of electronic gear But just in case a reader loses his copy of EE and it falls into the wrong hands we hasten to append this warning FCC rules clearly prohibit the use of wireless microphones for eavesdropping on the conversation of unsuspecting people Getting caught at wireless snooping could lead to fed eral prosecution Moreover the citizen whose privacy has been violated is very likely to file a king sized civil suit for damages Using the Mike A wireless mike FACE IT Wireless microphones a gt g n Microphones have come a long way Compared to this Prohibition era monster AMC s Micro Mini Mike is truly microscopic Its transmitter operates on FM in the 88 to 108 MHz band It sells for 18 95 including battery Circle 73 on Reader Service Coupon system can be a very handy electronic watchdog You can hear the baby cry respond to a call from a bed ridden patient or run for the telephone or door when either bell rings Just plant your mike in the appropriate location and take your portable b
204. ips TMC 4907 a 4 mhz crystal a Mostek MK2002 plugs into a wire wrap board of 120 sockets Also 2 large heat sinks 4 2N3055 xistors 2 2N3668 4 jumper cables with dip plugs attached 30 lamps No 382 amp other stuff Power required for keyboard 5VDC to 12VDC regulated Pin out supplied for keyboard only Keyboard in console is acomplete assembly ASC11 encoded amp is easily removed to fit or use as is The additional circuitry was used to drive status indicators Format program level check amp display etc Console size 19 wd x 16 dp x8 hg rear front slopes to 2 3 4 hg Removed from equipment Good to excellent condition Sh Wt 16 Lbs 8WO0584 for 188 88 8W0584 BURGLAR ALARM BOARD Neat new closed circuit alarm board will latch a relay if the alarm circuit ts opened This unit operates on 12 VDC at such a low price it makes a perfect compact alarm component With Data Oty Ltd Sh Wt 6 oz 8K30267 2 88 5 for 13 88 8K30267 13 88 5 74100903 001 68 88 SPECIAL OFFER POWER SUPPLY KIT INPUT 115V 60 117 We supply all electrical amp electronic parts you supply labor amp mechanical parts tools amp case Battery Charger 12VDC 20A 20 Lbs 7C70005 20A i 19 50 Battery Charger 12VDC 15A 15 Lbs 9c0089 15A 14 50 Ni Cad Battery Charger Kit Up to 35 VDC 50 Ma Sh Wt 5 Lbs 7
205. ir of long nose pliers You have now constructed a copper wire loop to replace the soldering iron tip Slip the wire loop over the end of the tube base and press the loop to gether at the ends but not so close as 66 f a Note the clean easy cuts this technique pro duces Make sure you have a back up tube The four copper support wires are soldered into the pin bases The components are soldered and glued to these supports to touch Now hold the tube in the left hand and soldering gun in the right Very slowly turn the vacuum tube in side the heated loop Within a few min utes you will hear the glass crack and break in a perfect cut at the base of the tube Some glass tubes take longer to break than others In the meantime you may smell a hot bakelite odor from the wire loop which is normal Often the glass will crack clear around and just a tap on the end of the bakelite base separates the two pieces If you have selected a tube with a metal cap on top turn the inside com ponents until the connecting wire breaks off Be careful not to break the remaining glass envelope which is very brittle It s best to cut off the wires con necting the tube elements to the base with a small pair of side cutters In case the tube elements and mica in sulators will not pull through the small opening use a pocket knife to cut out sections of the insulators You may have to crush or remove the tube ele ments in se
206. is it is not com plete there is no base current flowing A Caig i QUESTIONS 40 How much collector ahi is flowing 41 What is the collector voltage ee ees ee 42 What is the voltage at the point Vc in the mechanical switch cirevit l WR oe pees ANSWERS 40 None 41 Since there is no current flowing through the 1 ko resistor there is no voltage drop across it So the collector will be at 10 V 42 10 V since there is no current flowing through the 1 kO resistor From the preceding section it is obvious that a tran sistor with no collector current can be considered simi lar to an open mechanical switch For this reason a transistor with no collector current and its collector voltage level at the supply voltage level is said to be turned off or just OFF Now work through this ex ample and compare the re sults to the examples above Again the object here is to find Vc k w 8 k oses 8 8 8 8 8 8 ooo ooo ool l olp y dy G ol eee 2 8 G 8 u 0 s G s 5 E es 8 E eh E E E E E E E lll E E 8 8 8 8 8 8 8 s 8 8 we 8 8 eB ee lle E n 8 8 2 8 8 8 8 s ee s s s s E ANSWERS 71s m IC 50 x 0 1mA 5mA 4 j 44 Vr 1k0 x5mA 5V 45 Vc 10V 5V 5V Note the output
207. ity SS Total State Zip Code C Check J Money Order O Master Charge O Visa BankAmericard Exp Date Account No Interbank No Master Charge only MO53 i x MAIL TO l Q Indianapolis IN 46206 Signature Howard W Sams amp Co Inc Prices subject to change 6 months after issue date Minimum credit card purchase 10 00 4300 W 62nd St Bh OE EE a ie vad See The Newest In Quality Electronics You A Super Accurate Digital Alarm The ideal choice for a first kit with snooze fea ture AM and PM indicator 12 or 24 hr format and pleas ant green biue digital dis play Budget priced too A Doorbell That Plays Your Favorite Tune A fun way to greet guests with any 16 note tune you pro gram and you can even add remote speakers Custom Car Accessories like the Heathkit GC 1406 Digital Quartz Car Clock shown or it s companion car clock with trip timer and stopwatch functions for the rally enthusiast are easy and fun to build And you have the quality and dependability in custom car accessories you can show off with pride Now you can choose one of these fine car clocks a windshield wiper delay a deluxe mobile siren and P A system an ultra sonic intrusion alarm an electronic speed control or a cab to camper intercomm all in money saving kit form you can q build service and install yourself Low Cost Home Security with this Heathkit GD
208. ivers Pullin Signals Be Cathode Ray Tubes Explained How Capacitors Work Using Magnetism SROGQMPUTER in Electronics And more TS Mahe i w tet mi usk puge 29 Mach rate ithu h mit WATE r page gt b1 Count hiku acumpeter pog suysrors AN be Shon jane Super ENJOY GREAT ARTICLES CR s uno Happmess LIKE THESE e checks out cui 250 programm p acorn Indy Cator y quit tachometer pr matin pol td k nde hpr va e How to Build Your Own Transformer How to Select the Right Shortwave Receiver e The Burgeoning World of Micro computers e Quickdraw Rickshaw The Electric Car that Really Gets Around What s Really Wrong with FM Radio How to Power Up Your Antique Radio e The Vanishing Vacuum Tube e How to Customize Your CB Antenna e Those Incredible TV Sets of the Future e Listening in on the Forgotten Continent e DXing Endangered Species e Sandbagging CB Fun Without a License e The World s Worst Hi Fi Com ponents gt EXCITING DISCOVERIES What ever your particular interest in elec tronics you ll be entering a world of discovery in the pages of ELEMENTARY ELECTRONICS ELEMENTARY ELECTRONICS is regularly 6 95 for 6 issues one year TRY A FEW ISSUES AND EVALUATE OUR But with this special introductory offer you can enjoy a full year for only 3 98 gt HOW TO DO IT HELP Tips and ORDER pointers that add up to money saved TODAY
209. ized An unbelievable advancement for punch in programming It searches in no crystai scanning ab stores and recalls every bit of programming on a vast 50 channel spectrum Automatically Unbelievable Read and believe CRYSTAL LESS Micro processor controlled Brings in every local frequency automatically without a crystal 50 CHANNELS Scans up to 50 channels in banks of 10 each Scans any combination of banks at the touch of a button SEARCH STORE Seeks put and stores up to 64 active local public service frequencies automatically SEARCH RECALL Retrieves stored frequencies for simple entry into scan program PRIORITY CHANNEL Samples a designated priority frequency on channet 1 every two seconds DIGITAL CLOCK A genuine LED quartz crystal digital clock Shows hours minutes seconds THE INCREDIBLE NEW ear COVERAGE Lew high AND HF UHF T Plus 2 meter amateur ham st a censor oN BEARCAT 250 SCANNER COUNT Transmissions on each ei gk ed Id Delay ant amp e frequency counted automatically to determlne which are most active eq dk tele LEADING THE WAY TO REAL EXCITEMENT SCAN SEARCH LOCKOUT A Track Tuning Circuitry Front unique feature Not only locks out Mounted Speaker Decimal channels while scanning it also eliminates Display Quality Construction unwanted frequencies while searching AC DC UL listed FCC Certified Copyright 978 Masco Corporation of i
210. key 256 p 36 845 How to Prepare a Production Budget Film amp Videotape 541 Videotape Prod amp Comm Techniques 256 p 100 3 793 TV Lighting Handbook 228 p 230 11 COLOR TV SCHEMATIC SERVICING MANLALS Each vo has compete service data pans lists tuli size SChemalic fold out section and all Olher into needed Each 8 12 x 11 less Oih rwise mareed 662 Sveing New Modular Color TV Recvrs Vol 1 178 p 545 Admiral Vol 1 196 p 12 schematics 641 Admral Vol 2 196 p 11 schematics 741 Arline Montgomery Ward 196 p 12 schematics 536 General Elecrtric Vol 1 196 p 12 schematics 609 General Elecinc Voi 2 212 p 10 schematics 879 General Elecinc Vol 3 196 p 560 Jap Vol 1 Sony Sharp Midiand 212 p 576 Jap Vo 2 Delmonico Hilach Panasonic etc 212 p 684 Japanese Vci 3 Hilachi Sanyo Coronado 228 p 692 Japanese Vai 4 Sharp Midland MGA 236 p 36 p t o 700 Japanese Vc 5 Sony 196 p 36 p toidout 526 Magnavox Vol 1196 p 12 schematics 589 Magnavox Vo 2 196 p 9 schematics 770 Magnavox Vol 3196 p 36 p schemalic foldout 509 Motorola Vol 1 178 p 6 schematics 584 Motorola Vol 2 196 p 9 schematics 522 Philco 196 p 12 schematics 496 RCA Vol 12 p 12 schematics 578 ACA Vol 12 p 12 schemaiics 720 RCA Voi 96 p 12 schematics 721 ACA Vol 96 p 12 schematics 822 ACA Vol 96 p 36 p schematic section 6 95 5 95 6 95 5 95 8 95 5 95 5 95 5 95 4 95 4 95 5 95 85 95 7
211. l controls for channel selection volume squelch RF gain and Delta tune Switches for PA CB Noise blanker ANL chan nel indicator dimmer and tone Standard accessories include a micro CIRCLE 53 ON READER SERVICE COUPON phone mobile mount DC power cable Receiver Section Test Input sensitivity 04a Adjacent channel rejection 56 dB AGE et in a ae 1 dB Input level for S9 meter indication 40 V Transmitter Section Test AM RF output 3 8 watts Modulation to 85 yes 76 j Relative sensitivity for 85 MORA aa la an 43 dB Modulation limited to 100 yes Editorial Remarks The Mark V has a 6 dB per unit S meter double con version jacks for P A and remote speakers L E D digital channel indi cator S RF output meter E e GENERAL ELECTRIC 3 5875 469 95 General Electric General Description A 40 chann l AM SSB transceiver or mobile P A base operation Fine tuning 2 2 kHz is provided Power supply CIRCLE 62 ON READER SERVICE COUPON is 12 to 13 8 VDC with negative or positive ground and 120 VAC There are front panel controls for channel selection volume squelch Fine and coarse clarifier tone MIC power RF gain SWR CAL and L E D dim Switches for power AM SSB modes ANL noise blanker CB PA MOD SWR_ meter antenna A B speech compressor and clock timer set Standard accessories in clude a microphone mobile mount DC power cab
212. lder down inside the base next to the support wires Place a 6 32 inch machine screw and washer in the center hole of the tube socket Slip a nut on the outside of the screw to hold it in position until the socket can be bolted to the wooden base Temporarily slip the glass en velope over the support wires to see if they will clear the top area You may use longer support wires if the glass envelope is a lot longer in length This may help string out the parts and keep them from shorting against each other A cut glass envelope from a SU4GT tube runs about three inches long A tubes pin terminal connections bottom view are shown Remember the tie wire supports are reversed when the tube socket is upright Scratch a line straight up from the tube locator pin along the side of the socket with a pocket knife Now place a piece of masking tape around it and mark the support wires You can now solder to your heart s desire The four supports will be used for component tie points and they are marked upon the sche The photo cells are mounted on two sides of the frame The loop stick fits neatly in the middle of all the components The transistors are in the base of the tube matic Wire support number 8 is used only as a wiring tie point for the small components All other support term inals will be tied into the circutt after the tube socket is bolted to the wooden a SR o ET BOTTOM amama a
213. le and A C power cord Receiver Section Test Input sensitivity 0 4 aV Adjacent channel rejection 57 dB AGG action oat oe 9 dB SSB opposite sideband rejection 2 08 A 90 dB Input level for S9 meter indication Transmitter Section Test AM RF output 3 5 watts SSB RF output 11 5 watts P E P Modulation to 85 oo yes Relative sensitivity for 85 mod 30 to 45 dB ua ha limited to 100 yes Editorial Remarks The 3 5875 has a relative reading S meter double conversion jacks for P A and re mote speakers L E D digital channel indicator speech compres sor Modulation SWR and S RF output meters and connections and switching for two antennas Has dig ital clock timer l B e MOTOROLA CB555 409 95 Motorola Inc General Description A 40 channel AM SSB transceiver for mobile P A _ base operation Fine tuning 1 1 kHz is provided Power supply is 12 to 13 8 VDC with negative ground and 120 VAC Features L E D digital clock that works on AC only Overall dimensions are 4 7 16 in H x 11 in W x 1ll in D There are front panel controls for channel selection volume squelch RF gain clarifier mike gain SWR cal Switches for CIRCLE 66 ON READER SERVICE COUPON AM LSB USB S RF SWR meter mode PA CB Extend Extend is a Noise Blanker ON OFF AUTO for Continued from page 94 ELEMENTARY ELECTRONICS May June 1979 a a a mak
214. le on first order McCord s 2932 Cassell Dr Anderson IN 46012 AMAZING Mailorder Profits Using Proven Meth ods Free Details Rasmussen DP59 1747N 450E Ogden Utah 84404 BIG Profits Selling Books by Mail Turnbull D1 B 6701 Burbank CA 91510 50 000 ANNUALLY Free Gift and Details Taylor Box 20008D Columbus OH 43220 BUY IT WHOLESALE 400 000 BARGAINS Below Wholesale Many Free Liquidations Closeouts Job Lots Single Samples Free Details Worldwide Bargain hunters Box 730 IO Holland MI 49423 PLANE rides for gas Towels 191 2 etc Booklet Bargains By Mail offers fantastic buys 3 00 Guaranteed Saltz 2370E 16Q Brooklyn 11229 DO IT YOURSELF REPAIR TV S ANYONE CAN Easy Guaranteed Free Details Publication Box 517X Brea CA 92621 For Greater Classified Savings Results and Profits Portable Free Details Bumper EPB 22791N Combo DO IT YOURSELF Cont d FREE Encyclopedia Winemaking Beermaking Sup plies Equipment Ingredients Vynox Industries Box E E 7498 Rochester NY 14615 BUILD Stereo Speaker Cabinets microphone mixer mebile amplifier 12 volt convertor Specify plans desired One dollar each self addressed stamped envelope SC Enterprises Box 1059 Hamilton OH 45012 BUILD your own car stereo power booster 1 00 for plans or sase for details Perkins Company Box 680 Rainier Oregon 97048 EDUCAT
215. lecting hobby Everyone hav ing such a book would know what his radios were worth as well as what other collectors radios that he might consider buying are worth The An tique Wireless Association has made a small beginning by listing prices for radios that have been sold or auctioned at their meetings To my knowledge there is only one appraiser for old radios now active There are discussions going on at this time with the thought of establishing a nation wide Antique Radio Apprais ers Association Well qualified collec tors living in various parts of the United States would become members of the staff This way any collector desiring an appraisal could find an ap praiser within a few hundred miles Any reader who would like to com ment on the tnsurance and appraisal discussion is welcome to write to me in care of ELEMENTARY ELECTRONICS magazine ELEMENTARY ELECTRONICS May June 1979 Features BRAND NEW JUST RELEASED 1979 IC MASTER 2500 pages Complete integrated circuit data selector Master guide to the latest C s including microprocessors and consumer circuits Texas Instruments Low Profile Sockets world s LINEAR I C S LM324N 49 LM339N 49 LM555N 8 29 LM556N 14 59 LM723CN 34 LM723CH 39 LM741CH 37 LM741CN 8 24 LM1458N 8 39 Quad Op Amp Quad Comparato Timer Dual Timer Voltage Regulator Voltage Regulator Op Amp Op Amp Dual Op Amp VOLTAG
216. lters with center frequencies of 5 kHz 9 kHz and 13 kHz The AD 1304 continuously moni tors the program for high frequency content in the range of each filter When there is no program content the filter is normally in circuit and the higher frequencies are attenuated starting at about 2 kHz Since continu ous noise hiss are high frequencies it is attenuated by the bandpass filters If there is high frequency program information within the range of a filter it iS sensed and the filter is shorted al 59 2 J AUDIO PROCESSOR lowing the frequencies within the range of that particular bandpass filter to pass through to the output unfiltered Each filter continuously samples the signal opening and closing in step with the program information This is dy namic high frequency filtering in con trast to a fixed high frequency filter that attenuates high frequencies re gardless of the program signal s fre quency distribution Figure 2 illustrates the dynamic noise filter The more or less flat line is the overall response to high level signals in the range of 20 to 20 000 Hz The roll off which starts at about 1 5 kHz is the maximum filtering of high fre quencies obtained when there is no high frequency program information to short the bandpass filters You can actually see the nulls of the center fre quencies at 5k 9k and 13kHz Fixed Filter For those really tough noise problems sych as an old wor
217. m Savings Choose from Heath s complete line of quality audio products for the kind of custom sound reproduction you want from the newest and finest professional rack mounted components to a full range of super value com ponents Including receivers tuners amplifiers pre amps custom control systems speakers and name brand turntables and cartridges ali available individually at low catalog prices or at money saving system discounts Radlo Control Gear You Can Depend On From the leader in R C development See this new 8 chan nel open gimbal transmitter with Heath s instant plug in frequency change feature all Heath firsts ptus sensa tional savings on complete systems and R C Starter Sets Choose from the nearly 400 quality Heathkit products for home or business including the world s finest values in amateur radio equipment complete personal cornputing systems and educational programs Every Heathkit product is backed by world famous technical service and counsel plus sales and service facilities for 54 Heathkit Electronic Centers coast to coast units of Schlumberger Products Corporation See the white pages of your phone directory 20 ELEMENTARY ELECTRONICS May June 1979 HEATHKIT CATALOG See and read about the most exciting electronic products around all in easy to build money saving kit form from Heath world leader in kit electro
218. maximum sensitivity in the clockwise position The second modification requires that the l uF disc capacitor in the upper left hand corner of the S 210U be unsoldered In the holes vacated by the capacitor install and solder a jump er of bare solid hookup wire The third step is to cut the red wire 35 1S m 2 THE THIRD EAR in the lower lefthand corner completely off at the point where it joins the PC board Finally unsolder the 32 uF elec trolytic capacitor from the board and replace it with a similar unit having a higher working voltage 16 VDC or higher In general your replacement may have a value anywhere between 22 and 47 uF with 33 uF being about optimum Remember that since you are dealing with electrolytic devices the orientation must be correct In the pic torial you can see that capacitor posi tive must be pointing upward Now lets see how the modified S 210U mates with the rest of the cir cuitry in our Third Ear As the sche matic diagram shows the green and black leads of the module are its only connections to the external circuitry Capacitor C2 bypasses the module s supply leads in order to keep the sen sitivity high while R1 isolates C2 to reduce its effects on the performance of the rest of the circuit Whenever the module s SCR latches into conduc tion due to sonic triggering current will be drawn through relay K1 and the LED1 R2 combination As a re sult the
219. mmunicator either ham SWL scanner buff or CBer you ll want a copy of Harrison Radio s Communications Catalog 1979 Just what the shack book shelf needs 372 Just what the experimenter needs can be found in Olson s bargain flyer parts assemblies semiconductors Components and more Even more interesting are the prices 379 There s everything in the area of musical synthesizers for drums Strings other instruments and full orchestras as well as audio gear video display modules and a computer in PAIA Eiec tronics catalog 380 If your projects call for transistors and FETS linear and digital ICs or special solid state parts then look into Adva Electronics mini catalog for rock bottom prices 384 The B amp K Precision test instruments are de scribed in a new compact catalog all experimenters shou d have Start stepping up your test bench capabilities t 301 Get into the swing of microcomputer and microprocessor technology with CRE s new Pro gram 680 New 56 page catalog describes all pro grams of electronics advancement 302 Big catalogs are coming back 8urstein Apple bee will send you theirs It s a parts bonanza every experimenter would want to see Latest Catalog is over 200 pages 303 Graymark s catalog reveals a host of products and kits every experimenter would like to have Unusual binary clock is a winner A must Catalog for the beginner 305 A new 4 page directional beam CB a
220. mounting tabs you may have to make some holes potential of the green lead drops to less than one volt which is less than the 2 volt minimum needed to turn on the D2 D3 Q2 combination Conse quently Q2 s collector no longer con ducts current and the potential across capacitor C3 rises as charging occurs through R5 and R6 The rate of ascent is controlled by potentiometer R5 higher resistance causes the potential on C3 to climb more Eventually the voltage on C3 will reach a critical level at which point unijunction transistor Q3 s emitter to base 1 impedance will break down to a very low level This rapidly discharges C3 and causes the appearance of a voltage spike across resistor R8 This voltage spike drives current through R4 into the base of transistor Q1 As a result Q1 s collector conducts current heavily thus shorting the mod ule s green and black leads together REMOVE THE ORIGINAL 5K TRIMMER AND INSTALL IN ITS MOUNTING HOLES THE WIRES FROM a2 SkK POT REMOVE OluF pisc gap 8804 RESISTOR ACITOR AND INSTALL A WIRE JUMPER IN ITS PLACE x XTAL MIC RED WIRE This deprives the SCR of anode cur rent causing it to unlatch Because the voltage spike lasts only a brief instant less than 0 1 second Q1 soon loses base drive and ceases to conduct When this happens current can no longer activate K1 or LED1 and both will remain off until another sound triggers the module As you can see
221. mped envelope Freedom 02 11 Box 1060 Orange Park FL 32073 _ PEN PALS JOIN North America s leading penpal club Details Irom Friends Worldwide CP 95 F Anjou Montreal 1 4G5 PERSONAL BEAUTIFUL GIRLS from all continents want cor friendship marriage Sample photos free Hermes Verlag Box 110660 D 1000 Berlin 11 Germany SINGLE Widowed Divorced Nationwide intro ductions Identity Box 315 DC Royal Oak MI 48068 STOP forgetting important dates For complete in formation send 1 00 Refundable to KAZ Enter prises P O Box 19563 Indianapolis IN 46219 NEW Luxury Car Without Cost Free Detalls Codex CC Box 6073 Toledo OH 43614 To be included in the next issue pelase send ord r and remittance to R S Wayner ELEMENTARY ELECTRONICS 380 Lexington Ave New York N Y 10017 I PERSONAL Cont d DATES GALORE Meet singles anywhere Cali DATELINE toll free 800 451 3245 RECORD Telephone conversations privately auto matically Leave recorder Unattended Robert s 2618 Elmwood Blvd Wausau WI 54401 JAPANESE Girls Make Wonderful Wives We have large number of listings Many interested in mar riage Only 1 00 brings application photos names descriptions questionaire Etc Japan International Box 156 AA Carnelian Bay CA 95711 BEAUTIFUL Mexican Oriental girls Needing Amer ican Boy Friends Free Details actual photos World Box 3876 D
222. mple be first con verted to 3100 kHz Thus a Station s image would be a full 6200 kHz below its real frequency If you can t afford a dual Conveision receiver at least one that doesn t over load try for some amplification before the IF Even one stage of amplification at the original frequency will reduce image problems Two stages are even better but more expensive than a qual ity synthesized frequency receiver W 87 HOW TO ORDER MORE OF WHAT YOU RE READING INCOME OPPORTUNITES MAGAZINE lt the greatest gold mine of money making ideas In any one place Special Offer for Opportunity Prospectors Big Monthly Issues for Only 2 98 H9DO14 Zip 1 35 YOU PAY ONLY 33 cents State Regularly 1 00 a copy on the newsstand Directory issues Please bill me only 2 98 for 9 issues of INCOME OPPORTUNITIES Enclosed is 2 98 check money order INCOME OPPORTUNITIES for 9 issues P O Box 2610 Greenwich Conn 06835 ame Address City 88 _ Kathi s CB Carousel Continued from page 75 at any time On the other hand if you re just looking for action you could simply have the computer continuously scan all 40 channels searching for a busy or unused channel Since the computer also tunes the transmitter to the received channel though it will not scan in the transmit mode protection is provided against an invalid entry Should you try to enter a
223. n ter of a 360 compass which is also centered on the cabinet s top The second part of the system is a somewhat oversize loop antenna as sembly that plugs into the loop ampli fier The loop can be continuously rota ted through 360 or tilted 90 from horizontal A tilt scale is part of the loop assembly The rotational scale is the 360 compass on top of the loop amplifier The loop itself is but a small part of the total loop assembly but the oversize hardware permits the loop to be positioned by the user without hand effects on the loop antenna it self 55 PALOMAR LOOP When the antenna is plugged into the loop amplifier the tuning capacitor which is built into the amplifier tunes the coil to the desired frequency or narrow range of frequencies there by providing the amplification asso ciated with high Q tuned circuits Though the amplifier itself is rated by Palomar for a nominal gain of 20 dB we attained signal improvements of 3 to 6 S units which represents a gain range of 18 to 36 dB assuming the accepted value of 6 dB per S unit The extra 16 dB of gain 63 dB 20 dB ts actually the result of tun ing the loop and the gain is realized in comparison with reception from a re ceiver having a built in BCB antenna Peak or Null For some unaccount able reason Palomar stresses using the device for nulling a strong signal in order to reduce interference to a
224. n 78 rpm record the AD 1304 provides the fixed high frequency filter shown in Fig 3 The straight line is the overall response with the filter switched out Switched in the filter is 3 dB down at about 7kHz and 10 dB down at about ISkHz This is what s known as a mild filter meaning it can be used with most program sources even mod ern recordings and will not remove so much high frequency program informa tion if recorded that the signal gets an overall muddy sound quality Adjust To Taste Both the expander and dynamic filter have front panel sensitivity adjustments that allow th user to establish the optimum value of expansion and naise suppression for a particular system or recording Screw driver adjustments on the rear apron for both the left and right inputs al low the user to match the sensitivity to the normal program line level EXPANDER MODULE 3 9 AND 13 kHZ FILTERS The expander and three filter modules plug into the main board assembly The test meter is built into the cabinet and is used for circuit alignment during construction and for circuit testing 60 Once connected to the associated amplifier each function can be indi vidually switched in and out or the tape monitor can be switched in as the signal source for the processor With all processing switched out the overall fre quency response is 0 2 dB 20 20kHz at a distortion no higher than 0 1 THD Build It Yourself The
225. ndiana CIRCLE 30 ON READER SERVICE COUPON ELEMENTARY ELECTRONICS May June 1979 25 Portable Miniscopes for Electronic Professionals on the Gol The standout oscilloscope development of the decade Now single amp dual trace models Compare the performance then compare the price MS 15 318 MS 215 435 26 providing c oscillation over a range of frequen cies by veering the desired crystal 2 to 22 MHz OF 1 OF 1 HI Cat No 035109 Specify when ord ring 15 megahertz bandwidth Accuracy 3 full scale Internal line or external trigger Batteries and charger transformer unit included Graticule 4 x 5 divisions each division 0 25 Weight Less than 3 Ibs with batteries Size 2 9 H x 6 4 W x 8 0 D NLS products are available from Nationwide Electronic Distributors Send for our brochure today Non Linear Systems Inc Originator of the digital voltmeter Box N Del Mar California 92014 Telephone 714 755 1134 CIRCLE 34 ON READER SERVICE COUPON fot the Experimenter INTERNATIONAL CRYSTALS and KITS 02 Calibration Tolerance EXPERIMENTER CRYSTAL HC 6 U Holder 522 Cat No Specifications 031300 3 to 20 MHz For use in OF 1L OSC Specify when ordering 031310 20 to 60 MHz For use in OF 1H OSC Specify when ordering OF 1 OSCILLATOR 44 The OF 1 oscillator is a resistor capacitor circuit rys O Cat
226. ney for Direct From The Oid Sod Postage J DeNINNO amp CO Pike 5 Viewmont Village Scranton Pa 18508 717 961 0203 CIRCLE 21 ON READER SERVICE COUPON 30 TI BOOKMARK BY BOOKWORM For Project Builders A Beginner s Guide to Making Electronic Gadgets by R H Warring iS a new project by project self training course in modern electronic cir cuits and devices It has a thorough intro duction to the fundamentals lots of easy reading build it instructions and plenty of detailed circuit diagrams The book ex plores every modern circuit type and de vice and then shows how to use the infor mation learned to create more complicated and sophisticated circuits Step by step in structions backed up by circuit diagrams containing parts values show how to build a wide range of devices using all the latest semiconductors and miniature components like transistors resistors FETs capacitors etc You can build circuits like audio oscil lators transistor radio boosters DC ampli Li GODE TA AMINE FLECTROMIC EADEE Learn electronics sutra aceon ores through construction parene projects Soft cover 140 pages 4 95 CIRCLE 55 ON READER fo SERVICE COUPON fiers stroboscopes tuned amplifiers band stop filters RF and IF amplifiers Hartley oscillators telephone amplifiers light oper _ ated oscillators and output stages Published by Tab Books Blue Ridge Summit PA 17214 Audio Buil
227. nf i ILYGdN LISIT DNOS WAESTY ISILHY LHYLS YLVGA OC19 32 1 NID ZIO sick ila MSIG WOOWEd JHL YO AASA INYN AWA JHL SILONAG Ol WAY IQ 9a LHUYLS YOLIAS LNdNI SIIB tc NIHL wax St ALDI N A SNOT LINYLSNI G3S N LONI li Ya kz K sk k sk K k kok k k kok Kok oR R ORORR RK KK KORRKKOKK KK RER KRK KR WIN S I WILSAS MSIA Qt G4d4T WOOWd GNY WAY PRIA O 2 NOISHAA JISVE HS dLAS WOJ NALLIUM WAY CRIB NIY 2910 INIZVOVN SOINOULOATT AYYINIWITI WO4 WIH 1910 NYNGIIUJ AHYYT AM WAMVUGIT OISNW WIN Bale 1 pue Ajjeoyewoine jpm weigoid y S10 BUlj 1Jo 323s ys p Junes y p j j s aey noA 39uQ sunepdp A3lu BNPIAIPUL u383 Jo u j u y Aq P ururi919p oq IRA Jaquinu J3gx 3ul Buos pue 3de 10 wnqje snie Jo BUIJSISUOD S3IIJUI 1 9 duuo3 00 Z JO ss35 X Ul JO S311 U9 ENPIAIPUl 000 ode DJEPOWWOIIE HA JaySIP a suls uo pue AIOWSW JO Yp oqe ur uni IM Aavaqr isn wasAs SIP 00F d4AI WODJIg deq 94 YIM uon un uo3 ul DISV O Z UOA OD LMS 10 pousis 3q 9INSLII so 3uo 37230 JISE o noA moje pue sade pue spio331i Ino JO y n dasy yim Aavagry oisnp WVU JO Mp Olur Jats a oak aq ULI y si wesdoid y Suipniou papuajul und 3q 3 ouA ayy doop uon39 1o3 10113 3U pueg s jqerea ejep xis ss 5oid 0 WYN y3nou Ajuo s imb K lt wupaqr 31sn W weidoid s yjJUOW siy Joey ul Bu puey gjep 10 Auvu8 OISnNW polinbal Wyy jo
228. ng in the bottom of the cabinet For a future column Pll try to find some photographs and more information on these early radio phonograph combinations An Old Acquaintance One of the oldest names in radio may disappear from the scene this year In the latter part of 1978 Dart Industries purchased the stock of the P R Mallory and Co Inc Cart Industries was especially in terested in the battery division The Duracell has found wide acceptance among the consumers of America P F Mallory started the company in 1916 the year in which I was born In 1929 it moved to Indianapolis IN and a major thrust was made into the radio parts replacement market Major lines were Capacitors resistors volume controls vibrators battery chargers telephone plugs and Jacks auto radio a 2 ANTIQUE RADIO CORNER power supplies and some years later became a major battery manufacturer I started my first radio repair shop in 1935 and for many years used Malory parts exclusively I remember when the Delco Radio Division of General Mo tors Corp was buying 10 000 Mallory vibrators per day to keep Delco auto radio lines operating In recent years Mallory Distributor Products Company has been selling semi conductors security alarm sys tems recording tape and other modern products as well as their more tradi tional lines of replacement parts Only time will tell if the Mallory name sur vives in the future of electroni
229. ngineers Loop Antenna The single transistor radio type battery used for the power supply is secured to the rear apron with a U clip Current drain of the internal amplifier is very low and the bat tery should last many months if not its shelf life depending on use The UHF con nector is the amplifier output tenna was digging out signals we didn t even know existed Maybe if we had a longwire antenna we would receive those magical signals we received with the Palomar But in this age of apartment houses with sealed windows condominiums where you can t hang anything out the win dow townhouses where any form of wire or antenna brings petitions of pro ELEMENTARY ELECTRONICS May June 1979 test from the other side of town and private homes with backyards no larger than a postage stamp the longwire antenna is fast becoming a legend from the golden days of radio Most BCB DXers are relegated to a piece of wire lying on the floor or concealed under the carpet for a skyhook The Palomar Engineers BCB Loop Antenna System has come to the res cue The system consists of two sep arate devices The first is a loop ampli fier a metal cabinet 71 4 x 6 x 21 4 inches that houses a broadband pre amplifier tuning capacitor and power switch The 9 volt battery power sup ply mounts on the back adjacent to a standard coaxial connector used for the output The top of the cabinet has a phone type jack mounted in the ce
230. nics From the first com puterized personal weather station to the first computerized color TV you can program for an entire evening s viewing Heath leads the way in sophisticated quality electronics And every Heathkit product comes with their world famous step by step instruction manual that makes building any Heathkit product fun and easy So send for your Heathkit catalog today and choose from nearly 400 fully illustrated and described kits that will give you the pride and satis faction of saying I built it myself wet PUT MAN ORDER CATALOG NO n petted eo eee j aap BIg X Building Heathkit products is a great family affair There s nothing better you alweys end up with top quality im SEND FOR YOUR FREE COPY TODAY equipment at low kit prices serial noon comer miia C4 G all in this FREE CATALOG Please send me my FREE Heathkit Catalog am not now esting SO your catalogs get yours now ae hy Address l If card or coupon z is missing write CGiy k yo a O taanF R Heath Company Dept 139 530 ae s Benton Harbor Michigan 49022 L f L E BES m GSS nnmnnn GE HES GSS HSE SS ELEMENTARY ELECTRONICS May June Toro COCER eee m s kia SAV L Enclosed is 2 98 for 6 issues of HFSBG outside U S A possessions send 4 00 You may use Master Charge or Visa card PECERA JIA LEETE EXPIRATION DATE SIGNATURE a
231. noise One of the devices that provides both dynamic range expansion and high fre quency noise reduction in a single mod ular component is the Heathkit Model AD 1304 Active Audio Processor The AD 1304 is a line level device that connects between an amplifier s or receiver s preamplifier output and main This block diagram shows how the Audio Processor is connected to various com ponents in your hi fi system It acts to expand and filter inputs from all audio sources TAPE AUX TAPE OR AUX 2 INPUT SELECTOR amplifier input This is generally ac complished by using the amplifier s tape connections and the associated tape moniter switch same way you d switch any other line level accessory The tape monitor connections are simply moved to the audio processor Three Functions This in line con nection permits the AD 1304 to pro vide any combination of three func tions dynamic range expansion noise reduction high frequency filter A sep arate on off switch is provided for each of the functions The dynamic range expansion is ap plied to both the signal peaks and the lowest volumes in such a way that the norma dynamic range of the signal source is increased by approximately 7 dB at midband frequencies Figure 1 shows how this is done TAPE RECORDER pee INPUT OUTPUT O ACTIVE AUDIO a eee PROCESSOR TAPES TAPES wer Li OUT MON 4 x PROCESSOR OUTPUT o A Tape C
232. nsmitters are at the same loca tion a technical malfunction can cause mixing right at the transmitter site in which case it is usually referred to as cross modulation We once found VOA Greenville transmissions on 15140 and 15280 interfering with WWV on 1500 kHz 2x 15140 minus 15280 Neither 15140 nor 15280 were any where near strong enough to overload our receiver so the Greenville signal on 15000 was obviously real On medium and long wave cross modulation oc casionally occurs in the ionosphere the Luxembourg effect This has been extremely rare in North America due to the absence of super powered trans mitters which can quite literally over load the ionosphere We have not seen the Luxembourg effect reported on short wave in any part of the world Still More Complex Certain other minor receiver defects can create some outrageously exotic mathematical com binations Minute radiation from the 455 kHz intermediate frequency ampli fier can mix with incoming signals and the local oscillator may radiate at its second harmonic Suppose a listener in the Buffalo N Y area is tuned to 1495 kHz Hts local oscillator will be at 1950 kHz 1495 plus 455 and its second harmonic will be at 3900 kHz 2 X F950 Meanwhile there is a powerful local WKBW on 1520 kHz and an other CHOW on 1470 kHz If WKBW overloads the receiver we have the equation 3900 1520 1470 455 455 kHz
233. ntenna brochure is available from Shakespeare Gives complete specs and polarization radiation patterns nor their new fiberglass directional antennas 371 Your computer system needn t cost a fortune Southwest Technical Products offers their 6800 computer complete at 395 with features that cost you extra with many other systems Peripheral bar gains are included here eo R j 374 Radatron s Catalog 1006 lists many projects from a self contained portable lab station for an electricity electronics course to many texts lab manuals and applied activities 306 Antenna Specialists has a new 32 page CB and monitor antenna catalog a new amateur antenna catalog and a complete accessory Catalog 307 Atlas calls their 210X and 215X the perfect am ateur mobile rigs Their 6 page full color detailed spec sheet tells all Yours for the asking 330 There are nearly 400 electronics kits in Heath s new catalog Virtually every do it yourself interest is included TV radios stereo and 4 channel hi fi hobby computers etc 308 Your guide to equipment for radio communi cation is an informative product booklet offered by R L Drake Co Hams and SWLers alike should scan this 20 page shopper s guide 310 New and used personal computer machines and peripherals you never dreamed existed o were available are in the Newman Computer Exchange catalog Get yours today 311 Midland Communications line of base mobile and hand
234. nts to be made in future frames Observe how the collector voltage Vc drops toward 0 V as the currents are increased If you do not Have the facilities for setting up the circuit and measuring the values just read through the experiment to find out how it would be done If you do have the facilities you will need the following equipment and supplies 1 9 V transistor radio battery or a lab power supply 1 current meter maximum reading 100 uA 1 current meter maximum reading 10 mA voltmeter maximum reading 10 V 1 resistor substitution box ora 1 MQ potentiometer or assorted resistors with values in the table 1 1 k2 resistor 1 transistor preferably NPN Almost any small commercially available transistor will do for this experiment The measurements given in this book were obtained using a 2N3643 If only a PNP is available then simply reverse the battery voltage and proceed as described Finally you will need several clip leads to join the components together If you have ag nate facilities soldered joints can be used i Set up the circuit shown in the figure below Follow this procedure 4 Y ELEMENTARY ELECTRONICS May June 1979 cae 1 Set Rb to its highest value 2 Measure and record b in the table on page 55 3 Measure and record Ic 4 Measure and record Ve 5 Lower the value of Ab enough to produce a dif ferent reading of b 6 Measuer and record b Ic and V
235. nuary 1 1973 the voltage must not exceed 0 75 VRMS This corresponds to 0 5 mA AC tickle charge and is not excessive or dangerous If your receiver exceeds this value look for the fault or short Sets built iy TOUCH PROBE TO EXPOSED METAL PARTS OF RECEIVER GOGO EARTH GROUND SUCH AS A WATER PIPE prior to 1973 may test high as 7 5 VRMS Legally this is okay but by current standards it Is unsafe Parts Seeker Hank I picked up a copy of the maga zine 99 IC PROJECTS and I want to get into them right away Unfortunately it s tough buying semiconductors in Columbia Falls Montana So give me a basic list of parts suppliers that I should contact D J Columbia Falls MT Here are a few parts ad equipment sup pliers in alphabetical order 1 Aldelco 228 E Babylon Turnpike Merrick NY 11566 2 AP Products Box 110 72 Corin Dr Painesville OH 44077 3 Continental Specialties Corp 70 Ful ton Terrace Box 1942 New Haven CT 06509 4 Cornell 4219 E University Ave Diego CA 92105 5 Digi Key Corp P O Box E77 Thief River Falls MN 56701 6 ETCO Electronics Dept 024 North San Country Shopping Center Plattsburg NY 12901 7 Jamesco Electronics 1021 Howard Ave San Carlos CA 94070 8 Lafayette Radio 111 Jericho Turnpike syosset NY 9 Poly Paks P O Box 942 N9 Lynn field MA 01940 10 Radio Shack One Tandy Cen
236. obile antenna and a typica imported base loaded antenna LITERATURE LIBRARY 328 If you are into audio ham radio project build ing telephones CB or any electronics hobby you ll want McGee s latest catalog of parts and gadgets Hard to find parts fill each page so get a copy of the catalog from McGee today x 329 Semiconductor Supermart is a new 1979 cata log listing project builders parts popular CB gear and test equipment It features semiconductors all from Circuit Speclalists 333 Get the new free catalog from Howard W Sams It describes 100 s of books for hobbyists and technicians books on projects basic elec tronics and related subjects 354 A government FCC License can help you qualify for a career in electronics Send for Infor mation from Cleveland Institute of Electronics 355 New for CBers from Anixter Mark is a colorful 4 page brochure detailing their line of base station and mobile antennas including 6 models of the famous Mark Heliwhip 356 Now you can get the Break through Book with its 105 innovations in breadboarding and test _ing Continental Specialties The break through is twofold products and price 359 Electronics Book Club has literature on how to get up to 3 electronics books retailing at 58 70 for only 99 cents each plus a sample Club News package ri 362 B amp F Enterprises Truckload Sale catalog of fers 10 off all merchandise
237. ok concentrates on the properties and limitations of real trans mission performance The book discusses filters equalizers and other corrective de vices from the user s point of view and explains the use and testing of modems and other terminal equipment ASCII codes and detailed guides to interpretation of com munications circuit specifications are pre sented Review questions stressing key concepts are included Published by E amp L Instruments Inc 61 First St Derby CT 06418 B ELEMENTARY ELECTRONICS May June 1979 HHI W bce a SEES a ie COLOR PART NO BLUE JW 1 B WHITE JW 1 W YELLOW JW 1 Y RED JW 1 R a BLUE R JW B WHITE R JW w YELLOW R JW Y RED R JW R ek n 4 JUS WRAP TOOL WITH T WHY CUT WHY STRIP WHY SLIT WHY NOT T AWG 30 Wire 025 Square Posts Daisy Chain or Point To Point JUST WRAP m Built In Cut Off e Easy Loading of Wire e Available Wire Colors Blue White Red amp Yellow ONE 50 FT ADLL OF WIRE US LIST PRICE WIRE 50 FT 14 95 14 95 14 95 14 95 REPLACEMENT ROLL OF 2 98 2 98 2 98 2 98 DA SY CHAIN E USA FOREIGN PATENTS PENDING No Striping or Slitting Recuired 1495 POINT TO POINT OK MACHINE amp TOOL CORPORATION 3455 CONNER ST BRONX N Y 10475 212 994 6600 TELEX 125091 MINIMUPA BILLING 25 00 ACD SHIPPING CHARGE 200 NEW YORK CITY STATE RESIDENTS AD
238. on 10 O4Y FREE TRIAL ALL BOOKS 100 GUARANTEED You must be satisfied or return the books and we ll cancel the invoice COMPUTERS MICROPROCESSORS amp ROBOTICS 1071 The Complete Handbook o Hobolics 364 p 137 l 1085 24 Tested Ready To Run Game Programs in BASIC 252 p 1070 Digital interfacing with an Analog World 406 p 277 il 1088 Illustrated Dici of Microcomputer Termindogy 322 p 150 1076 Aniticial tnteiligence 252 p 1181 841 Build Your Own Working Robot 238 p 117 i 1099 How To Build Your Own Working 16 Bil Microcanputer 80 p 1095 Programs in BASIC for Elec Eng Techs amp Exp t30p 49 1077 Hdbk of Remote Control amp Automation Techs 294 p 250 1 1055 Tne BASIC Cookbook 140 p 1015 Beg nner s Gde to Computers amp Microprocessc s 308 p 1000 57 Practical Programs amp Games in BASIC 210 p 64 995 Beginner s Guide to Microprocessors 182 p 36 985 Programming Microprocessors 280 p 102 676 Simplitted Computer Programming Including RPG 971 Miniprocessors tram Calculators to Computers 196 p 874 Master Handbook of Digital Logic Appic s 392 p 287 ul 952 M processor Programming tor ane Hobbyists 387 p 955 Modern Digital Communications 308 p 122 l 975 The Compulator Book Build Super Caiculators amp Minicomputer Hdwe with Caiculaior Chips 322 p 227 i 752 Computer Programming Handbook 518 p 114 l 554 Computer Technician s Handbook 480 p 428 824 Advan
239. on CB electronics braad casting do it yourself hobby radio TV hi fi and CB and TV Servicing 338 Break Break a booklet which came into existence at the request of hundreds of CBers con tains real life stories of incidents taking place on America s highways and byways Compiled by the Shakespeare Company it is available on L Yirst come first serve basis 345 For CBers from Hy Gain Electronics Corp there is a 50 page 4 color catalog base mobile and marine transceivers antennas and accessories Colorful literature illustrating two models of moni tor scanners Ts also available 323 Lafayette Radio s 1979 catalog offers almost everything in hi fi CB ham and many electronic parts A product index will help you find anything from auto equipment accessories to wire wrapping tools 381 Fordham Radio s handy catalog covers test instruments tools parts home and car audio prod ucts scanners and lots more Get your free copy today 385 Amateur Radio buffs and beginners will want the latest Ham Radio Communications Bookstore catalog It s packed with items you shou d be read ing today y 373 48 page Electronic Things and Ideas Book from ETCO has the gadgets and goodies not found in stores and elsewhere 382 Buys by the dozens in Long s Electronics super Ham Radio Buyer s Guide Good reading if you re in the market for a complete station or spare fuses 383 If you re a radio co
240. onal Q code and sche matic circuit diagram symbols Names of club members providing correct re sponses are put In a container and a drawing is held to select the pennant recipients The BBC issues verification QSL cards only on special occasions One 7 ob bf bebt ws Henry Hatch the resident engineering personality of the World Radio Club demonstrates a crystal receiver of his own design The BBC s worldwide reputation y clear accurate and non political news Pran deastare is due to its large staff of highly trained and motivated reporters editors and announcers such opportunity occurred in 1972 when the parent BBC organization celebrated its fiftieth anniversary of go ing on the air Annually in the summer another chance for a BBC QSL is offered when the World Radio Club holds its mem bers only DX Award competition Cer tificates are awarded to DXers who correctly report reception from vari ous BBC transmission sites during the two week contest period Dates times frequencies and transmitter locations are typed on the attractive 81 2 by 10 inch award certificates Contemporary rock music found on the international charts is played by Brian Matthew during his Matthew on Music program heard Wednesdays fol lowing World Radio Club The BBC World Service is one of only a handful of sources for radio drama today Programs called Radio Theater and Theater of the Air are heard
241. ons with ease Tube Preparation Select a defective radio or TV tube with a bakelite base The larger the glass tube the greater building area for the small radio com ponents An antique radio tube is ideal but not necessary If you can t find one in the junk box check with your local H AVE YOU EVER seen a mode ship Getting burned by the high cost of electricity Go Sun Power SOLAR SWINGER Radio TV shop they may throw out several hundred of these old tubes ev ery year There are many oid power output tubes available such as 6L6G 6C6G and 5U4G Don t select a 6BK4 type as you cannot remove the top metal anode from inside the glass envelope You may use a large tube 6LQ6 with a glass base and then mount it on top of a black tube base Pickup five Or six old tubes to practice on Before attempting to remove the bakelite base from the tube let air into the bottom of it All radio and TV tubes operate with an internal vacuum the air having been pumped out A small glass seal is located at the bottom of the tube Always wear a pair of gloves when working around glass or warm compo nents Now you want to let air back inside the tube Break off the black bakelite center key locator between the tube side the tube Break off the black bake lite center key located between the tube ELEMENTARY ELECTRONICS May June 1979 prongs You should see the pointed glass seal Take a pair of long nose pliers and break of
242. opy Sales Dept 380 Lexington Avenue New York NY 10017 Don t hesitate they sell out pretty quick Charter Reader Your November December 1978 issue announced the 15th anniversary of ELE MENTARY ELECTRONICS still have your first 1963 issue and continue to endl it very interesting This premier edition gave me my first knowledge of electronics maga zines I would just like to mention that although I haven t written for information I still find the answered questions very in formative Thanks for having this column in the magazine L ELEMENTARY ELECTRONICS INDEX TO ADVERTISERS lt 2 RS ADVERTISER PAGE AT VACTIVG DNC CTMONIGS s uu u u dae u 1 s 93 24 Antenna Incorporated 8 9 26 Ap TUNES U cscs cece ee R shu cas 27 Bl PANN Be aces Y Sapu 1 umma ou See Aba 14 BAB EMGCRBTISOS J UU u Whom m uA 3 90 22 BERIK arecisijgrr n s NB U a AO 34 Cleveland Institute of Electronics 4 7 SC 2 eee ee DVD U P 38 CV2 7 Continental Specialties CV3 39 Dak Industries e U T u sm m Re 35 Sb IDNO MBamesS l sh us ea a Ana 30 23 Digi Key ee ee ee ee ae 89 30 ee COTE a ee ee ens 25 a ee maw CS E 16 9 aaron Eiffe aseo uum as n la ode ye E 18 SO le eee e a mo 32 25 Gilfer viene laqakuna Qk p laqa a a aa 30 S RG od FEO a cc Sotiris n a ma 3 TL Grantham Colleget ss
243. or the DX station to reply to You can be first on the list so why wait Regardless of how many other sta tions might be waiting to work him always get the QSL routing information SINGLE SIDERAND y x The Radio Amateur s Handbook and Understanding Amateur SSB are excellent examples of the educational material available ELEMENTARY ELECTRONICS May June 1979 from your DX contact Not only do you get the information you need but you perform a service to the other operators waiting on frequency by al lowing them to copy it also Making the DX station repeat it a few times is always a good practice Sometimes their English ain t too cool On VHF FM Repeaters Always initi ate a conversation by calling CQ It s foolish to announce that you are listen ing on the frequency because if you re not talking it s obvious that you are indeed listening Calling CQ will iden tify you as an A 1 HF operator Once you have the repeater keep the pauses between transmissions to an ab solute minimum because there s always the possibility of losing the channel to someone else First come first served Also don t be misled by those people who yell emergency That s just a ruse to get you off and get themselves on If there s a real emergency they can use the landline That s what it s there for Conclusion Obviously this has been a guide towards what not to do and you can probably add to i
244. ork ng circuit A Vy B Ca prot There are 9 Proto Boards in alll manufacturers suggested U S resale prices from 15 95 to 124 95 70 Fulton enge New agen CT 06509 203 624 3103 TWX 710 4E amp 1227 OTHER OFFICES San Francisco 415 421 8872 TWX 9 0 372 7982 Europe CSC UK LTD Phone Saffron Walden 799 21682 TLX 817477 Sugges ec US resale Available at selec ed local aastributors Canada Len Finkler Ltd Ontario L gt cs specific ctions subject to change without notice 1 800 243 6077 ee eee nea pec a Led s I 3 Call toll free for details CIRCLE 7 ON READER SERVICE COUPOM LASS fz Bitten UVM gee dived ca J apie Miniaturization breakthrough Realistic s tabulous new System Seven combines beauty elegant small size and a level of acousti cal quality you ve never heard until now in low priced book shelf stereo Svstem Seven includes our new STA 7 AM FM receiver 10 watts per channel minimum RMS into 8 ohms 20 20 Q000 HZ with no more than 0 5 At last true hi fi perfectly sized for a bookcase The 4 1 2 lb speakers can even be used for bookends Sold only at tare amu awani sip nwa ne p Realistics System Seven a new size and shape for stereo total harmonic distortion and a pair of our amazing Minimus 7 speaker systems teaturing large excursion woofers and sott dome tweeters in diecast enclosure
245. oscillator In the simplest radio what ever frequency you are tuned to the T MOST ANNOYING PROBLEM faced i gana tretel at z ie pagi SEHE i 4 Ea as VAL AI V local oscillator will operate exactly 455 kHz higher Thus if you are tuned to Radio Surcolombia on 5010 kHz your local oscillator would be on 5465 kHz The two are combined in your receiver s mixer circuit producing of course that desired 455 kHz intermediate fre quency usually referred to as the IF From there on all amplification circuits in the receiver except those in the audio section can be pre set to this fixed IF Equally important selectivity the ability to separate the desired sig nal from those on adjoining frequen cies is considerably better at 455 kHz than on higher frequencies Suppose while you are listening to Radio Surcolombia on 5010 kHz and your local oscillator is at 5465 Radio Moscow has a strong signal on 5920 kHz 5920 just happens to be 455 kHz above 5465 so if it mixes with your local oscillator it will also produce an intermediate frequency of 455 kHz In other words Radio Moscow s 5920 Like mirages in the desert radio stations are not always where they appear to be sp ii H nina by C M Stanbury ELEMENTARY ELECTRONICS May June 1979 i wa D ollo E signai will show up as an image on 5010 kHz Note that resultant frequen cy relationship this
246. ove such a program will consist Of instructions and data The instructions are binary codes that cause the CPU to perform certain operations on the data There ts a limited number of instructions any given CPU can per form and the list of these instructions IS known as the ivstruction set for that CPU A computer program is a list of ap propriate instructions also known as opcodes and their operands or data the CPU needs to carry out the instruc tons stored in an orderly manner in memory To execute the program the program counter goes to the address of each in struction in turn loads that instruction Into the instruction register and then goes to the address of the next instruc tion The instruction in the instruction register is decoded by the instruction decoder and executed and the process is repeated until a programmer s error Is encountered and the machine gets confused Figure 2 PROGRAM When writing progranss such as these in machine language the individual CPU s architecture is a major consider ation The nature of the machine s in struction set is based upon its architec ture and in order to program for a ditferent CPU a different instruction set must be learned High level lan guages like BASIC and PASCAL allow us to communicate in English like state ments of the problem The interpreter or compiler translates the program into machine instructions the CPU can un derstand For our purposes
247. p Laurenceau Box 1325A Long Island NY 11101 AUTHOR S SERVICE PUBLISH YOUR BOOK Join our successful au thors Publicity advertising beautiful books All sub jects invited Send for fact filled booklet and free manuscript report Carlton Press Dept SMQ 84 Fifth Avenue NY 10011 j BIG MAIL RECEIVE MONEY MAKING OPPORTUNITIES Your name placed with 2 000 tmporters wholesalers manufacturers etc Year listing 1 00 SAVE 160 00 Postage Advertising Agency Box 123 YNA We nonah NJ 08090 BLUEPRINTS PATTERNS amp PLANS LINEAR AMPLIFIERS 100 or 200 watt 2 30 MHz Omnipolarized ANTENNA 300 MHz COUNTER Mod ulation BOOSTER VOX Plans 3 00 each 10 00 ail Catalog of others PANAXIS Box 130 GE5 Paradise CA 95969 ELECTRONIC Gas Detector Plans with IC ampli fier included 2 50 JR Industries 5834 Swancreek Toledo OH 43614 i 1 NEW CRAFT PRINT CATALOG Choose from over 100 great easy to build plans Send 1 50 completely refunded with your first order BOAT BUILDER CP Div 380 Lexington Ave New York NY 10017 BOOKS amp PERIODICALS FREE CATALOG SELF IMPROVEMENT BOOKS The Mail Sack Dept 1379 600 Welch Blvd Flint MI 48503 BUSINESS ADVENTURES FREE book cata logue SIMTEK Box 109 M Cambridge MA 02139 BE A WINNER Make fortunes winning contests sweepstakes etc Unique Books Show How Free Cata log A amp W Enterprises 14 Auriga La Sewell NJ 08080
248. p of 10 to cover handling No stamps please Allow 4 6 weeks for delivery 301 302 303 305 30 30 316 318 320 321 322 323 345 354 355 356 359 373 374 375 377 378 379 300 J Enter my subscription to ELEMENTARY ELECTRONICS for 9 issues at 5 97 Check enclosed Add 1 00 for Canada and all other countries ga NAME print clearly ADDRESS m kama Gas iss sana xuma asan sssi E ee sss sss usq pas Bas maq Be ss Essl Essl sasi o CITY t MAY JUNE 1979 Void After October 16 1979 308 310 311 312 313 314 327 328 329 330 333 335 362 364 365 366 371 372 380 381 382 383 384 385 H9E037 STATE ZIP x ELEMENTARY ELECTRONICS May June 1979 95 Classified l MAR KET ELEMENTARY ELECTRONICS is published Bi monthly The rate per word for CLASSIFIED ADVERTISEMENTS is 1 30 payable in advance minimum ad 15 00 Capitalized words 40 per word additional ADDITIONAL INCOME MECHANICALLY INCLINED INDIVIDUALS WANTED ASSEMBLE ELECTRONIC DEVICES IN YOUR HOME Get started in spare time Experi ence Knowledge or Investment Not Necessary Ex pect big profits 300 600 Wk Possible Write for free literature tellmg how Electronic Development Lab Box 1560E Pinellas Park FL 33565 200 WEEKLY BECOME COMMISSION MAILER Wa SS GRAHAMS DPBX 99371 TACOMA 98499 MAKE ONE MILLION DOLLARS the lazy way Mailing Circulars Permanent Homework Send Stam
249. p sum it is cheaper in the long run than shelling out a hun dred dollars here for software and an other couple of hundred dollars there for an interface or two But probably the biggest factor in my choice of Processor Technology s SOL 20 was the praise my friends had for this company s VDM and CUTSboard as well as their software including the SOLOS monitor program Several of them have files full of Processor Tech nology material I am fortunate here in Toronto as there are three computer stores that sell the SOL 20 All were very helpful and their prices were very close Here again I relied upon the advice of a friend who had dealt with them and chose The Computer Place on Queen St West here in Toronto I found their after service advice invaluable and they checked my results twice when my troubleshooting ability failed The kit came packaged in the orig inal air cargo container The flight crew could have kicked this well packaged box safely out the cargo door without doing any damage However I was a bit discouraged to find a revision notice right on the outside of the shipping box What lay ahead A x ee oa by Bruce Evans A CIRCLE 70 ON READER SERVICE COUPON The Hobb wri ig ag A a aa sak ms s a s aa a ead Ui qiw s E qomi Ma omputer One COLution A user builder report on the Processor Technology SOL 20 home computer The individual components were all of excellent
250. payment on an international bank draft or international postal money order In American dollars BAXTER CENTRE 1050 BAXTER ROAD OTTAWA ONTARIO K2C 3P2 Tel 613 820 9471 CIRCLE 4 ON READER SERVICE COUPON 93 Solar Swinger Continued from page 67 work cloth under the wooden base to protect the soft wood from scratches and dents Cut a 14 hole about 1 4 deep for the tube base The 1 4 indentation will take a large pasteboard washer to bolt the tube socket into position Finish drilling out the l inch hole for the tube prongs to fit comfortably inside De pending upon the size of the tuning capacitor lay it upon the bottom area and drill a large hole to enclose the whole body Do not drill clear through the board but leave about 14 at the top side for the mounting area of the tuning capacitor The tuning capacitor and the head phones are the only components mount ed outside of the tube envelope A small 4 hole is drilled in the center and at the rear of the base towards the tube socket The headphone and an tenna wires will feed through this area to the tube socket pins Cut a groove into the wood area between the capa citor and tube socket hole The capa citor s two small connecting wires will lay flat in this groove If needed sand down the top of the wooden base area with fine sand paper Stain varnish or spray paint the top side Choose a light color spray paint
251. perate under a table lamp After all adjustments are made spread silicone cement over the tuning capacitor wires Cut out a large paste board or plastic washer and place it over the tube pins Use the 34 inch ma chine screw and bolt the tube socket into position To keep the earphone wires from pulling out apply silicone cement in the small hole Place four rubber grommets or metal spacers on each corner for feet and cement in place Let the radio lay upside down until the silicone cement sets up The glass envelope should be mounted last and glued to the tube base with black silicone cement Place CB Xcvr Checkout Continued from page 76 clock alert operation Standard ac cessories include a microphone and an AC power cord Receiver Section Test Input sensitivity 0 5 nV Adjacent channel rejection 64 dB AGC action 7 rr 1 5 dB SSB opposite sideband rejection oo 50 dB Input level for S6 meter MGIGATOM co ce nee a 350 zV Reading compresses above S6 Transmitter Section Test AM RF output 3 8 watts SSB RF output _11 watts P E P Modulation to 85 ooo yes Relative sensitivity for 85 Liu u I u a Kas a sN 25 dB Modulation limited to 100 Editorial Remarks The CB555 has a relative reading S meter jacks for P A and remote speakers L E D digital channel indicator S RF SWR meter CLOCK alert which will automatically turn the
252. performance in a lightweight com pletely portable package on 2 meter FM With the flexibility of six crystal control led channels three installed the unit may be powered with eight nicad size AA ceils or seven alkaline dry batteries to provide 1 watt output Options in clude external speaker microphone battery charger and leather carrying case The FT 202R comes with the Rubber Ducky antenna dummy bat tery vinyl carrying case and shoulder strap and sells for 199 00 Bat Continued on page 87 18 CIRCLE 18 ON READER SERVICE COUPON ELEMENTARY ELECTRONICS May June 1979 HOT NEW BOOKS FOR sega dee tte PROS The latest in fis fais books that people waited in line to buy How to Buy amp Use Minicomputers amp Microcomputers By W Barden Ur Explores the basics covers hardware software peripheral devices programming languages amp techniques use for fun or profit 240 pgs 21357 9 95 Microcomputer Primer By M Waite amp M Pardee Explains it all central processing unit mem ory input output interfaces programs Dis cusses well known models amp shows how to program your own 224 pgs 21404 7 95 Basic Primer By M Waite amp M Pardee Covers BASIC fundamentals program con trol organization functions amp variations With a game Ps Ald amp data on numbering sys tems amp ASCII Character codes 192 pgs 21586 8 95 How to Program Microcomput
253. phically shows how the amplifier performs in order to create the most acceptable sound for individual listening tastes As the controls of the GE 500 are moved to ELEMENTARY ELECTRONICS May June 1979 adjust for tone an illuminated fiexible rod changes its shape in conformance with the control movement The GE 500 contains integrated circuitry for maxi mum reliability wide frequency response and 40 20 20 watts of undistorted RMS stereo power Other features in clude slide controls that infinitely adjust five different frequency bands a front to rear fader control a power indicator light and an audio by pass switch The unit can be used with all tape decks and radios and with all speakers that have a power handling capability of 15 watts or greater Suggested retail price is 89 95 Get all the facts direct from the Sparko matic Corp Milford PA 18337 On the Road Convenience Courier has added a new mobile AM SSB transceiver to their line The Courier Galaxy is a straight forward under dash unit with features designed with the operator in mind It has controls for noise blanker SWR calibration clarifier mic and RF gain and PA capability The Galaxy also has a large LED channel in dicator and a three in one SWR calibra tion and S RF meter One popular fea ture is a channel 9 priority switch that CIRCLE 78 ON READER SERVICE COUPON allows selection of channel 9 without tuning the dial Its suggested
254. ple convenient operation It sells for 259 95 FOB Benton Harbor MI For more_information on the new low cost 10 4205 Dual Trace Oscilloscope kit send for the latest Heath kit catalog Write Heath Company Department 570 130 Benton Harbor MI 49022 2 Meter Yagi Antennas Two models of the new Star Tracker se ries of Hustler 2 meter yagi antennas are 5 and 11 element rotatable beam an tennas They are completely tuneable from 144 148 MHz with an unique ad justable matching system for 1 5 1 or better SWR At resonance SWR is typi cally 1 1 1 This system provides for optimum energy transfer without sacri ficing gain or pattern contro Each model can be easily mounted for vertical or horizontal polarization for station to sta tion VHF DX work The Star Tracker CIRCLE 43 ON READER SERVICE COUPON Model ST 5 is a compact 54 inch 2 meter beam with 5 optimumly spaced elements Forward gain is greater than 10 dB and the front to back ratio is greater than 22 dB over the antenna s 4 MHz bandwidth Half power beamwidth is normally 50 The Model ST 11 Star Tracker is a 144 inch center mounted 11 element beam Optimum element spacing provides a forward gain of greater than 13 dB Front to back ratio is greater than 27 dB over the 4 MHz bandwidth Half power beamwidth is normaily 36 Hus tler furnishes all stainless steel hardware and the corrosion resistant steel clamps There are no mounting holes in the el
255. pport wire terminals Place a piece of spaghetti over the col lector wire of Q2 and solder into pin terminal 4 if it is long enough If not lengthen the terminal wire with a piece of hookup wire Connect the small diode between the coil tap LI and the base terminal of Q1 Slip a piece of spaghetti over the wiring to prevent touching of other components Mount the solar cells last inside the tube area Be careful to observe cor rect wire polarity The positive terminal will solder to terminal 1 and the nega tive wire to 6 After all wiring has been completed inside the tube socket dou ble check each component and tie wire before bolting to the wooden base Now tack the antenna coil LI and solar cell into position with a dab of silicone cement Base Layout You may pick up a wooden base mounting plate at any novelty or hobby store Ours was 634 by 4 and cost 99 cents They may come in many sizes and shapes with a higher or lower price tag Mark the parts layout on the bottom side of the wooden base The tube socket may be mounted 11 2 from the rear and in the center of the base plate Place a Continued on page 94 67 in searchof kind and the hero of every kid of the 1930s who made rotten egg smells and burned holes in his bed room curtains with a chemistry set All over the country knee pants test tube Shakers dreamed of one day making great scientific discoveries for the bet terment of mankind And in
256. pro vide from 60 to 80 hours of continuous use The mike is continuously tunable to any frequency between 88 and 108 MHz the full FM broadcast band Semiconductors in the mike include an FET one IC one diode and three silicon transistors The modulation bandwidth is 100 kHz and the field strength is 50 microvolts meter at 50 feet open area It incorporates an electret microphone has a permanent ly attached 4 wavelength flexible wire antenna 29 inches long and has FCC 44 E A type approval The first thing we liked about this compact little marvel is the slide switch which helps prolong the life of the bat tery without the need to remove it We were equally impressed by perform ance With the receiver volume set only about one eighth of maximum the noise could be monitored anywhere in the house even throughout the base ment area By turning the receiver vol ume gradually to maximum clear pick up was possible everywhere on the one acre of property The test was made at 108 MHz because the manufacturer recommends you start from this end of the FM band in the search for the first quiet zone Micro Mini Mike AMC Sales 18 95 plus 1 postage and handling Model WM F2 measures 2 inches by inches by inch cubic inch This second smallest factory built mike features a durable black metal case 1 3 volt mercury battery 27 inch flexible wire antenna and the following semiconductors one FET
257. quency the resultant het will vary in pitch as you tune across it unless the image is caused by a pulse modulated station such as Beran or shortwave radar If while listening to Radio Surco lombia on 5010 kHz there is a het turn the dial slightly If the het varies in pitch it is being caused by the Radio Moscow image or some other strong station on 5920 If the het remains constant then there really is a second station within a few kHz of 5010 Some Strategy Short of actually modifying your receiver or buying a new one your most important defense against images caused in your local os cillator is the antenna tuner knob De termine which antenna setting is best for each band or more precisely the best setting for eac MegaHertz If you find two stations and know that one is an image but don t know which the rea signal will be strongest at the proper antenna tuner setting while the _image will be strongest at a slightly different setting The next step is to eliminate the het you can Tune the dial very carefully until the pitch of the het drops to zero Un fortunately most inexpensive receivers are a bit unstable so you may have to repeat this process every few minutes However if the image is caused by a broadcast station or even some utility stations with voice modulation the worst of the interference will be elimi nated so it is worth the effort If the image is from fradioteletype facsimile
258. r Radios You Can Build 40 p 122 d 86 1 Display Electronics 252 p 195 l 679 Electronics for Shutterbugs 204 p 109 t 771 integated Circuits Guidebook 196 p 119 667 Miniature Projects tor Electronic Hobbyists 168 p 77 l 787 OP AMP Circurt Design amp Applications 280 p 2391 796 MOSFET Circuits Guidebook with 100 Projects 322p 199 ii 714 Radio Astronomy for the Amateur 252 p 88 1 571 RAadio Electronics Hobby Projects 192 p 214 l 591 Solid State Projects for the Experimenter 224 p 228 il 780 111 Digital amp Linear IC Projects 210 p 2441 699 Sold State Circuits Guidebook 252 p 227 l 524 104 Easy Projects tor Electronics Gadgeteer 160 p 105 d 53 Electronics Seif Taught with Exp amp Projecls 288 p 1911 695 Practical Triac SCR Projects for Experiment rs 192p 14 486 104 Simple One Tube Projects 192 p 1041 629 Handbook of IC Circuit Projects 224 p 136 if 487 64 Hobby Projects for Home amp Car 192 p 195 537 125 One Transisior Projects 192 p 125 11 83 Fun with Electricity 128 p 94 it 647 Stereo Quad Hi Fi Principles amp Projects 192 p 100 l 464 Electronic Hobbyisi s IC Project Handbook 154 p 86 il 613 New IC FET Principtes amp Projects 154 p 60 462 104 Easy Transistor Projects You Can Build 224 p 105 4 590 Practcal Solid State Principles amp Projects 176 p 127 568 iC Hrojects for Amateur amp Experimenter t92 p 252 t 42 Transistor Projects tor Hobbyists amp
259. r frequency Sure if you plunk yourself down in the middle of one of the amateur bands you can be reasonably certain that if other stations don t get on your back you re somewhere in a legitimate seg ment of the band But there s no way you re going to crowd the edges of the bands where much DX hangs out or accurately zero beat a net without a frequency counter built into the trans ceiver or transmitter or an external counter And unless you re in the mark et for one of those new digital readout transmitters priced close to 1000 the external counter is your best bet It certainly beats asking the receiving sta tion if you re on frequency for his re ceiver is most likely no better cali brated than your transmitter Why a Counter Most important pre cise transmitter frequency is often re quired for proper reception For ex ample many modern AM CB trans ceivers are so selective that even with delta tuning a transmitter near the frequency toleranec limits will be re ceived with spitty garbled modula tion Even worse SSB requires the transmitter carrier be well within toler ance for the receiver clarifiers often cannot properly tune a signal near the tolerance limits and what you hear in this instance is a high pitched Donald Duck sound For best reception on the receiving end a modern CB transmitter should be within about 1000 Hz of the channel frequency If it gets beyond these limits you r
260. radio to the auxiliary input of a tape recorder You can then wander anywhere in the house and dictate in formation onto tape It s an easy way to make an inven tory of personal possessions without lugging around the whole tape recorder Choose Optimum Range Our ex perience indicates that the factory built wireless mikes have substantially great er range than the kit jobs In some applications you need that extended reach but in other situations it could be a handicap If your home is on a large property the more powerful mikes are best But if your neighbors live only a few feet away you may be better off with a mike having a limited range for two reasons To keep from annoying your neighbor and to keep your personal broadcasts truly personal As you read the following comments about our performance tests bear in mind that many variable factors can materially influence the quality of trans mission The quality of your FM radio can be as important as the quality of the microphone you choose for exam ple Even the physical orientation of the receiving radio can affect the clar ity of reception So inevitably you will have to do some practical experi menting to get the most from your system Our informal range tests were made in the following manner An old man ual darkroom timer was used to pro 43 a WIRELESS MICS The Micro FM from MLI is the smallest unit we have found It features a built in on
261. ransformer is mounted inside its case If you want to use an AC supply a 6 to 9 volt DC unit will work well but it must not be mounted inside the Third Ear s case Construction Construction is easy because you don t need to worry about the layout anything will do A PC board is not absolutely necessary but if you like to give your projects that pro fessional look use the PC patterns pro vided You should test LEDI1 s sensitivity before wiring it into the circuit Bar gain LEDs especially may not be sen sitive enough to be used here Hook your LED in series with a 1000 ohm resistor and connect the combination to a 7 5 VDC source Get the polari ties right If you do not obtain an easily visible red glow try another LED Red LEDs are more sensitive than green or yellow ones so stick with red When wiring duration control R5 make sure you obtain maximum re sistance in the fully clockwise position This will then give you a maximum time delay When building your Third Ear you r ACTIVE ACTIVE 42 r ACTIVE The printed circuit board for The Third Ear is easy to make You can use this tem plate for a photo graphic copy or just duplicate the pattern with a resist pen p Make a three quarter inch diameter hole in the front panel of the cabinet or wherever you want to put the microphone Adjust the sensitivity so that it triggers correctly would be better off with sli
262. rent will flow and which components will it flow through Collector current will flow It will flow through the resistor Ac and the transistor The path of the collector current is shown in the diagram below QUESTIONS 11 List the components through which the collector cur US ec ee Se SCP a a RT 12 What causes the collector current to flow ANSWERS 11 the resistor Rc the transistor and the battery 12 base current Collector current cannot ever flow if 81 fa oe current is not flowing first It is a peculiar property of the transistor that the ratio of collector current to base current is constant The collector current is always much larger than the base current The constant ratio of the two currents is called the current gain of the transistor and it is a number much larger than 1 Current gain is given the symbol 8 called PAN Typi cal value s 8 range from 10 to 300 100 is a good typi cal value from many transistors and we will use this number for convenience in our calculations QUESTIONS 13 What is the ratio of collector current to base current called 14 What is the symbol used for this 15 Which is larger base or collector current 16 Look back at the circuit before question 7 Will cur rent be greater in Rb or in Rc ANSWERS 13 current gain 14 8 15 Collector current is larger 16 The current is greater in Rc since it is th
263. retai price is 279 95 For more information write to Fanon Courier Corporation 990 South Fair Oaks Avenue Pasadena CA 91105 TRS AM SSB BASE This handsome looking AM SSB base station transceiver from TRS is a full function CB with a complete set of con trols The TRS Challenger Mode 1400 has separate S and SWR meters digi tal channel indicator and a built in digi tal clock timer The 1400 also features RF gain control switchable noise blank er adjustable squelch ANL Delta tun ing and tone control According to TRS the Model 1400 puts out 4 watts RMS CIRCLE 79 ON READER SERVICE COUPON on AM and 12 watts PEP on SSB The modulation is limited to 100 percent and spurious and harmonic suppression is 60 dB The manufacturer claims an AM sensitivity of 0 7 uV and an SSB sensitivity of 0 3 uV It operates on 117 VAC Retails for 599 95 For more in formation write to TRS Marketing Inc 137 East Savarona Way Carson CA 90746 CB VHF Marine Antenna Antenna Specialists new ASM 107 dual band VHF CB marine antenna is now in limited production The ASM 107 is a CIRCLE 80 ON READER SERVICE COUPON 17 foot fiber giass whip capable of si multaneous high performance on both VHF 156 163 MHz and CB all 40 channels What makes it possible is an electronic isolation coupler which sep arates the signals and feeds the two transceivers The advantages of the ASM 107 are extra safety and the con venience o
264. rogram memory ENTER means enter channel number into memory or monitor STP means stop the way you exit a computer mode It looks complicated at first glance but a short evening s practice is all it takes to make you a computer programmer The panel Switch BZ CL determines whether the scan stops on a busy or clear channel The CSS switch provides continuous 40 channel scanning with no py This is truly a super unit for the active CBer A CB rig with a touch pad Right Because the Pace 8117 is con trolled by an on board microprocessor meaning micro com puter For more infor mation circle number 64 on the reader serv ice coupon micropracessor they simply come with the computer which provides a user selected 10 channel scan mode a con tinuous scan of all 40 channels without stop a 40 channel scan and latch onto either a busy BZ or clear CLR channel and a programmable monitor that allows you to receive on one chan nel and monitor another on a sampling for one half second every 10 seconds Two front panel switches determine what happens when the computerized scan or monitor finds what you re look Ing for One switch labled BZ and CLR determines whether a scan stops on a busy or clear channel A switch labled CSS provides a continuous 40 channel scan without a stop If the scan stops latches to a channel in the BZ or CLR mode it remains on that chan nel until the user resum
265. s 97 When applications demand analysis of the charac teristic curves of semiconductor devices the B amp K PRECISION Model 501A is the cost effective answer Displays characteristic curves for all semiconduc tor devices on most any scope Non destructive breakdown voltage tests Simulates actual operat ing conditions Internal calibration source Cur rent limiting protects device under test 198 Start testing semiconductors faster now See your local distributor for immediate delivery DYNASCAN CORPORATION 6460 W Cortland Avenue Chicago IL 60635 312 889 9087 In Canada Attas Electronics Ontario e International Sales Empire Exporters inc 270 Newtown Road Piainview Li NY 11803 CIRCLE 22 ON READER SERVICE COUPON ELEMENTARY ELECTRONICS May June 1979 al two ears are the norm The two eared arrangement does more than allow listening to your mother in law and wife at the same time Thanks to some special neural circuitry which among other things performs phase and magnitude comparisons between left and right ear signals a two eared in dividual can quite accurately tell where a sound is coming from You know how marvelously well the present sys tem works but think of the possibilities afforded by a third ear Wait a second now no one is advo cating surgery as a hobby a la Frank enstein The Third Ear in this instance is a versatile electronic sound actu ated control system It can spy on
266. s of data communications telephone based amp others 208 pgs 21548 6 95 NCR Data Processing Concepts Course By NCR Corp Intro to data processing computers amp digital logic Covers input output devices memories control 256 pgs 21547 7 95 Understanding CMOS Integrated Circuits 2nd Ed By R Melen amp H Garland Begins with basic digital ICs covers semiconductor physics CMOS fabrication technology amp design amp advanced CMOS ap plications 144 pgs 21598 5 95 Transistor Transistor Logic 2nd Ed By G Flynn Discusses digital logic amp different types of logic circuits used in the TTL functiona class With block diagrams schematics logic truth tables 288 pgs 271572 6 95 ELEMENTARY ELECTRONICS May June 1979 g Now availa by mail for the first time s ia Eo pam est a r e s k F N ndame sf of H SAVE 10 when you order 3 or more Examine any book s at NO RISK for 15 Days m G s s s u Clip Out Mail Today YES Please send me the book s indi cated below If l m not completely satisfied may return any or all within 15 days of receipt for full credit or refund Add sales tax where 315 epee Dei D 21552 O 21351 O 21447 O 21548 D 21404 O 21536 DJ 21547 DJ 21586 J 21550 O 21598 O 21459 O 21551 D 21572 O have checked 3 or more titles and de ducted my 10 savings Name Please Print Address C
267. s only 7 is high Bass without bulk Despite its small size System Seven delivers rich satistying bass to 50 Hz and sound levels up to 90 dB for ae curate reproduction of anything trom classical to rock music Wiareiie Seren Fhe Rana has a unique equalization net work engineered especially for the speakers And its switchable so you can use full size speakers if vou wish Compact but no compromises You get full size high fidelity features with System Seven magnetic and aux Inputs tape monitor A B speaker switching even 75 and 300 ohm FM in puts U L listed of course and housed in a stunning jet black metal cabinet with blackout dial Receiver is briefcase sized a little taller than a credit card just 3 1 2 high Each speaker is about the size of two average books The price tor all this may be the surprise of your audio life only 239 95 a savings of 39 90 off the each price Audition System Seven Small has zerer been so beautiful Price may vary individual stores and dealers 4 Division of Tandy Corporation Fort Worth Texas 76102
268. said the expansion was made possible by the addition of two dozen half million watt shortwave transmit ters However reliable sources indicate that these high powered monsters really have been on line for a number of years Supposedly the first of the French built Thomson CSF transmitters was heard as far back as mid 1974 One Million Watts And I wouldn t be too surprised to find the Russians are hooking up pairs of these high watt age units in tandem to sock out a mil lion watts per Closer to home though it will be possible to hear Radio Moscow English programs on your favorite hometown AM radio station American stations are being offered the opportunity to broadcast via tape recordings honest to goodness Radio Moscow English programs Gheli A Shakhov editor in chief of Radio Moscow in a letter to U S radio stations offered to provide free tapes of some of the better known to SWLs at least programs and featurettes of good ol R M These include the familiar Moscow Mailbag program the 15 minute show featuring the pudgy and personable Joe Adamov and his answers to listeners letters Another program offered is Vladimir Pozner s views on domestic and foreign policy Moscow Merid ian Other shows known to DXers featuring USSR folkmusic and focuses on Russian science and the arts are also in the free package Though the offering is said to be without cost to the stations Shakov made it clear t
269. same figure find Vo when Rb 100 k9 chapter e Vs 10 V Ae S Tko ands S0 Ae u 5 2 P SELF TEST 8 Repeat question 7 with these values Rb 200 ko The questions below will test your understanding of this chapter Use a separate sheet of paper for your diagrams or calculations Compare your answers with 9 the answers provided following the test 1 Draw the symbols for an NPN and PNP transistor Label the terminals of each 2 In the figure below draw the paths taken by the base and collector currents Vs 10 V Ac 1 ko and 8 90 _ Now use these values Rb 47 ka Vs 10 V Rc 500 ohms and 8 08 T ef ee Now use these values Rb 68 Ae Vs 10 V Rc 820 ohms ande Fone e S r s s Baha 10 Answers to Self Test if your answers do not agree with those given below go back and review the appropriate sections ie 2 3 What causes the collector current to flow san Simply Basic 3 Base current 4 Current gain is the ratio of collector current to base i current It is given the symbol 8 8 Ic Ib Continued from page 71 TOMMY DORSEY BIS BAND MARIE LED ZEPPELIN BLACK DOG 5 Ib Vs 0 7 _ 3 V 0 7 V 23V Bae uA STEVE MILLER BCOK OF DREAMS 10 BB 2k 27kq STEVE MILLER JET AIRLINER 10V Iib gt 45 CCMMAND ARTIST 6 Ib 220 kQ 45 45 UA NAME CF ARTIST STEVE MILLER 7 ALBUM BCOK OF DREAM
270. sary to build twenty different radio and eleetronics tir tuits each guaranteed to operate Our Kits contain tubes tube sockets variable electrolytic mica ceramic and paver dielectric condensers resistors tie strips hardware tubing punched metal chassis Instruction Manuals hook up wire solder selenium rectifiers coils volume controls switches solid state devices ete No Knowledge of Radio Necessary No Additional Parts or Tools Needed Solid State Circuits Vacuum Tube Circuits ages and back amp rounds have successfully used the Edu Kit in more than 79 coun tries of the world The Edu Kit has been carefully designed step by step so that you Cannot make a mistake The Edu Kit allows you to teach yourself at your own rate No instructor is necessary In addition you receive Printed Circuit materials including Printed Circuit chassis Special tube sockets hardware and instructions You also receive a usefui set of tools a professional electric soldering iron and a self powered Dynamic Radio and Electronics Tester The Edu Kit also includes Code Instructions and the Progressive Code Oscillator in addition to F C C Radio Amateur cicense training You will also receive lessons for servicing with the Progressive Signi Tracer and the Progressive Signal Injector a High Fidelity Guide and a Quiz Book You receive Membership in Radio TV Club Fre
271. sembly DO IT YOURSELF amp SAVEI This Sh Wt 38Lbs 9Y0005 68 88 Pr F O B Peabody Ma No C O D s pine Massachusetts Residents add 5 E PHONE DADERS WELCOME 3 Use your Bank Americard Master Charge or American Express Credit Card 10 00 min on all charge orders z B amp F ENTERPRISES 3 Dept E 56 119 Foster Street Peabody MA 01960 Price 888 88 617 531 5774 Viatron System 21 be 495 00 imp hi IBM SELECTRIC BALL PRINTER L amp uUnRPLUS gt FREE JUMBO CATALOG JAM PACKED WITH SURPLUS ELECTRONIC PARTS GADGETS KITS AND MORE CIRCLE READER SERVICE COUPON CIRCLE 5 ON READER SERVICE COUPON HOBBY WORLD CALL TOLL FREE 800 423 5387 CA HI AK 213 886 9200 ICOMPUCRUISE only 165 Navigational compules o mobile use Features cuise control fuel management inp computers umer counter Warm low fuel Compernsates fo pre 92 coments to mem 44 inchons Mounts easily on dash Easy to read bright blue digits With installation in struc tons Cat No 1166 LIFT IT PC DUPLICATING KIT 25 Sg PC patterns Irom mag ty and easily No addiu ofl clerk tequired No camera needed With x 12 sheet of film We slock all refills with step by step instrochons Cat No 1203 IC MASTER Cat No 1292 1979 45 y 20 for 100 10 lot 1 00 10 tor LOO SEND FOR FREE SPRING CATALOG FEATURING FACTOR FRESH PR
272. sion from the British Broadcasting Corporation in London I d never heard a foreign station before and I was thrilled that a fragile thread of energy called a radio wave could span a mighty ocean and link the far off Brit ish Isles with the Silvertone console in our living room Since then using receivers bearing names like Hammarlund Hallicrafters Drake and Realistic I ve heard the BBC countless times But I haven t for gotten the evening nearly thirty years ago when I heard the station for the first time I still listen to the BBC today and not just to recall a pleasant boyhood experience Along with millions of oth er SWL s I listen because in its long broadcasting day the World Service of the BBC offers a tremendous variety of programs received at good strength just THE AGE OF 12 while exploring While the BBC doesn t normally send QSL cards it does have frequent SWL contests These DX certificates and World Radio Club banners are often an SWL s most prized possessions British broadcasting empire about anywhere on the globe where you and your receiver happen to be Empire Service Calling its short wave programs the Empire Service the BBC began broadcasting on high frequency December 19 1932 Six days later on Christmas King George V used the infant medium to address his subjects throughout the world He spoke of radio s power to do good and bring people closer
273. splitter to a crystal diode detector The detected output is filtered and coupled back through the tuned circuit to the amplifier where the signal is now at audio frequencies The audio frequencies are amplified and fed through the signal splitter to the low pass filter and to the headphones As shown in the block diagram and the schematic radio signals are cou pled through Jl and Cl to the tuned circuit of C3 L1 and to the gate of the field effect transistor j FET Q2 C2 places the bottom end of LI and the rotor of C3 at RF ground R3 sup plies the bias for Q2 and C8 is the RF AF bypass capacitor R1 functions as the Q1 gate DC return and audio input load The amplified RF signals from the drain of QI are coupled through C9 to R5 and detector D1 C7 is connected in shunt with the RF out 46 by Charles Green An easy to build one transistor reflex receiver put of QI and is used to adjust the RF gain of the J FET The detected audio signal is fed through the RC filter composed of R4 C5 and C6 to the volume control R2 The audio is then coupled through C4 to the junction of R1 C2 L1 and C3 C2 presents a low impedance to RF but has a high impedance to audio L1 has a high impedance to RF but has a low impedance to audio The two types of signals RF and audio are therefore applied directly to the gate of QI each being amplified therein The amplified audio signal at the drain of Q1 is coupled through
274. ssion pe riod of 1934 to 1937 reflex circuits were used in small home radios When transistors first became popular two transistor radios were manufactured in Japan and sold here for very small prices These transistor circuits employ ed reflex amplifiers usually in a TRF type of receiver with a crystal diode detector One transistor was employed as a reflex RF amplifier and first audio stage and the second transistor was used as the audio power amplifier You can experiment with the reflex circuit by building our simple one Transistor Reflex Receiver project The circuit employs a j FET as a tuned RF amplifier and also as a stage of audio after the signal is detected by a ger manium diode The circuit is laid out breadboard style for easy construction The Reflex Action The reflex circuit is a system in which an amplifying de vice transistor or vacuum tube is made to function at both RF or IF and audio frequencies As commonly used the signal is amplified by the de vice detected and the resultant audio signal fed back into the same device for further amplification Such a circuit has two inputs one for each type of signal frequency and two outputs with filtering necessary to split the two sets of signals Look at the signal flow block dia gram of the one Transistor Reflex Re ceiver project This is a diagram of a typical reflex circuit Signals are am plified at RF frequencies and then fed through a signal
275. t based upon your own experiences It is truly un fortunate that many operators substi tute dollars and cents for common sense and kilowatts for milliwatts when the latter in each case is sufficient to accomplish the task at hand Remem ber the whole world is listening to you Think about it the next time you fire up the rig fers G a F rvD C s r y S PS O MTH O M h by DXers and SWLs is the image Unlike harmonics and other spuri ous signals produced by the transmitter an image is not real it is produced within the receiver itself It causes nov ice SWLs to report stations on err neous frequencies and creates adci tional interference for DXers You can t always cure them but every listener should be able to tell these phonies from the real thing Superheterodyne All images are the result of superheterodying i e the mix ing of two frequencies in a circuit to produce two other frequencies the sum and difference of the two original fre quencies If you mixed WWV s 2500 kHz signal with Voice of America s 6190 kHz Greenville transmission WWYV and VOA would appear on 8690 kHz 6190 plus 2500 and 3690 kHz 6190 minus 2500 All modern radio receivers take advantage of the super heterodyne principle to provide more efficient and less expensive amplification circuits Every receiver contains its own built in mini transmitter known as a local
276. t of money on batteries Radio CIRCLE 39 ON READER SERVICE COUPON the fre quency response of Maxell UDXL is ss d 10 free 6 ft RCA to RCA hook up cords f W Wu F H ZIEL Sir ear mai h cn cr ML 90 Shack sells a similar 4 voltage adaptor for 9 95 The deluxe 120z can of spray head cleaner will clean your tape heads for years to come The handy snorkel in cluded can reach just about any tape head even 8trk heads Radio Shack does not sell a large 120z can but 120z from them costs 6 36 The Radio Shack prices are not list prices but the actual prices you would pay when you walk in the door PE HEAD CLEANER WE WIN TOO Customers like you are very valuable in the form of future business We an ticipate receiving over 6000 orders and 4500 repeat customers from this adver tisement We are betting you will buy our cassettes again and we are putting our money where our mouth is i TRY DAK ML90 FREE We want you to try these high energy cassettes on your own recorder without obligation for 30 days If you aren t 100 satisfied for any reason simply return the tapes and bribes to DAK for a full refund To order your 10 DAK ML90 minute high energy cassettes and receive your 35 21 bribe with your credit card 4 simply call toll free 800 423 2636 in Calif call 213 984 1559 or send your check for 21 90 plus 3 for postage and handling for each group of
277. t the collector Vc and record ed your measurements Let s examine how to deter mine the voltage at the col E lector when measurement isn t feasible This will also i show how the collector volt age can be determined with out measurement Apply these steps to the circuit above 26 Determine Ic 27 Determine the voltage drop across the collector re sistor Rc Call this Vr 28 Subtract Vr from the supply voltage to get the col lector voltage Let us qo throuqh the first step together 26 To find Ic we must first find b AB Ic B x Ib 50 x 0 1 mA 5 mA Now do the next two steps Use a separate sheet of paper for your calculations 27 To find Vr Vr Rc x le 1ko x SmA 5V 28 To find Vc i Ve Vs Vr 10V 5V 5V i Use ice same circuit but use a value 8 75 Again find I QUESTIONS i Ze ke ee ee hcl E k a Y d ori U T A ara W PE p e a 4 cl Ek a ll ee ee h a B Be ANSWERS gg be A 75 Az 75 30 Vr 1 kQ x 7 5 mA 7 5 V 31 Vc 10 V 7 5 V 2 5V Use the same circuit again but with these values Rb 250 kQ and 8 75 Again find QUESTIONS SN ee an ee ee en ee es eT Pu N Ch ORIAN ee a a ee ee pe Ba 34 AC ne oe T Ro o ee ANSWERS f AON Ys A 1 a 32 Ib 250 kO 25 mA lo 78 xs mA 3mA 33 Vr 1ko x 3mA 3V 34 Vc 10V 3V 7V Write down your values for 35 Ib a E MN a at dem Qp A oe L ae oo ao s s r J
278. tables are very sensitive to vibration so try to put your system on something solid A shakey or hollow cabinet can pick up vibrations that will give a turntable fits Try to isolate it from the floor It was with these types of situations in mind that I chose the two units for lab testing in this issue The Realistic STA 2100 is a real earth shaking AM FM receiver that pumpsi out 120 watts and Kenwood s KD 5070 auto matic record player is specifically de signed to minimize the effects of ex ternal shock and vibration Realistic STA 2100 This receiver is conservatively FTC rated at 120 watts we cranked it up to take off power clipping level on the Ae bench it kus k b G g m ki w a i Pa anita lt i a J s L m a m 7 ka per channel RMS into 8 ohms but when went to 135 watts without batting an LED At this power the frequency re sponse is flat 0 1 dB from 20 to 20 000 Hz with distortion THD no higher than 0 12 percent just right for a disco The STA 2100 has plenty of nice features for the audiophile dual phono graph inputs one of which is adjust able for sensitivity inputs for two tape systems and outputs for four speakers There are level adjust controls for bass midband and treble The bass level is switch selectab e for turnover frequen cies of 150 Hz r 300 Hz and the treble turnover frequencies can be selected at 3 000 or 6 000 Hz Its al most like
279. te baby shoes baseballs leaves flowers acorns etc information and instruction sheets GOLD EDGES 7117 3rd Ave Suite 108 Box P Dept EE xM Scoltsdale AZ 85251 602 994 5752 O No flame or fuss pliers or tools A ELEMENTARY ELECTRONICS 92 New from OV SAD ISSUE IT HAS ALL THE EXCITEMENT OF SF ADVENTURE AND ALL THE DRAMA OF STUNNING VISUAL EFFECTS It s here The 3rd issue of ASIMOV S SF ADVENTURE Magazine 112 pages long New Exciting in this Summer 79 edition more great stories such as Roger Zelany s The Last Defender of Camelot Samuel R Delany s The Tale of Gorgik more of Joe and Jack Haldeman Ws Starschool an editorial from Isaac Asimov himself a column by Craig Miller on SF in Hollywood TV and movies stories by talented newcomers AND a fuil color pull out poster Lots of SF adventure and fun Tr ASIMOV S SF ADVENTURE MAGAZINE 380 Lexington Avenue New York NY 10017 J Enclosed is 1 75 plus 45 handling shipping total of 2 20 for the Summer 79 issue 3 of ASIMOV S SF ADVENTURE Magazine Name d please print Address l 3 City Apt No State ae Zip EEMJ 79 Antique Radio Corner Continued from page 74 Hot Tubes This happening brings up several questions to be discussed Num ber one what would a thief do with more than 13 000 radio TV tubes
280. tems Kits and lessons are designed to work together to demonstrate electronic principles and applications The kit building not only shows you how electronic hardware functions but how various circuit designs accomplish different purposes Your lessons guide you through any number of experiments associated with many projects This is the Project Method and it works Step by step you learn how and why digital electronics has become a part of our world and the even bigger role it is sure to play in the future Whether you are looking for training in Consumer Commercial or Industrial electronics NTS offers fourteen courses some basic many advanced in several areas of electronics An all new full color NTS catalog shows you what each course covers ELEMENTARY ELECTRONICS May June 1979 in home study edad o1se SO IUO1I ye ty and every piece of equipment included Send for it today and see for yourself what s really happening in electronics training technology at NTS Find out how much has changed and what new directions the field is taking You ll probably want to be a part of it It s free Just mail the card or coupon Today NO OBLIGATION NO SALESMAN WILL CALL APPROVED FOR VETERAN TRAINING NATIONAL SCHOOLS TECHNICAL TRADE TRAINING SINCE 1905 Resident and Home Study Schools 4000 South Figueroa St Los Angeles Calif 90037 ELEMENTARY ELECTRONICS May June 1979 r gt 8 8 8 B
281. ter Ft Worth TX 76102 You find many other good sources of parts and equipment in the Hobby Mart section of ELEMENTARY ELECTRONICS Check the ads out and write for catalogs Lend a Hand Here s another list of our friends who need your help Lend a hand boys A Lafayette HE 30 receiver operator s manual and schematic diagram George Kopp 3411 Woodbine a Cincinnati OH 45211 A Viking Model 87 reel to reel tape deck needs accompanying electronics Charles D Jennison 48 C checo St Dover NH 03820 A Hallicrafters S 40A receiver needs Operator s manual and service equipment J O Bois 407 Sumner St Santa Cruz CA 95062 m ELEMENTARY ELECTRONICS May June 1979 Solderless saves time like you wouldn t believe Our Proto Board solderiess breadboards put every thing you need to get your circuit uo and running on an aluminum backplane that lets you work at frequencies from DC to half a Giga Thats why we ve become the Hertz Three Proto Board models easiest to find solderless bread feature built in regulated power boards in the world available at supplies and one of them sa more stores than anybody else in build it yourself kit the business Because people whc CSC solderless breadboards save KNOW solderless best insist on CSC energy too Especially yours Because Save time and energy Get a circuit building becomes a simpe head star with CSC plug and chug process straigt from an idea to a w
282. therwise seems suitable for use in areas where a limited range is desired The sound quality seemed a bit more ragged than that obtained with the AMC mike which has the benefit of a metal case for shielding to minimize body capacitance effects Super Sens FM 2 Mike Kit Ramsey Electronics 4 95 requires soldering about 16 components including a short 5 inch to 10 inch antenna wire to a PC board measuring inch by 1 inches There are no identifying mark Ramsey Electronics FM 2 Wireless Kit sells for 4 95 You supply mike and battery Circle 77 on Reader Service Coupon ings on the PC board but a clear dia gram good parts identification list and a schematic of the circuit make the as sembly easy It should be noted that the kit does not include a microphone element battery connector or a 9 volt battery You must find these locally The manufacturer states that you can use a crystal ceramic or dynamic mi crophonc The crystal type is the most sensitive but the dynamic type offers better fidelity Its claimed that the mike works with a power supply of 3 to 9 volts the higher voltage being preferable You are cautioned that the antenna affccts the transmitter frequen cy therefore close movement next to it should be avoided The main problem encountered with this wireless kit concerned difficulty of tuning it to the desired FM frequency mainly because body capacitance effects were very pronounced Getting a han
283. tifiers test equipment You will learn and Practice Code using the Progressive Code Oscillator You will learn and practice trouble shooting using the Progressive Signal Tracer Progressive Signal Injector Pro ressive Dynamic Radio amp Electronics Tester Square Wave Generator and the accompany ng instructional materiai r 2 You will receive training for the Novice Technician and General Classes of F C C Radio Amateur Licenses You will build Receiver Transmitter Square Wave Generator Code Oscillator Signal Tracer and Signal Injector circuits and learn how to operate them You will receive an excellent background for television Hi Fi and Electronics z Absolutely no previous knowledge of radio or science is required The Edu Kit is the product of many years of teaching and engineering experience The Edu Kit will provide you with a basic education in Electronics and Radio worth many times the low Price you pay The Signal Tracer alone is worth more than the price of the kit THE KIT FOR EVERYONE You do not need the slightest background In radio or Science Whether you are inter ested in Radio amp Electronics because you want an interesting hobby a well payin business or a job witb a future you will fin the Edu Kit a worth while investment Many thousands of individuals of all PROGRESSIVE TEACHING METHOD The Progressive Radio Edu Kit is the foremost educational radio kit in the
284. tions or data for the CPU The numbers of the mailboxes are the mem ory addresses and it is to these addresses that the CPU refers as it steps through a program For instance when the CPU looks at an address it may find an instruction telling it to go to the next address and read the contents of that location into one of its registers CPU registers are special memory locations inside the CPU that are used for temporarily storing and manipulating data Because of its function this type of memory is often referred to as scratchpad memory by Tom Williams Figure 1 The important internal STRUCTION components of the 8080 central process ing unit CPU are shown in this block diagram The data is transfered along the wide lines according to the instruction in the instruction register The clock keeps it all in perfect timing Going to the third address in line the CPU may find a similar instruction which tells it to take the contents of the fourth location and store them in an other CPU register At this point the CPU has two different numbers stored in two of its internal registers The next instruction the central processor sees may be a command to add these two numbers together that is to add the contents of one register to the contents of another The final instruc tion might then tell the CPU to take this result and store it in another speci fied location out in computer memory or to Output it
285. tn our program It tells the computer to put the following number here the num ber 5 into the B register The next in Struction similarly tells it to put the contents of the next memory location into the A register At this point in the program the computer registers look like figure 2 Note that the program counter contains the address of the next instruction to be put into the in struction register That instruction is the ADD B in struction that tells the CPU to add the contents of register B to the contents of register A The result will be the new contents of register A but the data in register B will not be destroyed Answers The question now is what to do with the answer In our case we have chosen to store it in a location in Continued on page 87 ELEMENTARY ELECTRONICS May June 1979 amp IN ELECTRICITY One of the keys to hobby construction fun is a firm understanding of transistor function and operation This article will tell you all you need to know to use transistors in your lat est brainstorm The easy learning format makes understanding transistors a snap even if you ve had trouble with them before _ 7 This article is based on material appearing in ELECTRONICS A Selt Teaching Guide by Harry Kybett John Wiley amp Sons Inc Publishers INTRODUCTION TO THE TRANSISTOR sing transistors in your projects is easy once i you understand how they work This article
286. together A service in Arabic was begun in 1938 to counter Mussolini s anti British broadcasts to the Middle East Other foreign language broadcasts soon fol lowed World War II gave the BBC an op portunity to earn a reputation for im peccable accuracy and thoroughness in news coverage A reputation it still en joys today Citizens of occupied coun tries learned they could trust the sta tion because it always told the truth no matter who the truth might hurt England s setbacks and defeats were reported as faithfully as her triumphs and victories By 1945 almost everyone in Europe believed unquestioningly in BBC news casts On D day when General Eisen hower used these programs to instruct French civilians thousands of people obeyed without hesitation Today the BBC External Services em ply 110 journalists working in shifts to process the more than one million words a day that pour into the news room in London s Bush House This flood is whittled down to fill 250 sepa rate news programs in the 39 languages the broadcaster currently uses The English language around the world around the clock World Ser vice includes seventeen nine minute bul letins of world news daily Also heard are five minute summaries of British 48 ELEMENTARY ELECTRONICS May June 1979 The main console in the control room in the BBC External Services headquarters The BBC multilingual system is highly organized news call
287. two diodes two transistors and one IC It has FCC type approval Frequency deviation is 100 kHz MHz and field strength is put at 50 uV m at 50 feet The manufacturer specifies a range of up to 100 feet indoors and 300 feet outdoors Battery life is said to be from 60 to 80 hours It can be tuned any where in the 88 to 108 MHz FM band Tuning to 103 MHz seemed to pro duce better results than at 108 MHz By turning the receiver volume to about halfway to maximum the transmitted noise signal could be heard anywhere inside the house By turning the radio volume to maximum reception could be extended to reach a short distance outside the house about 35 feet from the mike The microphone was judged to have a somewhat more limited range than the feisty little Micro FM already discussed On other drawbacks is that Formula International s TECT model WEM 16 is powered by a pen lite battery and features an omni directional electret condenser microphone element Cost is 16 50 Circle 75 on Reader Service the lack of an on off switch necessi tates physical removal of the battery when the mike is not being used None theless this mike was judged to be a good buy provided these limitations can be accepted and a preferred mike if your home is close to neighbors and you need a limited range to ensure privacy of your in house broadcasting TECT FM Wireless Microphone Model WEM 16 Formula Interna tional 16 50 is in a di
288. type of image al ways shows up 910 kHz two times the 455 kHz IF below the real frequency Therefore your local oscillator and VOA s 6190 signal can produce a 5280 kHz image while WWV s 2500 kHz transmission might even show up at 1590 kHz on the standard AM band AnotFer Kind Of Heterodyne So far the kind of heterodyning process we ve talked about has involved only radio frequencies But there are also audio heterodynes If you are tuned to BBC Ascension Island on 6005 kHz there may be nterference from Radio Reloj de Costa Rica on 6006 kHz No one need a pocket calculator to tell them that the difference between these two frequencies is 1 kHz 1000 Hz well within the audio range When this not so super heterodyne reaches the re ceiver s audio circuit it will be amplified and emerge from your speaker or head phones as a very annoying whistle To distinguish it from other forms of the heterodyning process the audio hetero dyne is usually referred to simply as a het Just as real interference can cause a T 5 ee a Nu gary lt z 7 a LE TETIT 7 Inn oa ro 63 jan ate us caused by that image and yes _ a IMAGES het so can Image interference but there Is one important difference When the jlocal oscillator produces interference Ga the frequency to which you re tuned by mixing with a strong station on an jother fre
289. ve at a starting ad dress specified by the programmer The kind of machine programming we have discussed in this article is im portant to programmers wishing to write especially efficient or special pur pose programs For the rest of us it Is perhaps interesting to realize that every time a BASIC program says A 7 2 something like that described above takes place in the machine eh qatu million cycles per second ff Signal Snare Continued from page 47 tween the drain of Q1 and ground The station signal should diminsh This in dicates that the RF reflex portion of the circuit is operating correctly The capacitor shunts the RF to ground but does not affect the aydio amplification as it has a high impedance to the audio frequencies Check the audio amplifier portion of the reflex circuit by tuning in a sta tion and then removing the headphones from J2 Temporarily connect a 100 ohm 2 watt resistor in place of the headphones to J2 Connect the head phones with a pair of clip leads across the output of D1 across C6 and compare the signal level with the pre vious level at J2 The level at DI should be lower than that of J2 to verify that the audio is being amplified by QI E Images Continued from page 64 comes time to upgrade your present equipment the first thing to consider is dual conversion With this system two different IFs are used A shortwave signal might for exa
290. velop ment of solid state at the hobby level I ithink you ll find the next five years to be more revolutionary than the first 15 years J Watta Setup gt i 14k I m enclosing a diagram of my DXing antenna layout Can you give me your opinion of the antenna system I use A E Milton FL Terrific You should be able to hear Castro snore I do believe that the 25 foot length is not needed I suggest that you should be able to switch out the dif ea ova te PRET 60 FEET ANTENNA LEAD IN CONNECTS HERE ferent fees of the antenna to toe background noise while Zeroing in on weak signals i You ll Laugh Yourself to Death I get an electric tickle from the metal cabinet of my receiver Is this safe J F Cleveland TN t 4 Pd say No to that But check it your self to be absoultely sure Use an AC volt meter having 5000 ohms volt or more sen sitivity in the following manner Connect a 1500 ohm 10 watt resistor paralleled by _a 15 aF disc capacitor between a known good earth ground water pipe conduit etc and the exposed metal parts on the receiver One at a time Do this with the receiver plugged into an AC outlet and the receiver turned on Measure the AC volt age across the combination 1500 ohm re sistor and 15 yF capacitor Reverse the AC plug and repeat the voltage measure ments for each exposed metalic part For receivers manufactured after Ja
291. will give you the basics of modern transistor theory enabling you to use these tiny dynamos in your construction projects THE TRANSISTOR AS A SWITCH The transistor is undoubtedly the most important mod ern electronic component It has made great and pro found changes in electronics and in our daily lives since its discovery in 1948 In this chapter the transistor will be introduced as an electronic component which acts similarly to a simple mechanical switch since it is actually used as a switch in much modern electronic equipment The transistor can be made to conduct or not conduct and electric current which is exactly what a mechani cal switch does An experiment in this chapter wil help you to build a simple one transistor switching circuit This circuit can be easily set up on a home workbench and it will enhance your learning if you obtain the few compo nents required and actually perform the de of building and operating the circuit From this basic idea we will progress to PAN cir cuits which use several transistors to accomplish the same end This affords an easy introduction to why the transistor is used and to how it is used in computers and other modern circuits When you complete this chapter you will be able to e describe the basic construction of a transistor specify what transistor switching action is e differentiate between the two most common types of transistors e tell which currents flow
292. within the IC and the oscillator signal 1s coupled to the amplifier segment of the IC The amplified 6 000 Hz signal is then fed to an LED which indicates the low fluid condition Construction The circuit can be as sembled quickly and easily on solderless breadboard stock We used Continental Specialties Corp s Experimenter 350 Component layout is not critical but you can use the layout shown in the photograph if you re not feeling terribly creative The probe assembly in our model was made by drilling three holes in a triangular pattern in a large rubber stopper After doing this insert the metal probes we used knitting needles Measure the diameter of the narrow end of the stopper and then cut a hole in the top of the fluid reservoir just slightly larger than the stopper s narrowest diameter thus allowing a snug fit Solder a wire to each probe and connect them to the appropriate pins on the IC Do not cement the probes into position on the stopper yet because you still have to calibrate Calibration and Operation The long est probe which connects to a ground anywhere in the engine compartment that s handy should be pushed down through the stopper so that it s just touching the bottom of the reservoir The refill probe may be inserted to any length depending upon how much margin you wish to have between the first and last warnings Remember water varies from area to area and the type of solvent
293. y I received this sage counsel from a more experi enced researcher A good scientist can do good work anywhere even in a garage And perhaps even the reverse is true today A mediocre scientist not approaching being a genius can succeed in a glamorous corporate re search environment Greenfield Village amp Henry Ford Museum Aayay ANI 6666 06009 9105 9109 OCOINSISSaSTV Sle AVIY 0009 EZS 019E gss SISCIOIAVLIFASCSIIAVLISY LINIHd Q UQS 2 E sp u emoy Jed ino 10 w 3s s y 3Zr jguosi od 0 p urpotu Ajisea aq ued umidoid y L CINVN aLs 0 p sn u q osje SABY SOUT JUdWA eIS dp n wez O1d ay jnoYysno1y pasn u q sey Ju u 348 s Jo d Sulaes 33Aq SIUL I Z NAHL N D AT Peel 0 Justa BYS Su almbal jystw Jajndwos mog 7 N Al Spesr uawas ay O OP oul ut ajdwexs 10 4 Wwajshs ino 10 palo HE8J SI N3H 4 puewwods oog IJguorrpuo5 OISVq ewuswepuny au UIE 1952 ew Wa sAs JaJNdwod U33 JIP e uo Weidold si azn noA JI SSOZ OSOZ SOUT 3S y s p OY uo p io s aLy 1 US20p II uonguuioJuir jund o Sunduu ye Aq s eds yuejq UHA Jy LuoA 1 sey Y yey uonewozur tj jndino Ajuo Im J lnduuo3 y uni weigoid e uO sy8nolui pesr say 1SIU y UO MOHOJ 0 HnOUJDp SI y Ss AX ASI 0109 N SINSI THTU Aly AVIY BERS wINOS fC 90 BVLIAWNETY CBI AVLIE ISTLYV LNIUd AZAS l AWOLSAY BOBS AW
294. you and your loved ones may manage to avoid serious injury your car is likely to be suited for use as nothing more than junkyard scenery The Principle To help you avoid these unpleasant consequences we sug gest you build the Space Cushion Timer This device works on the two second rule The rule simply says that if a two second interval is kept between ELEMENTARY ELECTRONICS May June 1979 Cushion Timer This tailgating gauge helps you to keep your distance an by Thomas R Fox w A k en x tu m i s 125 tei CE r cars at all speeds ample braking dis tance will be provided for safe stops In practice you would fix a landmark at the side of the road such as a light pole When the car in front of yours passes the pole two seconds should elapse before your car reaches that same spot With our timer you merely trip the touch plate and 2 1 seconds la ter a pleasant tone sounds If you re at the landmark then you are a safe dis 12 VDC GROUND sas The components all mount on the side opposite the foil pattern Be sure to double check the polarities of electrolytic capacitors 51 2 2 SPACE TIMER tance behind If not then adjust your speed accordingly Construction Best results will be ob tained by constructing the timer on a PC board We have provided a tem plate which you can use for etching your own board All components ex cept for the spe
295. your friends mind the phone babysit thwart would be burglars and much more Later on the Third Ear s appli cations will be explored in detail but first let s examine its circuit The Circuit The heart better yet the eardrum of the Third Ear is a tiny module the ETCO S 210U sound trig ger This little device originally formed the nervous system of an electronic turtle The species is now extinct un fortunately but its innards are avail able as a great surplus bargain As you can see from the schematic the S 210U contains a crystal microphone a transistor amplifier and an SCR The module s black lead goes to the minus side of a battery while the red and green leads will be shorted together in this application The shorted leads con nect to one side of a low resistance load like a relay and the opposite end of the load goes to battery positive Sound picked up by the microphone is amplified by the transistor and fed to the SCR s gate If the sound is suf ficiently loud the SCR latches in a conducting state thus drawing a rela tively large current through the con nected load Power must be removed in order to turn off the device again A more Versatile system should op erate in either of two modes latch or pulse After the first triggering impulse of sound the latch mode system re mains active A pulse mode system on the other hand remains active only for some pre determined time interval

elementary MAY -JUNE 1979

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