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48SX Scientific Calculator

1. 6 3 PETI ad P4130 1500 1 225 L 63 15000 P6312 P62 P4133 IB IK 225 44 6 P6313 P4132 2200 1 293 z P6311 a Paixa 2700 IK 293 J P6315 PS P4134 3300 IK 2 93 47 P6316 P6 4 M pars 390 1K 436 aa x P5317 F P4135 47OD K 5 36 No Description Pho 16 1000 1 000 P6318 P4137 S600 TK 536 NU 0 560 4 P4133 6800 Ik 8 44 90 P4139 B200 K 844 94 P4140 1000Q iK B4 94 Path 10000 50 86 55 P4162 2200n 40 g4 P4163 17000 450 1 01 j in pus a B paalt 1000 50 Bo bt H682 6800 50 E P4437 1500 x B6 5 CARBON FILM RESISTORS Pa 1000 100 GB P4433 2200 50 86 Available in 1 8 1 4 amp 1 2 Ware f r 1500 B P443A 3300 50 B6 4 1 P4203 2200 S P4435 4700 50 86 3i 26330 P6225 4205 3300 73 P4436 6800 50 94 6 4 6331 P6226 P4206 4700 JO P443 10000 50 101 100 P6332 P6227 P4209 6800 100 P4438 1500 50 6 220 P6333 P6228 D Ot S6 P4439 22000 50 6 pat Hes 33 BLU Ll P4303 022 075 64 Peay 33000 50 E w TU P6336 PE231 4 PAIS 033 025 64 P4434 47000 50 200 P6337 P6232 67 3 300 P6338 P6233 e well 3 t6 r00 P6339 P6234 p Ww G 54 500 1 0 Watt Rexistor Assortments 16 6 800 P6340 i P6235 31 a 68 500 RS112 9 90 10 000 P6341 03 t8 82 500 1 18 P6342 2 22 KX 79 100 500 25 P6343 ool P440 27 500 13 120 500 25 22 P6344 46 P5436 3 00 c 150 S0 w X P6345 23 623 Paap 3 500 c 180 500 25447 P6346 34 P6238 47 500 220 5
2. M PLOT THE EQUATION ROOT 3 311737691949 SLOPE FOUND Fi ENTKRM 2 3 4110890265 Fig 3 Some of the things you can do with the HP 48SX top to bottom plot an equation zoom in on points of interest in the plot obtain values for the roots of the equation find the slope of the equation at any point and find the point where a local mini mum or maximum occurs program and press Enter The pro gramming language is full featured in that you can include such things as variables loops conditions and tests in your programs To send data from one HP 48SX to another you must first line up the computers back to back along an ar row marked on the face of the calcu lator Then you press the orange ar row and 1 O keys This brings up an I O menu This menu contains all commands needed to send data along the IR link or through the serial port The HP 48SX uses Kermit protocol to transfer data HP 48SX Features The wealth of features of the HP 48SX reminds me of the sign you of ten see in stores If you don t see it ask for it For the HP 48SX you could say If you don t know if it can perform a mathematical operation check the manual You ll probably find the feature you are looking for If you want to operate in the graphics mode the HP 485X can zoom in on a portion of a graph and automatically find roots slopes
3. RSIX R 1097 29 95 B No ipfh V 10 5o 35 P4000 10 21 POE D 95 N RS2X 29 95 P4002 5 500 64 Pat 00 500 68 v pana B 500 64 Pal 500 68 1 6B6 xon HC tA zi 79 95 W Ps 22 500 64 P4103 180 500 68 M ooo AM c E 00 PaO 27 500 6A P4104 220 500 68 M i oso UD HO fe n 29958 P25 3 50 64 P4105 270 500 68 M 3 jose X007 ar X5 oum tis 39 500 6 amp 4 P4106 330 500 68 a h 17 500 64 Pa oso E82 090 HC t LA 13 50 329 95 56 500 amp 4 P4 470 500 79 B 5 000 X05 HC 18 162 13 50 ae BOC bf 9 Im 5 0688 X052 HC f 162 1350 yia Lue 560 500 79 5 1850 X0 3 18 1 62 13 50 PANASONIC SU SERIES S2500 IJP ouo Boro x073 162 1350 Miniature Aluminum Electrolytic Capacitors 1500 25 ag r 1000 500 94 000 xs e 13 Axial Load Radial Lead 7 a A eee 585 XC74 HC 1B 162 1350 WY Cap Dyr Key Prce Digi Key Price ay Pee a 1 74 i X rn K S A 000 KOSS HC 18 1 62 13 50 IVDC GFI Part No 1 Part No Pe E ne aay Eee on B 9 2160 x07 HC 162 1350 634 25 P3414 3000 25 1 3 e401 180 1K 20 fe 19 000 XQ HC 18 62 12 50 6 P6302 26 16 P4148 15000 25 P4 220 1K 78 11 0592 x078 1a 38 16 50 6 P6303 IS P6202 M patas 22000 25 teal 270 1K ze fy 2 000 X058 18 1 G2 50 6 3 330 P6304 42 P6203 22 Pese 33000 25 126 62122 Boi 199 M 7 000 X05 HC 18 t 62 50 6 3 470 P6305 46 P6204 23 pais 1000 50 1 09 P2123 390 1k 99 M 6 000 x HC 18 1 62 30 6 3 000 P6306 54 P6205 38 MO parsi 0500 50 H P4128 170
4. Fig 3 Schematic details of the Programmer s A LED indicator B Serial Port and C Parallel Port circuits via J making certain that the power source is properly polarized With power applied to the project touch the hot probe of the meter to each of the V socket pins indi cated for U through U 21inthe table accompanying Fig 4 A n all cases you should obtain a reading of ap proximately 5 volts If you fail to obtain the proper reading at any one or more points in the circuit power down the Pro grammer and rectify the problem Check to make sure that all compo nents are in the correct locations and that all are properly oriented and based Check to make sure that all components are soldered into place Solder any connection you might have missed and reflow the solder on any suspicious connection If you lo Say You Saw It In Modern Electronics cate any solder bridges particularly between the closely spaced pads for the IC sockets clear it with desolder ing braid or a vacuum type desolder ing tool Do not proceed until you have rectified the problem Once you are certain that the proj ect is properly wired plug the 78S40 into the U2 socket Make certain that the chip is properly oriented and that no pins overhang the socket or fold under between IC and socket This applies for a IC installations Re apply 5 volts dc to the project With the common lead of the me ter still co
5. tation and advanced diagnostic software NEW HARDWARE CPU s IBM Apple Compas and others Printers Okidata Epson HP Lasers and others at huge discounts PARTS amp BOARD REPAIR Installation and Repair FINANCING Available for qualified businesses OVER 125 DEALERS WORLDWIDE Find out why more and more electronic professionals are adding computer repair to Single source for parts and board repair their businesses or starting their own com 24 hour express turnaround puter repair businesses Call Tech Serv at 212 967 1865 now tecncerv SERVICING THE WORLD OF MICROS 253 West 28th Street New York NY 10001 CIRCLE NO 166 ON FREE INFORMATION CARD 1989 Tech Serv Corp 77 Classified Commercial Rates 1 per word 15 word minimum 15 00 prepaid Word count includes name and address ZIP code and abbreviation each count as one word P O Box number and telephone number count as two words each Indicate free cate gory heading Computers Communications Electronics Video or Miscellaneous A special heading is available for a 6 surcharge First word only is set boldface caps at no charge Add 20 for additional boldface words Non Commercial Rates FREE to subscribers as space permits maximum 15 words A recent MODERN ELECTRONICS mailing label must accompany ad All advertisers with P O Box addresses must supply permanent address and telephone number Copy is subject to publisher approval
6. Mailing Information Copy must be received by the publisher by the 25th of the third month preceding the cover date Send Advertising material with check or money order or credit card information Visa or MasterCard only with number and expiration date to MODERN ELECTRONICS Classified Department 76 N Broadway Hicksville NY 11801 Ee S oo PICKS UP A WHISPER 50 FEET AWAY The modei WAT 50 miniature FM tranmitter uses a 4 stage circuit NOT to be confused with a simple wire less microphone Simply snap the unit on top of a 9V battery and you can hear every sound in an entire house up to 1 miie away Use with any FM radio Tunes to any frequency from 70mhz 130mhz Easy to assemble kit includes ali parts and Instructions Only 29 96 tax Incl him p The WIRELESS TELEPHONE TRANSMITTER model WTT 20 Is only about the size of a dime yet transmits both sides of a telephone conversation to any FM radio with crystal clarity Completely automatic Uses power from the telephone line itself never needs a battery Up to mile range Tunes from 70mhz 130mhz Easy to assemble kit Includes all parts and instructions On ly 29 98 tax Incl Call or send MO VISA MC for immediate dellvery Singie kit orders Include 1 50 S amp H FREE SHIPPING on orders of 2 or more Ail orders shipped by U S Maii COD add 4 00 Personal checks aliow 21 days DECO INDUSTRIES BOX 607 BEDFORD HILLS NY 10507 914 232 3878 CIRCLE NO 1
7. May 1990 MODERN ELECTRONICS 59 finite fall time to cool below the temper ature where it emits visible light when the current is removed These delays are sometimes known as thermal lag Thermal lag is directly related to the physical dimensions and mass of a lamp s filament Because of the tiny size of its fil ament the light from a flashlight appears toswitch on and off instantaneously Au tomobile headlights have very large fila ments and require a noticeable time to achieve full brilliance when switched on and to be extinguished when switched off The same applies to filament lamps used on tall antenna towers The xenon strobe lamps used on some towers flash off and on almost instantaneously The filament lamps used to mark most towers seem to switch off and on as if they were powered by an undulating sine wave Relay Lamp Flashers A relay is physically larger than a semi conductor Switch such as a silicon con trolled rectifier SCR or power MOS FET Also a relay requires a drive cur rent that a semiconductor switch does not Nevertheless relays are exceptional ly reliable and provide a very low on re sistance Therefore they are well suited for use in lamp flashing applications There are many ways to switch a lamp off and on by means of a relay Circuits made from 555 timer chips are particular ly popular since flash rate and duration is easily varied Figure 1 shows a super simple relay lamp fla
8. One major benefit of this is that while you can use Series II and earlier font cartridges in the LaserJet III s cartridge slots the new font cartridges and down load softfonts being produced for the IIP and LaserJet III printers contain only portrait fonts Because the landscape lE ees SSS Sa eee ker OE ee ee May 1990 MODERN ELECTRONICS 67 Say You Saw It In Modern Electronics HAM RADIO IS FUN Its even more fun for begin ners now that they can oper ate voice and link computers just as soon as they obtain their Novice class license You can talk to hams all over the world when conditions per mit then switch to a repeater for local coverage perhaps usingatransceiver in your car or handheld unit Your passport to ham radio adventure s TUNE IN THE WORLD WITH HAM RADIO The book tells what you need to know in order to pass your Novice exam Two cassettes teach the code quickly and easily Enclosed is my check or money order for 19 00 plus 3 50 for shipping and handl ing or charge my VISA MasterCard Am Express Signature Acct No Good from Name Address Expires City THE AMERICAN RADIO RELAY LEAGUE 225 MAIN ST NEWINGTON CT 06171 CIRCLE NO 155 ON FREE INFORMATION CARD PC CAPERS fonts have been eliminated these collec tions generally include more fonts for the same or lower price On the fly font scaling and rotation features are derived from the AGFA Comp
9. Engineers celebrate their profession with a whole week this year February 18 24 with National Engineers Week Activities revolve around Discover E a nationwide program that provides hands on engineering experiences to students through schools museums and libraries The Week is co sponsored by the Institute of Electrical and Electronic Engineers IEEE association FCC PROPOSES CODELESS HAM LICENSE With PR Docket 90 55 the Commission proposed to amend its rules by establishing a codeless amateur operator license the Communicator Class The FCC proposal also included modifying the licensing structure to Communicator General Advanced and Amateur Extra Classes Present Technician and Novice licenses would be grand fathered indefinitely but they will no longer be issued if the Cited proposal becomes official But under the new structure you d need a General or grand fathered Technician Class license to communicate on popular 2 and 6 meter VHF bands where operators can reach a telephone number with a wireless portable or mobile rig and a relay club membership PERSONAL COMPUTER TIDBITS Maxell has introduced pre formatted disks in the industry s four most popular formats Ungar has a line of electrostatic dissipating ESD office and desk accessories including various letter trays desktop accessories organizers etc The black matte finish products protect ESD sensitive parts with Class 1 2 and 3 sensitivity classifications 0
10. descriptions orders E Se E Ec 78 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics 3400 TTL Tissue Pert Pre A 3N 100 J44 N ADIN N 102N 4 E Bg 03 i 1153654 403N 36 ipe A05 4 B uon J58AN 407N ai N 408m at 4N 409 T TLS SN sag 0 AN N z gt AISE A iud ied 4 i N gt Part 3 3t 3 N 02 N IN L iN 140N 4B N 147N JN SO9N 4456AN S 108 447AN IN ON 4 5N 451N N 45 3h 1 1822N j 14S 30N dn HSIN 173N a a 174M z PISA t oq 74S64N 1 4S6 185N uu LOB 8 eS 4895 Mr 45113 74308 45114N 493AN JN no 4N DON 1358 N 138N 1123N ibus 1125N pice 481518 1 32N 4S JN 1145N 1 7 IN 1148N 745158N A amp 4S16IN 4 4S153N 4153N 45 174N 4154N 4SV75N A155N t T 4157N i 3 d 15 AN JAN 74164N IN A166N 3173N m i 4524 IN 4524 3N 41 80N 90 45744N AIDIN 74 8 7N 4 N 7410AN 4 45253N 11852N P 139918 K 4 N 1 4193N 31379 4S288N 32518 453 N 3J65N 1 37 48 3J6 M 1538 7N 4 6i 4547 2N 5 4 JN 54 4547 4N ta amp 4 a IN 5492 4 N 549 1N 45940N 54941N 41594 th Pari i ICO A h 4 N J COEN N CION iN ac VAN 11510 iC N 118 ON 3512N i 4 514N i SS 058 CARN 1 5208 IN 4l 4 iN 115268 BN 4 N T N SN 4 N N 4 N N 3 N 5820 4CS3N IN C35N TN JAN N AAN N 445746 1548 10S 78N N 4LS8JAN N 1158
11. even a business of programs in your own making computers do BASIC Pascal anything you want them to do The only programming course that includes a powerful computer system and software you keep Unlike any other school NRI gives you hands on programming experience with a powerful IBM compatible West Coast com puter system including 2400 ADDRESS Only NRI gives you an IBM compatible computer with modem l 640K RAM disk drive monitor and software BASIC Pascal C and COBOL all yours to keep CITY STATE ZIP Accredited by the National Home Study Council Bem ees ee u aX ee ee es ee ee A X ee A ee A C and COBOL Then rounding out your training you use your modem to talk to your instructor meet other NRI students even download pro grams through NRI s exclusive pro grammers network PRONET Your career in computer programming begins with your FREE catalog from NRI For all the details about NRI s at home training in Computer Programming send the coupon today Soon you ll receive NRI s fascinating information packed full color catalog Open it up and you ll find vivid descriptions of every aspect of your NRI training You ll see the computer system included in your course up close in a special poster sized foldout section And best of all you ll find out how your NRI training will make it easy for you to build that high paying career
12. No matter what your background NRI gives you everything you need to succeed in programming today s top growth computer career field You need no previous experience to build a successful programming career with NRI training Indeed vour NRI lessons start by walking you step by step through the fundamentals giving you an expert understanding of the programming design techniques used every day by successful micro and mainframe programmers And then the fun really begins RICK BRUSH NRI PROGRAMMER ANALYST Start with training that gives you hands on programming experience at home and at your own pace Training that begins with BASIC then continues with Pascal C and COBOL today s hottest computer languages Training that even includes a powerful IBM compatible computer modem and program ming software you keep Start with real world training The kind of training only NRI provides Now with NRI s new at home training in Computer Programming you can be one of today s highly paid creative team of computer wizards who give computers the power to carry out an astonishing range of business profes sional and personal applications Now With your personal NRI instructor on call and ready to help you use your computer and software to actually design code run with NRI you can be a computer M debug and programmer ready to build a high TOME document paying career
13. TEST YOUR BLOOD ALCOHOL CONTENT BEFORE DRIVING 2 5 00 ppd R J CROW_EY P O BOX 1087 WILLIAMS VILLE NY 14231 ATTRACTIVE ORIENTAL LADIES seek ing correspondence marriage Professional introductions since 1984 Asian Experience Box 1214TZ Novato CA 94948 415 897 2742 MAKE 50 hr working evenings or weekends in your own electronics business Send for free facts MJOI INDUSTRY Box 531 Bronx NY 10461 2l ore Qe SURVEILLANCE Privacy control Debug g cS E UN grav ging Protection kits assembled Large new ases eco e wre catalog 5 00 Tri Tron 2209F Lapalco Har vey LA 70058 SURVEILLANCE COUNTERSURVEIL LANCE Guaranteed lowest prices Unbeliev able Detectors Jammers Transmitters Phone Security Cameras Personal Protec tion Books More Huge catalog 5 00 re fundable PROTECTOR PO Box 520294 C R Salt Lake City UT 84152 MET Xv p FREE Subscriptions to over 200 major com det ouo amp a Beck yee puter and business magazines guaranteed Write for free information SEABIRD 4J Mi litia Drive Lexington MA 02173 a P O Box 567 AL Nuys C a 91408 0 6 HOUR AUTO INSTRUMENT SHUT OFF TIMER ENCLOSURES f M H Rhodes Inc Molded ABS instrument Mark Times 90007 Wall box 4 enclosures Matching e timer fits standard 3 deep front and rear panels os ws wall box Rated 20 amps Integrated PC board 3 125 Vac Turn knob to desired time n
14. When the output of the 555 in this circuit is low no bias voltage is applied to the base emitter junction of thetransistor This keeps the tran sistor in cutoff But when the output of the 555 is high the transistor is biased into saturation causing it to turn on hard The cold end of the load connected to the collector of Q1 is thereby grounded and current flows The value of the Q base resis tor is dependent upon the load cur rent and the beta of the transistor It can be found experimentally A pnp transistor is used in the same manner in Fig 8 B With the pnp transistor the base must be less posi tive than the emitter so that this cir cuit turns on when the output of the 555 is id When the output is high K1 Current Sink D1 1N4148 1N4148 1N4148 R2 Fig 8 Details of use of A npn and B pnp transistor switches to increase cur rent handling capability of a 555 the emitter and baseare at closetothe same potential so no action occurs Even greater currents can be ac commodated if you use a relay as the load for the 555 output as in Fig 9 In addition the relay makes it possi ble to use the 555 in a low voltage dc circuit with other electronics to con trol a high voltage load circuit Select a relay with a coil rating of 18 volts dc or less 5 6 and 12 volts are common Match that voltage to the V used to power the 555 For example if you are powering the 555 from a 12 volt dc so
15. and comes with a 9 volt battery and a pair of test leads 49 CIRCLE NO 127 ON FREE INFORMATION CARD Programmable Scanner New from Cobra Electronics the Model SR 901 desktop scanner offers programmable for up to 10 channels It features Cobra s Express Tuning System that replaces the multi but ton keypad with a three button up down fast design that simplifies d e o tions The uncluttered control area contains a large rotary volume pow er control and nine decade LCD dis play of tuned frequencies and operat ing Status Features of the new scanner in clude one touch memory program ming automatic scanning and manu al tuning channel lockout automat ic squelch telescopic antenna and small 74 inch square footprint The scanner provides coverage in three NS we XS Ta At tuning and programming opera frequency bands Band 1 29 to 29 7 MHz 10 meter Amateur 29 7 to 50 MHz vhf low and 50 to 54 MHz 6 me ter Amateur Band 2 136 to 144 MHz military land mobile 144to 148 MHz 2 meter Amateur 162 4 to 162 55 MHz weather and 148 to 174 MHz high and Band 3 400 to 406 MHz weather 406 to 420 Federal Government 420 to 450 70 cm Ama teur 450 to 470 uhf and 470 to 512 MHz uhf T A companion hand held scanner the Model SR 11 also features the Express Tuning System 10 channel memory and same frequency cover age as the desktop unit It uses four AA alkaline or rechar
16. with M 2 CMA2 B YD 2 FT 2 and IN 2 To attach units such as in to a number you type the number and press the key under IN 2 Like many Hewlett Packard cal culators the HP 48SX is program mable To enter programs into the HP 48SX you begin by pressing the orange arrow and program symbol keys The program symbol key looks like this gt gt To facilitate en tering commands such as iF and WHILE you car bring up a program ming menu bar by pressing the Prg key This lets you enter a command by pressing a single menu key To store a program you place it on the stack with the Enter key and then name it by pressing the single quote C key typing the program name and pressing the Sto key To run a program you type in the name of the HP Kit Turns Dedicated Hardware into PC Software 2 PC using the Kermit protocol The interface kit gives the advantages of using a large monitor and standard QWERTY keyboard for programming the HP 48SX While linked to a PC the HP 48SX can share the computer s printer to generate high quality print outs and use the computer s disk drive to store data and programs Operating the HP 48SX from a PC is like adding software to the computer Unlike traditional software however the HP 48SX can be disconnected from the computer and used alone Say You Saw It In Modern Electronics May 1990 MODERN ELECTRONICS 71 qu e See ee et ee eS EE EES Ee Se
17. 1 999 volts 2 000 3 999 volts and 4 000 15 000 volts respectively Safeware the microcomputer insurance specialists announced a new repair insurance policy for computers Called Safeware Fix It the policy insures against breakdowns as well as external losses and theft The company offers a 20 bonus coverage for licensed registered software Geller Software Labs Montclair NJ has the first spell checking software aimed at database and spreadsheet users and programmers It s said to work with languages such as C Pascal BASIC and others 8 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics Bll NEW PRODUCTS I For more information on products described please circle the appropri ate number on the Free Information Card bound into this issue or write to the manufacturer Soldering Station The Model SA 570 soldering station from OK Industries has an operating range of 600 to 800 F This pro vides high power for multiple appli cations including soldering circuit boards with exceptional thermal de mands A 70 watt heating element with precise temperature control is SA 571 572 claimed to provide excellent stability and repeatability and quick recovery on massive connections In addition the directly grounded tip meets MIL STD 2000 resistance and voltage re quirements This ergonomically designed sol dering station has a low profile small footprint housing that requires min
18. HP 48SX called a scientific expandable calculator has advanced features that let you enter equations just as you would see them in a text book or journal It also allows you to manage unit conversions such as changing feet to meters These ad vanced features complement a long list of others which are packaged in a unit that includes 256K ROM 32K RAM an 8 line by 22 character su per twisted liquid crystal display m Analysis ethod of Wavetor Fourier M Continued on page 70 Say You Saw It In Modern Electronics May 1990 MODERN ELECTRONICS 23 Project An MC68701 Microcomputer Chip Programmer A computer controlled device for programming the MC68701 to customize it for your application NEN By Brian B Beard n the past April issue we fami liarized you with the features and functions of the 68701 sin gle chip microcomputer IC in enough detail for you to utilize it in your own projects This month our discussion focuses on a programmer that per mits you to program the on chip ROM built into the 68701 Programming single chip micro computers can present major prob lems because the unusual pinouts used make them incompatible with stan dard EPROM programmers Low cost programmers often require the additional steps of first program ming a 27XX series EPROM first This EPROM is then used to transfer on board data to the single chip mi crocomputer chip The two step pro cess can be annoyi
19. LC7 40 WATT BURNING CUTTING LASER 20 00 RUB4 HI POWER PULSED DRILLING LASER 20 00 v e BTC5 1 MILLION VOLT TESLA COIL 20 00 v MCPI HI VELOCITY COIL GUN 15 00 a LLS1 LASER LIGHT SHOW 3 METHODS 20 00 EH1 ELECTRONIC HYPNOTISM TECHNIQUES 8 00 lt p v EML1 LOWER POWERED COIL GUN LAUNCHER 8 00 TE JACOB LADDER 3 MODELS ED 10 00 D5 IN THE DARK a 10 1 7 al LEVI LEVITATION DEVICE 10 00 COHIC SECTIONS FMVIK 3 MILE FM VOICE TRANSMITTER 34 50 PFS1K HAND CONTROLLED PLASMA FIRE SABER 49 50 NIG7K HI FLUX NEGATIVE ION GENERATOR 34 50 PGSK PLASMA LIGHTNING GLOBE 49 50 LHC2K VISIBLE SIMULATED 3 COLOR LASER 44 50 HOMING TRACKING BEEPER TRANSMITTER 44 50 LGU6K 2 5 MW HAND HELD VISIBLE LASER GUN 249 50 BTC3K 250 000 VOLT TABLE TOP TESLA COIL 249 50 10G2K 10N RAY GUN project energy without wires 129 95 TKE1K TELEKNETIC ENHANCER ELECTRIC MAN 79 50 VWPM7K 3 MILE AUTO TELEPHONE TRANSMITTER 49 50 ASSISTANCE KITS PROGRAM AVAILABLE e z x ASSEMBLED IN OUR LABS LISTIO INFINITY XMTR Listen in via phone lines 199 50 IPG70 INVIS PAIN FIELD BLAST WAVE GEN 74 50 ITM10 100 000 VOLT INTIMIDATOR UP TO 20 99 50 TAT3O AUTO TELEPHONE RECORDING DEVICE 24 50 PSP40 PHASOR SONIC BLAST WAVE PISTOL 89 50 DNE10 ALL NEW 26 VIVIO COLORED NEON
20. Pa Fig 2 Schematic diagram of the Processor and Memory sections 26 MODERN ELECTRONICS May 1990 Orme per fairly often Therefore since most hobbyists and experimenters will al ready have on hand a suitable regu lated 5 volt dc bench supply this can be used when needed If you do not already have such a supply or wish to make the project self contained you can build any of a number of such supplies from the projects pre sented in Modern Electronics and other periodicals and books Youcan even use a plug in wall type 5 volt supply that is capable of delivering 500 milliamperes or more of current Construction AS you can see from the fairly large number of schematic diagrams pre sented here the Programmer is a fairly complex piece of hardware The large number of interconnec tions makes point to point wiring a task that should be performed only if you are an experienced project build er who is comfortable with the Wire Wrap technique Otherwise it is strongly recommended that you pur chase a ready to wire printed circuit board from the source given in the Note at the end of the Parts List If you are an experienced project builder and have confidence in your abilities to successfully wire together such a complex circuit you can do so using perforated board that has holes on 0 1 inch centers and suitable Wire Wrap hardware But work very care fully and strike off each conductor run as you make it Wh
21. STICK 74 50 LGU20 5 TO 1IMW VIS RED HeNe LASER GUN 199 50 8LS10 100 000 WATT BLASTER DEFENSE WAND 89 50 ASSEMBLED EASY DRDERING PROCEDURE TOLL FREE 1 800 221 1705 or 24 HRS ON 1 603 673 4730 or FAX IT TO 1 603 672 5406 VISA MC CHECK MO IN US FUNDS INCLUDE 10 SHIPPING ORDERS 100 00 amp UP ONLY ADD 10 00 CATALOG 1 00 OR FREE WITH ORDER INFORMATION UNLIMITED UE TERDLSNUSUIEL ISSN AMHERST NH 030371 CIRCLE NO 121 ON FREE INFORMATION CARD LEARN VCR CLEANING MAINTENANCE REPAIR EARN UP TO 1000 A WEEK WORKING PART TIME FROM YOUR OWN HOME Secrets Revealed NO Special cols or Equipment Bo AS P9 v THE MONEY MAKING OPPORTUNITY OF THE 1990 S IF you are able to work with common small hand tools and are familiar with basic electronics i e able to use voltmeter understand DC electronics IF you possess average mechanical ability and have a VCR on which to practice and learn then we Can teach YOU VCR maintenance and repair FACT up to 90 of ALL VCR malfunctions are due to simple MECHANICAL or ELECTRO MECHANICAL breakdowns FACT over 77 million VCRs in use today nationwide Average VCR needs service or repalr every 12 to 18 months Viejos 400 PAGE TRAINING MANUAL over 500 photos and illustrations and AWARD WINNING VIDEO TRAINING TAPE reveals the SECRETS of VCR mainte nance and repair real world information that is NOT available elsewhere Also includes
22. STOCK Street Address City State Zip Stocking all types of converters Panasonic Jerrold Tocom Pioneer Scientific Atlanta Zenith Oak Hamlin Eagle and others Call or write for FREE CATALOG Mon Fri 10 to 6 Eastern Time VIDEO LINK PRINT EACH WORD SEPARATELY Note that P O Box numbers and telephone numbers must be counted as two words each Circle additional words you wish boldfaced at 20 more each initial boldface word is free Minimum charge is for 15 words Free Boidface 2 3 4 Enterprises Inc 520 Glenbrook Rd Suite 202 EE 7 Stamford CT 06906 5 6 j 8 Orders 800 622 9022 Catalog amp Info 203 975 7543 80 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics CABLE EQUIPMENT CABLE TV SECRETS the outlaw publica tion the cable companies tried to ban HBO Movie Channel Showtime Descramblers Converters etc Suppliers list included 8 95 Cable Facts Box 711 ME Pataskala Ohio 43062 CABLE TOCOM VIP TEST CHIP For Models 5503 VIP and 507 Unlike any other turn on this one works Easily installs in just seconds 50 00 each No Calif sales Call 213 867 0081 JERROLD SB 3 substitute Unmodified units in 5 lots only 25 00 each Modified units 35 00 ea in 5 lots No Calif sales Call 213 867 0081 GLOBAL CABLE NETWORK CABLE TV converter and descrambler bar gain headquarters Tocom Scientific Atlanta Zenith Hamlin Pioneer Jerrold 400 DRX JDI
23. Some commands can be issued from the keyboard too as Cirl key sequences MathCAD Features The most striking feature of Math CAD is its ability to display an equa tion on the screen that essentially looks like an equation you would see in a textbook or professional jour nal Whereas most spreadsheets or programming languages use an aster isk for multiplication a slash for division and a caret for ex ponentiation MathCAD uses tradi tional mathematics symbols Addi tionally MathCAD has symbols for integrals derivatives sums prod ucts square roots subscripts abso lute value Greek letters and others One symbol MathCAD uses is not a common math symbol MathCAD distinguishes between an equals sign which is the signal to calculate a result and a definition sign which tells the program the value of a variable The definition sign is en tered by pressing a colon but it is displayed on the screen as a colon plus an equals sign If you want to en ter an equation such as d v t rather than v t 50 you normally use the definition sign Thus if you look closely at a MathCAD screen such as the one shown in Fig 1 defi nition signs predominate You can specify a range of values for a variable by entering an expres sion such as t 1 100 an increment can also be entered The program will calculate a set of answers and May 1990 MODERN ELECTRONICS 17 present them
24. The voltage divider made up of R3 and R4 ensures that the inverting input at pin 6 of C2A is held just above 0 volt When the pulsating dc input at pin 5 returns almost to 0 volt at the end of each half cycle both in puts of JC2A become equal At this point the internal transistor in the output stage of this comparator switches into conduction and dis charges C3 with the resulting wave form shown in Fig 3 C The straight vertical portions of the waveform shown in Fig 3 C are the result of the output transistor in side C2A switching on and discharg ing C3 The curved portions have the almost ideal waveshape cited above to allow the lamp in the projector to begin lighting without wasting the low end of main FADER control R75 and to speed toward full brightness at the high end of the control while be ing linear in the middle of the con trol s range Potentiometer controls R 4 and RIS make up a pair of voltage divid ers Adjusting R 4 assures that at one end of this main FADER control RI5 thelampinthe projector is fully off Hence the inputs going to pins 2 and 3 of C2B are respectively a set potential that can be varied from about 2 volts to 0 volt by R75 and a sawtooth voltage of the same ampli tude With R75 set at mid position the superimposed inputs are as shown in Fig 4 When the voltage set by R75 rises to an amplitude that is just slightly greater than that of the sawtooth am plitude the
25. after selecting Op tions and Input Or you can couch your text within quotes but the quotes remain with the text To access math symbols such as pi theta and others you enter alt letter combinations Derive s Features Derive is a crackerjack with symbolic math The program makes it very easy to simplify factor and expand expressions and to solve equations for one variable in terms of another The program also excels at plotting Derive makes it a simple matter to plot two and three dimensional Say You Saw It In Modern Electronics graphs and to plot more than one graph on an x y two dimensional axis There are also features that let you maneuver the plot after it is con structed such as azoom feature One thing you can t do is print plots di rectly from the program Derive can do arithmetic algebra and calculus and it can work with vectors and matrices To facilitate this the program includes over 100 built in functions that cover areas such as exponentials logarithms trigonometry complex numbers probability and statistics and others If you need a function that the pro gram doesn t address it s easy enough to define it by selecting De clare from the main menu If you re interested in using units of measurement or physical con stants in your equations some are available in separate files supplied with the program To use them you merge the files into the current alge bra window If th
26. all the info you ll need regarding the BUSINESS SIDE of running a successful service Opera tion FREE INFORMATION CALL TOLL FREE 1 800 537 0589 Or write to Viejo Publications 3540 Wilshire BL STE 310 Los Angeles CA 90010 Dept ME 76 CIRCLE NO 157 ON FREE INFORMATION CARD PR tma A T Q5 ot eye MEL e DPA LERRA 7 4 uut rn M x x otx SCATTER TRUTH Fig 4 The HP 48SX has eight plot types contains an equation library of more than 300 science and engineering equations a constants library a fi nance library a periodic table la beled diagrams a multiple equation solver and even a game The way to access the features of the card is by pressing orange arrow and Library Comments amp Conclusions Anyone trying to decide between the HP 48SX and mathematical software that runs on a PC has a few things to consider First of all any scientific calculator has the twin advantages of portability and a dedicated user in terface designed specifically for en gineering problem solving This par ticular calculator has another advan tage it can link to a desktop PC see the sidebar for more information about this feature And not only is the HP 48SX a very powerful scienti fic calculator it also advances the state of the art with features like the equation writer and units manage ment However it is often difficult to implement these and other features without spending considerable t
27. all your laboratory equipment is included in your tuition cost There is no extra charge it s yours to use while you study at home and on the job after you complete your course Earn Your Degree To Become A Professional in Electronics Every CIE course you take eams you credit towards the completion of your Associate in Applied Science Degree so you Can work towards your degree in stages And CIE is the only school that awards you for fast study which can save you thousands of dollars in obtaining the same electronics education found in four year Bachelor s Degree programs Write for Jetails today Send For Your Catalog Today M P a a anars AMO 170 Apt Q eck box for G I Bill bulletin on educational benefits Veteran O Active Duty Mail This Coupon Today AF GAIN Auc CLLZUT RECO CEP lario ECT Ooi LL il CTRA NAA SPCH MHz kHz SEL OMM SQUELCH ide Band Receivers N AN m SQOUELCMN I 3 ee a o H B wu 7 2 M oT DIRECT KEY ENTRY SUSY TUNE 1 F1 3 SCAN E E NM t 6 BEL EH M NM LJ 9 ch E E E o ce ENT E M E MEMORY CH Tee o i LJ RENE Ll NE LLL fd has broken the barriers with it s new line of widebanc receivers built to go the distance Introducing the IC R1 handheld receiver the IC R72 HF rece ver and the IC R100 multi purpose receiver The smallest wi
28. are using pc construction This being the case refer to the wiring guide shown in Fig 10 If you go the Say You Saw It In Modern Electronics HvZWH MOOHS 3A3HIX3 IDNINHVM 5 120 VAC IN RECEIVER GAIN ADJ Fig 10 Wiring guide for receiver pc board point to point wiring route use Fig 10 as a rough guide to component placement Use the same assembly procedure to wire the receiver board as detailed last month for the transmitter board That is start by installing and solder ing intc place the sockets for DIP IC2 Do not plug the IC into the sock et until after you have conducted a voltage check and are certain that the board has been properly wired Proceed with installation of the re sistors capacitors and diodes Make sure the electrolytic capacitors and diodes are properly oriented before soldering their leads into place Next install the transistors and then GAIN ADJUST trimmer R in their respec tive locations Again make sure that the transistors are properly based be fore soldering their leads into place Now install power transformer 77 and coupling transformer 72 in their respective locations Make absolute ly certain that you do not transpose the primary and secondary leads of Say You Saw It In Modern Electronics T and that the notch on the case of T2is oriented along the heavy straight line in the case outline for this com ponent in Fig 10 before soldering any leads or pins int
29. at V in oper ation When the ievel of the liquid rises sufficiently to short out the elec a E E B Fig 6 Examplesof A touch plate sensor triggering of a 555 and B liquid level alarm version of the same principle 54 MODERN ELECTRONICS May 1990 trodes however the voltage on pin 2 V1 drops to a very low level forc ing the 555 to trigger Output Circuits As stated above the output at pin 3 of the 555 can serve as either a cur rent source or a current sink depend ing on how you wire the circuit The output can be made TTL compatible by making V 5 volts dc It can also be made CMOS compatible by matching the 555 power supply po tentials to the levels used in the parti cular CMOS circuit Figure 7 shows how light emitting diodes can used as the load for the 555 Although LEDs are used here almost any load that draws less than 200 milliamperes could be used in stead The usefulness of the 555 is demonstrated by these circuits There aretimes when you might want a LED indication when the output of the 555 is low other times when it is high The 555 can accommodate either need without requiring an interven ing open collector inverter stage In Fig 7 A the LED wired be tween pin 3 and ground requires the 555 to act as a current source When the output is low there is no poten tial across the LED no current flows and the LED is off When the Say You Sa
30. bo ey Micromint s 80C52 BASIC processor chip with on board BASIC language interpreter in ROM offers tremendous flexibility and a wide variety of features eration of all timing required to program EPROMs and EEPROMs The 80C52 BASIC s full language resources allow software development directly on the target hardware The 80C52 BASIC is guaranteed to perform without error at clock speeds from dcto 12 MHz over the full industrial temperature range If power consump tion is critical the 80C52 BASIC offers two reduced power modes that slash power consumption while retaining all RAM register and flag status informa tion The microcontroller s features make it a good choice for intelligent pow er sensitive and temperature sensitive applications The 80C52 BASIC is avail able at 14 50 each in quantities of 100 A Family of Bidirectional FIFOs nte grated Device Technology 3236 Scott Blvd P O Box 58015 Santa Clara CA 95052 has announced a family of bidi rectional FIFOs that are optimized for use in microprocessor communications The family includes four members that are bus matching eight bit peripherals to any size microprocessor Two addi tional members of the family can be used to match 16 bit microprocessors to other 16 bit systems The bus matching biFIFOs with an x18 width on one side and an x9 on the other act as funnels interfacing 16 bit systems with eight bit systems These bi FIFO
31. categories In addition to these you can build compound units such as kilograms per second kg s or add your own units Among its other features the HP 48SX has a built in clock and there fore you can set alarms and do date and time arithmetic a wealth of trig onometric hyperbolic exponential logarithmic and statistical functions and the ability to work with complex numbers vectors arrays and even binary numbers The huge manual that comes with the calculator does a respectable job in terms of style and presentation but is lacking in one important area It fails to give you an overview of the more than 2 100 functions that the calculator can perform For exam ple it would be nice to have a sheet that shows the complete menu struc ture It would also be nice to have a list of all the hidden operations in one place operations such as lower case letters With enough effort the man ual will teach you how to use the cal culator but it doesn t do much to streamline the learning process The serial port on the back panel is used to connect to an IBM PC or Ap ple Macintosh A special cable is needed for this since the port has only four pins The infrared LEDs on the back panel are used to transmit or re ceive information from another HP 48SX or to send information to an in frared printer One of the optional accessories for the HP 48SX is an HP Solve Equa tion Library Application card This card which is
32. check all soldering If you missed any connections solder them now If any connection appears grainy Or otherwise suspicious re flow the solder on it Also clear away any solder bridges especially between the closely spaced pads for the U2 socket and 72 with desolder ing braid or a vacuum type desolder ing tool Do not proceed until you Say You Saw It In Modern Electronics have rectified the problem When you are satisfied that the cir cuit board assembly has been prop erly wired unplug it from the ac line Allow the charges to bleed off the electrolytic capacitors in the power supply Then install U2 in its socket Make sure the IC is properly oriented and that no pins overhang the socket or fold under between IC and socket Operational Checkout Place the transmitter and receiver modules back to back all LEDs on both boards facing away from each other on an insulated surface and plug both units into ac outlets Using a VCR TV or other IR remote con trol transmitter to activate the trans mitter should cause the receiver board to respond This activity will be eviden by the visible LED on that module flashing when any transmit ter key is held down Now place the Extended Play trans mitter and receiver units so that they are face to face all LEDs on both units facing each other This should cause the system to self oscillate from IR feedback You may have to start the ball rolling with a little stim ulus f
33. circuits in which digital pulses or noise spikes appear The spikes can get inside the 555 via its OUTPUT pin where it forces the internal digital chip circui try to reset The diodes shown pro vide some crude isolation for the out put of the 555 If you have ever experienced seem ingly unstable operation from a 555 timer an unusual occurrence with this well behaved chip first deter mine whether the problem is external pulses coupled through pin 3 If so the Fig 10 circuit may well solve the problem In summing up remember that the low cost 555 provides a variety of functions at very low cost for it and any additional components needed to configure a circuit around it In this article we have examined a small number of different ways to interface the ubiquitous 555 timer to the exter nal world at both input and output ends Now it is up to you to broaden your use base of this extremely versa tile chip through further study and experimentation You will be glad you did ME ace UN EID E co Get yours first show it off i You know you will buy one sooner or later why not get yourself up to speed now and have some fun to boot You ll get it all big interactive graphics optional RS 232 serial interface to your PC or MAC infrared to printer or to another 48SX symbclic integrals derivatives and algebra statistics matrices automatic management of units of measurement more than 2 100 funct
34. from an external signal source or through other means Figure 4 A is the schematic dia gram of the circuit for a simple push button switch trigger circuit Pull up resistor R2 is connected between pin 2 and V If normally open push buttor switch S is open the TRIG GER input is held at a potential very close to V But when 57 is closed pin 2 is brought to ground potential Because pin 2 is now at a potential that is less than V 3 the 555 MMV triggers This circuit can be used for contact debouncing in digi tal circuits A circuit for inverting the trigger pulse applied to the 555 is shown in Fig 4 B Here acommon npn bipo lar transistor such as the 2N2222 is used in the common emitter mode to invert the pulse Again a pull up re sistor is used to keep pin 2 at V when the transistor is turned off However when the positive polarity trigger pulse is received at the base of Ol the transistor saturates which S1 N O Switch Fig 4 Examples of A simple push button switch triggering for the 555 timer and B transistor inverter that permits positive going pulses to trig ger the 555 forces the collector and pin 2 of the 555 to near ground potential Shown in Fig 5 are two ac coupled versions of the trigger circuit In both Circuits a pull up resistor keeps pin 2 normally at V But when a pulse is applied to the input end of C3 a dif ferentiated version of the pulse is created at the TRI
35. great reasons to think about QUALITY Only the best performing products make It into our catalog VALUE We offer some of the most competltive prices in the industry SELECTION Choose from over 15 000 in stock items in 30 major categories CONVENIENCE Our TOLL FREE phone lines and liberal terms make doing business with MCM a genuine pleasure SERVICE We could fill a book with examples of our exceptional service But instead send for your FREE Catalog today and let us earn your business CIRCLE NO 164 ON FREE INFORMATION CARD For a FREE ONE YEAR SUBSCRIPTION to the MCM Electronics Catalog Call TOLL FREE 1 800 543 4330 SOURCE NO ME 53 May 1990 MODERN ELECTRONICS 7 BI MODERN ELECTRONICS NEWS lli APPRECIATION DAYS Everyone knows that there s a Mother s Day Secretary s Day and so on But many people aren t so aware of special days that celebrate workers in the electronics industry For example Electronics Technicians are honored each year with a National Electronics Technicians Day in recognition of high performance standards maintained by these professionals It s also a day March 6 to commend the International Society of Certified Electronics Technicians ISCET which this year marks its 20th anniversary of certifying the professional capability of ETs There were 27 578 certified techs at the end of 1989 For info on the certification program call 817 921 9101
36. iK 99 M B 000 X060 HC 18 1 BO 5 63 200 P6307 81 P6206 62 P4154 2200 0 1 09 P4125 560 IK 99 6 3 3 300 P6308 95 P6207 Pa ted 3300 50 109 P4126 680 IK Sa 6 3 4 700 P6309 113 P6208 Paie 3700 50 20 P4127 820 1K 25 6 3 6 80 P6310 14 P6209 1 2 PA15 BOO 1 P4128 The Ox Key volume deicount and service charges ate simple to apply Most tems sold by Digi Key Mey be comoned lor 4 volume drcount Items that are not diacountable are dantdsed by the sufis HANDLING CHARGES NO fofowing the part number After writing your order 1 h ge We pay ali s pprog and surance to addresses i Hawan Canada and Mei WHEN ORDEA aa aY PHONE CALL 1800 304 4539 IAK cail 218 681 6674 BY MAIL SEND YOUR ORDER TO DIGI MEY P O Box 677 Thiet River Falls MM SEDO 00 Less 15 D DIGEMEV GUARANTEE Any pare oF pr al all of the descountatie items and apply the apo sprata recount To tha subtotal acd the Gacountabie items Then add the ser we US 4 Canaia and Mes when chech 2 mosey ori ac competes order Deg Key only stops t eithon the nen eH Almha 9 0 00 624 98 Add 3 00 NET X end Up Mo Charge 00 99 Less 10 Less 20 Less 25 nu T PRICES SUBJECT TO CHANGE WITMOUT NOTICE CIRCLE 8 ON FREE INFORMATION CARD eS a a a es F SHORTWAVE ham scanner radio books Catalog 1 Tiare Publications P O Box m 493ME Lake Geneva WI 53147 MORSE Code No Problem You can in crease your speed no matter
37. is the speed at which it operates espe cially if yoa do not have a math co processor installed in your computer and the way it forces you to cursor around the screen to place equations text graphs and figures in a docu ment This program sorely needs a mouse for navigation Other prob lems with MathCAD are its inability to perform symbolic math and its lack of a true programming language At a price of almost 500 Math CAD is for engineers or educators with high powered PCs who not only need a program to solve problems but also need one that can generate high quality technical documents Derive v 1 60 Getting an A in symbolic math It s hardly a surprise when a comput er program spits out the answer to a math problem such as 2 in a frac tion of a second It isa surprise how ever when a program can perform a relatively simple mathematical exer cise such as finding the factors of x 2x 1 In the first case the solu tion depends on number crunching something computers do exceedingly well In the second case the solution depends on something else and only a program that performs symbolic math can give you the answer Derive from Soft Warehouse 3615 Harding Ave Suite 505 Honolulu HI 96816 808 734 5801 is a program that can do symbolic math just as its prede cessor MuMath did and can crunch numbers too Derive is for the IBM PC and compatible computers re quires 512K RAM and hasasuggest ed
38. is not auto matic in its operation it does give you more interactive flexibility than is possible in Printer mode For ex ample in Modem mode if you pro grammed the 68701 and you cannot remember what program it contains the Programmer lets you determine what the contents are With the Pro grammer you can upload an object file and verify it against the pro grammed data in the EPROM to see if both contain the same data In Modem mode the program will not automatically terminate if a step fails Therefore you can upload and verify again and again until you lo cate the correct file MC Say You Saw It In Modern Electronics Free Product Use the roduct Information free info card How do I get more data Readers can obtain free information on products advertised as well as for some editorially mentioned products Simply circle the appropriate number printed below an advertisement onto the ME Free Information Service card bound into this issue After filling in your name and address just mail the postpaid card Your request will be for warded directly to the advertiser with a mailing label prepared by our reader service department Amazing New Sonic SUPER EAR MICROPHONE Lets You HEAR A WHISPER up fo 100 feet away Just Aim WARNING BEWARE OF CHEAP IMITATIONS Don t be fooied by hearing devices that ook like ordinary radio units Sonic Super Ear is
39. of infrared emitting prod ucts Indi cates presence of infrared in normal light Slim design easily reaches IR emitters on crowded VCH circuit boards This low cost and easy to use instrument will soon become standard equipment for all techni cians in the consumer electronics repair industry CALL TOLL FREE 1 800 338 0531 340 E First St Dayton Ohio 45402 Phone 513 222 0173 FAX 513 222 4644 CIRCLE NO 163 ON FREE INFORMATION CARD Qi MODERN ELECTRONICS THE MAGAZINE FOR ELECTRONICS amp COMPUTER ENTHUSIASTS MAY 1990 CENTRONICS PARALLEL I 4 MODERNELECTRONICS May 1990 16 24 36 44 52 58 64 67 e O 00 82 VOLUME 7 NUMBER 5 FEATURES Special Focus on Math Solving Products MathCAD v2 5 Derive v1 60 amp CMPCALC4 Math PC Software Hewlett Packard s New HP 48SX Scientific Calculator By Joseph Desposito An MC68701 Microcomputer Chip Programmer Computer controlled device programs the MC68701 to customize it for your applications By Brian B Beard Electronic Controller for Slide Projectors Controls on off of projector only when slide is needed and provides fade in fade out for smoother presentations By David Pointing Extended Play Remote Control System Conclusion Operating and construction details for receiver module system checkout and installation and use By Crady VonPawlak Interfacing 555 Timers Hands on look
40. partial fractions is K k H z tk gt i g A k k The beginning of the infinite impulse response h is given by m 0 80 m 1 h M h K a 0 m e k k k Ctr1 PgDn Plot of impulse response 18 MODERN ELECTRONICS May 1990 r exp j 8 d The coefficients K are K k 0 516 0 0915 0 692 1 3014 4 03 4 2 559 6 164 8 384j 12 936 10 819 14 593 15 474 14 593 15 474 12 936 10 8193 6 164 8 384 3 2 Sui Say You Saw It In Modern Electronics SURFACE PLOT 2 2 f x y sinix y 28 i 8 N 4 Surf acm Format i gta Tilt Hidden Lines n Uertical Scale 28 Global Defeult Revert Done Fig 2 A surface plot created with MathCAD also define your own units by using the definition sign MathCAD has 67 built in math functions including Bessel func tions fast Fourier transforms vec tors and matrices Any calculation you can perform in MathCAD on single values you can also perform with vectors or matrices of values Since you can insert figures on the MathCAD scratchpad you might think that the program has built in drawing functions This is not the case If you want to use a figure in a MathCAD document you must cre ate it in a drawing or CAD program that can create HPGL Hewlett Packard Graphics Language files You can then translate the file into MathCAD sketch format and import it into a do
41. per satished but keep the FREE safety decal above cluded with each order Send 8 75 plus 2 75 P amp H to Biophysica inc 902 M West 36th St Baltimore MD 21211 CIRCLE NO 168 ON FREE INFORMATION CARD i Also capacitors transtormers and parts for tube type equipment Send 2 00 for 26 page catalog 688 M W FIRST ST TEMPE AZ 85281 PHONE 602 894 9503 F AX 602 894 0124 m ANTIQUE ELECTRONIC SUPPLY Double your income Computer maintenance service a 10 billion industry IF you are presently servicing office machines or any other electronic equipment computer repair can double your income National research results indicate that computer technicians bill out at double the hourly rate of office machine technicians Tech Serv can put you into computer repair quickly economically and efficiently and with a complete support program including a proven marketing plan We provide I RECOGNITION Nationally recognized trademarks and logos give you immediate recognition as TRAINING Hands on training IBM Compaq Apple and compatibles at 3 separate levels a professional computer repair specialist level 1 8086 8088 Based Machines by being a Tech Serv Authorized Computer a Lem nd u nopi onien in pour mame ata Level 2 80286 80386 Machines Letter DOCUMENTATION Quality and Laser Printers We provide manuals schematics documen Level 3 System Networks Configuration
42. personal computer have at their disposal a variety of ways to tackle mathematical equations One way and probably the most popular is with a high level programming lan guage such as BASIC Pascal or FORTRAN Another is with a spreadsheet program such as Lotus 1 2 3 A third way is with mathemati cal software which is the method we are concerned with in this article Mathematical software has certain advantages over other computerized methods of solving electronic design equations For starters this type of software eliminates the need for pro gramming Another advantage is that the formulas for problem solv ing methods such as matrix algebra are built in Also some of these pro grams are capable of doing calculus which is beyond the scope of pro grams like 1 2 3 Finally mathemati GT Ap ICE EC GT 03r D TER TWEEDREGG Ls ege C CNPERUREUANCOTUEDZMMCIDIOIT GaU KG NR RC CORN AT TX cal software often can display formu las the way you are used to seeing them in textbooks and journals This makes it possible to present design equations to others in a way that is easily understood The programs we review in the fol lowing pages are MathCAD v2 5 from MathSoft Derive v1 60 and a brand new program called CMP CALC4 from UDH Enterprises There are many others of course but these are representative ones After we review the math soft ware we ll take a look at a new prod uct from Hewlett Packard the HP 48SX scientifi
43. retail price of 200 Derive s Operation Derive which comes ona single 5 25 inch 360K floppy is a menu driven system When you start the program the opening screen is divided intotwo areas by a horizontal bar The bot tom portion last four lines of the May 1990 MODERN ELECTRONICS 19 SIN 3 x 1 5 SIN CR nM 3 5 nter option zer SIN 5 x Author Build Calculus Declare Expand Factor Help Jump soLve Manage Options Plot Quit Remove Simplify Transfer moUe Window SIN x Free 66 Derive Algebra Fig 3 Derive lets you mix algebra and plot windows screen contains the menu a prompt line and a status line The first menu you encounter contains 19 choices in two horizontal rows You make a se lection by typing a single letter usu ally but not always the initial one of the command or by moving the highlight with the space bar or tab key not the cursor keys and pressing the Enter key The first choice on the menu Au thor lets you enter mathematical ex pressions or equations into Derive When you choose Author the menu disappears and a prompt appears You can enter an expression such as 53 120r2x 3 oran equation such asy mx b A nice feature of the program is that it understands impli cit multiplication In other words if you type two consecutive letters the program assumes you want them multiplied together After you type an expression
44. standoffs and two sets of dudes hardware beige wall plate and vertical mounting slots for front and rear knob UL and CSA listed CAT TMC 6 sub panel PC boards All enclosures are 5 75 each 10 for 50 00 6 wide X 6 1 4 deep Avaitable In black ivory blue and beige Specity color THUMBWHEEL RMTSH FRONT amp REAR PANEL HEIGHT 1pole 10 position R p n 2 1 4 CAT MB A 7 50 each 10 tor 65 00 decimal encoded K 25 8 CAT MB B 7 75 each 10 br 67 50 ff switches which 3 CAT4 MB C 500each 10 tor 70 00 interlock to make up desired number of digits Terminates 10 AMP SOLID 4 B to 11 pc pins 1 common and 10 poles r Each section is 31 wide X 1 20 high X STATE RELAYS 78 d CAT SWTH 9 1 25 each i5 fer Poo End plates can be added CONTROL Rated 5 5 to 10 Vac operates to form a 94 high bezel END PLATES on 332 Vdc LOAD 10 amp 240 Vac CAT SW 9EC 1 00 per set 2 1 4 X 1 3 4 X 7 8 CAT SSRLY 10B 9 50 each QUANTITY DISCOUNT for 85 00 25 for 175 00 R i cem i 0 for 200 00 100 for 500 00 0 79 dia X 1 1 high New J OPTO SENSOR Q prepped with 1 4 black and red U shaped package with wire leads soldered to the terminais mounting ears 1 8 opening q CATs PPC 210 2 50 each 3 4 mounting ears CAT OSU 6 10 for 22 50 100 for 200 00 50 each 10 for 4 50 100 for 40 00 ORDER TOLL FREE 1 800 826 5432 FAX 818 781 2653 Terms Phone orders must be charged to Vis
45. the lamp and transformer winding would provide a pre bias to warm the lamp filament to around half its TRANSISTOR RADIO OR AMPLIFIER ik B 2 NO 243 or NO 222 TL AUDIO OUTPUT TRANS FORMER Fig 5 An ultra simple incandescent lamp audio transmitter circuit Say You Saw It In Modern Electronics Put Professional Knowledge and a COLLEGE DEGREE in your Technical Career through Add prestige and earning power to your technical career by earning your Associate or Bachelor degree through directed home study Grantham College of Engineering awards accredited degrees in electronics and computers An important part of being pre pared to move up 1s holding the right college degree and the abso lutely necessary part is knowing your fiela Grantham can help you both ways to learn more and to earn your degree in the process Grantham offers two degree pro grams one with major emphasis in electronics the other with major emphasis in computers Associate and bachelor degrees are awarded in each program and both pro grams are available completely by correspondence No commuting to class Study at your own pace while continuing on your present job Learn from easy to understand lessons with help from your Grantham instruc tors when you need it Write for our free catalog see address below or phone us at toll free 1 800 955 2527 for catalog requests only and ask for our degree
46. the menu bar by pressing one of the six keys placed just below the display If you are familiar with RPN cal culators you ll have no trouble per forming operations on numbers The sequence of keystrokes for most op erations is press a number press En ter press another number and then press the operation Sometimes you can press an operation right after pressing the first number such as with the square root key If the above sounds easy it is But be forewarned the HP 48SX has morethan 2 100 functions some hid den in the deep recesses of the menu Fig 2 The HP 48S X includes commands for drawing diagrams 70 MODERN ELECTRONICS May 1990 bar With all of these functions learn ing to do even basic things like enter ing a formula plotting a graph and doingsymbolic math takes a commit ment one that includes reading a manual of over 800 pages And it is unlikely that you can get by without the manual for the HP 48SX learn ing curve is a steep one and perform ing advanced functions is not an in tuitive process The difficulty in learning the HP 48SX stems from its inability to per form functions while in the equation mode To enter the equation mode you press the unit s orange arrow key and Equation key This blanks the display Then you press the alpha key twice to lock it and enter an equa tion such y x which displays just as it would in a textbook Once you ve done this you are staring at a
47. the printer but has also been rede signed to be easier to use and matches that on the IIP Even though the paper cartridge has been refined and smoothed along with the case you can still use any Series II paper cassettes you might have The cassettes look sleeker but are me chanically identical to the older ones Inside the new case are several en hancements that will redefine what H P compatibility means in the beginning of the 90s These include a new internal font technology an upgrade to H P s PCL language PCL 5 and improved output though a technology called Re solution Enhancement The LaserJet III contains the same bit mapped Courier fonts as its predecessor In addition though are two new type faces CG Times a Times Roman face and Univers a sans serif face These two new faces are scalable from 1 point to 999 75 points over 13 inches high in 0 25 point increments They are avail able in medium bold and italic weights One major difference from the old font technology used on the Series II is that the new built in fonts are scalable on the fly As with PostScript fonts you don t have to have a specific type size before you can use it Both the internal scalable fonts the internal bit mapped Courier fonts and any downloaded softfonts can also be rotated Unlike the Series II you no longer need portrait and landscape fonts the portrait fonts can be rotated when producing documents in landscape mode
48. to C4 switches on and drives external triac Q2 into con duction The result is that 117 volt ac line power is applied to the projector through ac receptacle SO Of course at this stage you do not want the timer to time out and switch off the projector until the projection lamp has been faded up the first slide has been viewed the lamp has fully faded down and the change mechanism has advanced to the next slide Early timing out is prevented by D6 The first pulse comes in trig gers the onset of the output pulse and C6 starts to charge through trimmer potentiometer R 6 However each succeeding incoming pulse short cir cuits C6 via D6 and so discharges the capacitor When the lamp is fully on pin 1 of IC2B is low Hence C6 will not charge at all This capacitor will be permitted to charge fully only when R15 has been returned to its fully faded out position and all incoming pulses have ceased Only then can the timed output pulse really begin Pro vided this pulse is long enough in dur ation to permit a third part of the cir cuit to change the slide this time in terval can be adjusted by setting R16 the desired purpose is achieved The remainder of the circuit built around the second multivibrator stage inside the CD4538 and shown as C3B in Fig 1 is used to change the slide before the projector finally switches off Initially with the pro jector off the output at pin6of C3B is low while the input at D7 is
49. 00 28 10 P6347 P6239 28 22 P6348 P6240 25 330 P6349 P6241 25 4 O 2 wie ms 6s ree Pan Can Voh Prien 4 War Resistor Assortments 5 2 20 P6352 P6244 No uaF 1 RS125 3 1 3 9 90 3 300 P6353 7 P6245 P201 3 8 700 P6354 5 46 ta P2012 6 3 4 BOO P6355 P2013 t06 42 000 P63 a 6 r 35 4 7 P6357 P6241 14 g 2015 2f 690 x P6358 26 P6248 72 35 22 P6359 29 P6249 85 33 P6360 y P6250 18 4 P6361 i P6251 82 35 100 P6362 a P6252 60 1 2 Wau Resmior Aasorimente 35 220 P6363 a P6253 e 57330 P6364 6 P6254 95 dard 5 15 P6365 72 P6255 78 35 1 000 P6355 03 P6256 31 35 2 200 P63 P6257 A 35 3 300 P368 24 P6258 32 35 4 700 P6369 47 50 3S 6 8 P63 4 B8 60 Qm e t s o a Va DOS CD 5 WIREWOUND REC RESISTORS Avsisbie in amp 10 We How To Order f Pricing 1 10 100 1 000 100 BO 18 00 5 Watt Metal Resistor Assortments RS105 amp BBETESHNREEXS EK RS205 RS305 4 RS40 4 M K 31 30 7 Pan Cap Vol Price P4535 483 No uF l VAC 10 10 Watt Resisior Assortments 45 23 6 62 R110 8 P4514 012 50 1 26 P4515 0015 50 128 m0 P4516 0 018 132 5 METAL OXIDE FILM RESISTORS Pat 0022 50 135 P4518 027 50 1 38 LBD Avaliabie in 18 2 Wan P451 033 50 t 41 8 0 027 B3 How To Order Take P4520 0039 50 144 P4719 x30 13933 1 5KI and add a t P4521 0 047 50 47 P4720 O M OD P4522
50. 0056 50 i P4721 OC t00 at KW K ttl thes is the E P4973 0068 50 163 4722 0 096 100 P4521 0 082 50 1 73 P4723 O68 100 P4525 0 1 50 69 P4724 0 082 Pa526 Q 12 50 ag P4725 01 10 P4527 Q 15 50 35 V 45 50 D P47 i t Watt Metal Rasisto ssor menis 4 PAIR RS101 5 56 26 95 160 4 P6419 6C P6178 26 166 2 P6179 65 76 95 noai 160 33 P6180 Part Cap Volt Price P4556 0077 50 05 amp P6181 No atl VAC 10 PASS 0033 50 05 RS301 M 76 95 160 10 P6187 P4551 5 amp P4558 0039 50 tan 220 Pe P4552 p P4559 0047 50 2 Watt Hasistor Assortments P6184 iC P4553 7 x P4560 0066 50 2 PETES P4554 0 d X P4561 0068 50 3 P6186 P4555 0022 50 os P4562 082 50 4 7 P618 2501 P6188 250 22 P6189 250 33 P6190 Pals z T L y 3 p z o 2 LZ METAL OXIDE FILM RESISTORS P6193 1 000 X045 08 84 Available in 1 4 Watt 0 2 2 194 1 0000 X066 amp 79 D y3 gt 1 8432 O86 HC 39 96 33 How To Order 8432 x06 HC 1B 42 28 DEBSEESBEREC 59K X GIK X 2 000 x001 HC 33 78 31 Key 2 0000 X068 HC 1i 4 27 amp t 2 4576 X047 HC 33 7a 31 Pricing i 246 XXD NETA me Na 2 9000 1 4 Watt Metal Film Resistor Assortments Part Cap Vott Price p4isn 10000 50 12
51. 00K pot 9620 Capacitor Biox 47pt to 10MFD AM FM TRANSISTOR RADIO KIT with TRAINING COURSE Provides sing tri squ wave trom img to IMH AM or FM capadihty xP 580 59 95 2 20V at 2A 12V al 1A SV at 3A SV at 5A Makes a great school project Model AM FM 108 14 Transistors e 5 Diodes 26 95 Circuits are taid out in systematic order on an over with Freq Counter sized PC board tor easy understanding of the flow 249 Sine Square Triangle Pulse Ramp 2 to 2MHz Freq Counter 1 104MHz of radio signals from antenna to speaker Complete course lociudes all parts PC board and traning manual When completed you mil be proud to dis play your masterpiece 7 Transistor AM RADIO KIT 16 95 15 Day Money Back Guarantee 2 Year Warranty WRITE FOR FREE CATALOG CIRCLE NO 165 ON FREE INFORMATION CARD May 1990 MODERN ELECTRONICS 15 Technology Enhance Your Math Prowess With Software amp Hardware Computer software and hand held calculators ease the burden of complex calculations in different ways Here are in depth examinations of such products that reveal their strengths and weaknesses By Joseph Desposito NES OPCS Mathematical Software For PCs nyone who designs elec tronic circuits invariably finds himself dealing with mathematical equations Usually these are solved with pen and pencil scientific calculator or computer or some combination of each Those who use a
52. 48 9889 is published monthly by CQ Communications Inc Subscription prices payable in US Dollars only Domestic one year 17 97 two years 33 00 three years 48 00 Canada Mexico one year 20 00 two years 37 00 three ycars 54 00 For eign one year 22 00 two years 41 00 three years 60 00 Foreign Air Mail one year 75 00 two years 147 00 thrce years 219 00 Entire contents copyright 1990 by CQ Communications Inc Modern Electronics or CQ Communications nc as sumes no responsibility for unsolicited manuscripts Al low six wecks for delivery of first issue and for change of address Printed in the United States of America Postmaster Please send change of address notice to Modern Electronics 76 North Broadway Hicksville NY 11801 CQ Communications Inc is publisher of CQ The Radio Amateurs Journal Popular Communications Modern Electronics CQ Radio Amateur Spanish CQ and the CQ Amateur Radio Buyer s Guides Say You Saw It In Modern Electronics 97 12 8 SA MENT DESCRAMBL CALL FOR AVAILABILITY Output Quantity Channel SUBTOTAL Shipping Add 3 00 per unit l amp di Prices subject to change without notice ae a in TOTAL California Penal Code 593 D forbids us from shipping any cable descrambling unit to anyone residing in the state of California PLEASE PRINT Name Address City State Zip Phone Number O Cashier s Check O Money Order COD Acct Exp Date Mast
53. 5 and ground When the output is low the load current is zero However when the output is high the load is con nected to V through small internal resistance R and pin 8 Here the output is a current source e RESET pin 4 when low immedi ately switches the output of the 555 at pin 3 to a low state In normal opera Fig 2 Examples of a 555 used as A an output current sink and B an output current source 52 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics tion it is common practice to con nect pin 4 to V to prevent false re sets from noise impulses CONTROL VOLTAGE pin 5 normally rests at a potential of 2 V 3 due to an internal resistive voltage di vider Applying an external voltage to this pin or connecting a resistor to ground changes the duty cycle of the output signal If not used pin 5 should be decoupled to ground through a 0 01 to 0 1 microfarad capacitor THRESHOLD pin 6 monitors the voltage across the capacitor in the ex ternal RC timing network If pin 6 is at a potential of less than 2 V 3 the output at pin 3 is high Alterna tively when the voltage on pin 6 is less than 2 V 3 the output is low e DISCHARGE pin 7 is connected to the collector of an internal npn tran sistor Theemitter ofthis transistor is connected to the ground pin l1 of the 555 When the 555 times out the transistor turns on and can discharge the external timing cap
54. 54 ON FREE INFORMATION CARD PCBoards Layout Software takes the Hassie out of Creating P C B Artwork e Advanced Features Menu Driven e Auto Router amp Schematic Program Available Requirements IBM PC or compatible 364K RAM DOS 3 0 or later PCBoards 99 00 Demo 10 00 HPO 14th Ave South Birmingham AL 35205 205 923 1127 CABLE T V CONVERTERS Jerrold Oak Scientific Atlantic Zenith amp many others New MTS stereo add on mute amp volume Ideal for 400 amp 450 owners tes 1 800 826 7623 L B amp BINC mam ow 4030 Beau D Rue Drive Eagan MN 55122 C ABLE TV EQUIPMENT JERROLD OAK SCIENTIFIC ATLANTA HAMLIN ZENITH MANY MORE CALL TODAY Y Only quality products sold Y Easy to use VSatisfaction guaranteed Y Knowledgeable sales staff Y Most orders shipped within 24 hours CALL FOR YOUR FREE CATALOG j 1 800 228 7404 MEN MAKE uu CONNECTION ET U 5114 er Wood Dr4307 Dept 298 Austin TX 78759 CIRCLE NO 153 ON FREE INFORMATION CARD VIDEO DESCRAMBLERS Al brands Special Combo Jerrold 400 and SB3 165 Complete cable descrambler kit 39 Complete satellite descrambler kit 45 00 Free catalog MJO INDUSTRY Box 531 Bronx NY 10461 0531 T V NOTCH FILTERS SURVEILLANCE EQUIPMENT BROCHURE 1 00 D K VIDEO BOX 63 6025 MARGATE FL 33063 1 305 752 9202 CABLE TV CONVERTERS DESCRAM BLERS A l major brands Are you tired of or dering cable TV equipment and receiving in feri
55. 58 N Fal iN N 4l JN A 74i Ak 91 741 5AN 95N rai Pi af I 4 6N 4C240N hal 8h 4C244N i 9N 453 JN ETI IN 51 FAC aren ral IN 4 IN 41 154N ral N PAS N46 7 Fai S15 7N 18 4S 152N 54 HiOST51AN 6 PalS163N 65 JALS TGAN 69 Jal S 160N 23 4 517 4N Li 5N 41 190N HLS T9 TNI sat JN P3 S1954N 8 234 221N 411 240N S74 1N 4317 74C00 Part Pree cmos Igi 74800 TTL Pre 46 43 45 48 Pine CORPORA TION INTEGRATED MEUS 74HCOD Parl CMOS IHCL H H Xa 4H HOGG IHEIIN HC 7 3N HC7 3AN ing 75 N SN BEN T 26 4 JN T E IHWC T7258 tHC ISIN IHC 1 38K IHC 122334 inc 14798 SHC ISTH 3H 153N Fan 1548 amp 8C157N b 3RCTGON GIN 1 2h 4 Al 4 IN fay 5N 4 IAN 74i SN a aN 4 gaN 4 E t N 4H72351N 4472 32N 148L243X 4MC 244N 1HC 235N 18C25 108 4HC7 5 3N 18C257N 4 IN 4HL 266AN 4HT 280N 7480 299N JM 354N AKC ISEN 4 N SHE 366N IHE y 4 1 i ak HCS 4HC 454 IN Prue Pree 4000 CMDS Part 1 N N h N N 4 N 4 4 N 4 4 4 4 f a 4 4 cf N 4 Ca 02 LN 402 38CN 4 N 1 N N N N z ar Zzzcrczcar INTEGRATED CIRCUITS IN AN7OM1B tN i NP OM2 INTIM N E Memory J Part Price UM 147R 7 N UU MM5257N 2 M325N v N M23278 43290 A i rj M3 A x
56. 9 Self Check with High Stabilized Crystal Oven Oscillator 8 digit LED disptay WE WILL NOT BE UNDERSOLD UPS Shipping 48 States 5 10 Max IL Res 7 Tax a Color Convergence Generator 10MHz Oscilloscope AUDIO GENERATOR 600 ohm Output impedance High Output Voltage Fully regulated and short circuit protected XP 575 without meters 39 95 GF 8015 without Freq Meter 179 C amp S SALES INC 1245 Rosewood Deerfield IL 60015 800 292 7711 708 541 0710 Digital LCR Meter LC 1801 125 Measures Multimeter with Capaciiance and Transistor Tester 55 CM 1500 Reads Volts Ohms Current Capacitors Transistors and Diodes with case AC Current Meter ST 1010 69 95 1000 Amps Data amp Peak Hold 8 Functions Deluxe Case Digital Capacitancs Meter CM 1550 58 95 9 Ranges tpt 20 000utd 5 basic accy Zero control with case Solderiess Brsadboards M 9 Res 01 20M AC Clamp On rent Adapte ST 265 25 00 9430 1 100 pins 15 94 2 170 pine 25 9436 2 860 pins 35 Ail hove Color coded posta 9436 SHOWN Temperature Probe Autoranging DMM M 110CF M 5000 29 95 d Semiconductor iac de Data hold Henge v basic acc dgnal ovem 3 dgt LCD SG 9200 Functlon Generator Decade Blox 129 Blox Low distortion lt 05 ees 9600 10 1 MHz 28 95 Sine Square Wave o 9610 Resistor Blox 47 ohm to 1M 4 1
57. AMEX DINERS CLUB Card Exp Date ME ca SE And Listen PLEASE NOTE This device is not intended for eavesdropping or re cordings of private conversatons Retail Value THE MOST PORTABLE COMPACT SOUND GATHERING SYSTEM EVER RELEASED FOR fee ge Ultra sensitive 4 Shotgun M An volume controled ampi Special Price Now Only SATISFACTION GUARANTEED A tru mwiti directions amgiification System ip pinpoint round _ _ Signature aopREsS cry May 1990 MODERN ELECTRONICS 35 Project An Electronic Controller For Slide Projectors Controls on and off of a projector only when a slide is needed and provides a fade in fade out feature for smoother presentations By David Ponting he constant whine of the fan motor of a projector can be an irritating distraction to both narrator and audience during a slide presentation The Electronic Controller project described here will alleviate this problem Our Electronic Controller for Slide Projectors is a small device that turns on the projector only when a slide is needed and changes to the next slide before it switches itself off Addi tionally it permits each slide to be faded in and out for a smoother less jarring visual presentation The proj ect actually consists of two basic ele ments a phase controlled dimmer circuit for the fade in fade out func tion and a switch on change sl
58. AND REPAIR Price 32 95 Designed for the average VCR user Learn kow to clean the tape path replace belts plus more A must for home maintenance e INTRODUCTION TO VCR REPAIR Price 59 95 Shows how the VCR processes the luminance chromance and audio signals in playback and record modes Servo systems for controlling the capstan motor and video drum cylinder Many more aspects of VCR repair ucANDO Video Tapes Designed Especially For The Electronic Enthusiast Mail check or money order to or call us at 513 548 6113 P O BOX 386 VISA and MASTERCARD accepted GREENVILLE OHIO 45331 BE A SUCCESS WITH GQCANDO VIDEOS CIRCLE NO 156 ON FREE INFORMATION CARD 69 DER NOW OR Enhance Your Math Prowess from page 23 Fig 1 The Equation Writer mode of the HP 48S X displays a formula the way it would appear in a textbook or Journal LCD two expansion slots an RS 232C port and a two way infrared in terface All of this is contained in a product about one third the size of a standard textbook powered by three AAA cells that will last for about six months with normal use Naturally features like the above do not come cheap At a suggested retail price of 350 the HP 48SX can be considered the Mercedes Benz of scientific calculators And you can even order advanced options for the already well equipped base model The options include a serial interface to con
59. C w remote 134 OAK M3SB 60 Quan tity discounts Order yours today VISA MC COD 800 327 8544 EDUCATION INSTRUCTION COMPLETE Digital Training Course Com prehensive overview of Digital Electronics Super handy desktop reference Hundreds of pages illustrations Free newsletter with or der Send 10 00 to Viejo Publications 3540 Wilshire Blvd 310 Dept DG200 Los An geles CA 90010 or call 1 800 537 0589 EARN YOUR THROUGH HOME STUDY Our New and Highly Effective Advanced Place ment Program for experienced Electronic Tech nicians grants credit for previous Schooling and Professional Experience and can greatly re duce the time required to complete Program and reach graduation No residence schooling re quired for qualified Electronic Technicians Through this Special Program you can pull ail of the loose ends of your electronics background together and earn your B S E E Degree Up grade your status and pay to the Englneering Level Advance Rapidly Many finish in 12 months or less Students and graduates in ali 50 States and throughout the World Established Over 40 Years Write for free Descriptive Lit erature OF ELECTRONICS ENGINEERING G E 4251 CYPRESS DRIVE E JACKSON MISSISSIPPI 39212 COOK S INSTITUTE MISCELLA NEOUS ASIAN LADIES want correspondence for friendship marriage SUNSHINE INTER NATIONAL Dept TW Box 5500 Kailua Kona HI 96745 808 325 7707 ALCOHOL BREATH TESTERS
60. CS 37 gt 5V THICK RED UO D S Dae E os O c 9 SC150M au ar o MOC3041 2a O Q o o c o o an FROM LED 1 THICK BLUE eds m 9 nx c THICK GREEN O i C FORWARD FORWARD 5 a C a M R REKEN Q COMMON y YELLOW COMMON REVERSE WHITE REVERSE gt gt 3 A 2 Thick green x 9r 7g 1 and 4 Remote focusing not used in this project Slide advance 9 X Jg 3 White Slide 3 tray reverse 4 y V 5 Common yellow Connected to Pin 2 to advance slide connect to Pin 3 to reverse slide tray by one Live in p Live out Thick red Thick blue Join together to connect switch lamp on when projector switch is in the fan only position MT18 MT2 B FRONT PIN VIEW SC150M Fig 2 Schematic diagram and wiring instructions for small junction box regulate the pulsating dc from point A and make it independent of any but very large variations in the ac in put to the circuit Shown in Fig 3 A is the wave form that appears at noninverting input pin 5 of C2A This com parator stage has an open collector output which means that until the inputs at pins 5 and 6 are the same the output at pin 7 of C24 is effec tively an open switch Initially C3 is charged through R5 and D5 by the waveform at point D shown in Fig 3 B This is clearly a very nonlinear charging current but it does produce an almost ideal wave form at pin 7 of C24A
61. DDR MAKE PORT 1 LINES ALL INPUT 0015 807 86 ff LDAA S FF the normal print command PRINT 0016 809 97 04 STAA P3DDR MAKE PORT 3 LINES ALL OUTPUT FILENAME S19 0017 f80b 97 05 STAA P4DDR MAKE PORT 4 LINES ALL OUTPUT i 0018 f80d 96 02 LOOP LDAA P1DAT READ THE DATA AT PORT 1 In printer mode the Programmer 0019 f80f 97 06 STAA P3DAT SEND IT OUT ON PORT 3 ical odes tali Be FOR Meer MEE ua E performs all operations automatical 0021 f812 97 07 STAA P4DAT PUT THE COMPLEMENT OUT ON PORT 4 ly The result of each step in the pro 0022 f814 7e f8 od JMP LOOP GO BACK AND DO IT AGAIN indi addu S di ce gramming process is indicated by the 0024 fffO ORG OFFFO appropriate LED on the circuit 0025 fffO fa 00 FDB RESET SERIAL COMM 0026 fff2 f8 00 FDB RESET TIMER OVERFLOW board assembly If any step fails the 0027 fff4 8 00 FDB RESET OUTPUT COMPARE appropriate red LED lights and the 0028 fff6 f8 00 FDB RESET INPUT CAPTURE Wh 0029 fff8 f8 00 FDB RESET EXTERNAL INTERRUPT Process ceases at that point en 0030 fffa f8 00 FDB RESET SOFTWARE INTERRUPT programming is successfully com 0031 fffc 8 00 FDB RESET NONMASKABLE INTERRUPT i 0032 fffe 8 00 FOB RESET RESET pleted all four green LEDs will be lit 0033 When power is first applied to the Programmer all LEDs come on for a second to check their operation The program then checks the on board and Port 4 Data Direction Registers which sets all bits of both ports to out
62. DT72521 and the IDT72511 are 94 93 and 85 43 respec tively in a 68 pin PLCC package sI 66 MODERNELECTRONICS May 1990 Say You Saw It In Modern Electronics Wi PC CAPERS _ By Ted Needleman I have to admit to being a bit ambivalent about Hewlett Packard Its test equip ment 1s first rate as are its calculators On the other hand I ve never been all that impressed by the company s Vectra PC line considering it overpriced and with a keyboard not up to H P s fine Standards as demonstrated on its other equipment And PAM H P s Personal Application Manager gives me hives it s just nowhere near as well done as many other DOS shells including some inexpensive shareware products such as Magee software s Automenu Where H P does shine in the PC world though and shine brightly is in the area of laser printers As detailed in last month s review of the LaserJet IIP Hew lett Packard introduced the world s first affordable desktop laser printer in 1984 and has lead the market ever since When I reviewed the 1 495 IIP last month I wondered at H P s marketing After all the IIP gave you everything ex cept the speed of its Series II and a few things such as rotatable fonts that the more expensive printer doesn t offer It seemed destined to blow away the sales of its mid range laser printer line The questi
63. ED is used alone Power MOSFET Lamp Flasher Figure 3 shows a simple incandescent lamp flasher circuit that uses a solid state switch instead of a relay The two cross coupled gates form a multivibrator that oscillates at a frequency determined by C1 When the value of C is 4 7 microfa rads the circuit oscillates at a rate of about 1 Hz The output of the oscillator goes to the gate of VN67 or similar power MOSFET Ql which is switched off and on by the changing state of the oscilla tor s output The lamp is switched on when Q is conducting Supply voltage for the Fig 3 circuit should not exceed the lamp s rated volt age Power dissipation of the lamp should not exceed Q s power rating In some applications when L switches on sup ply voltage might fall enough to alter the flash rate If this is a problem simply dis connect the lamp from the oscillator s power supply and provide it with a sepa rate supply The source lead of Q should be connected to the ground side of both supplies For more versatility replace the simple two gate oscillator with a 555 or 7555 CMOS 555 oscillator chip Modulating a Filament In the spring of 1966 when was a student at Texas A amp M I was experimenting with a lightwave communication system along adark country road The receiver s detec tor was a solar cell installed inside the re flector of a 6 volt lantern light The re ceiver emitted a buzz when it was pointed at a
64. END IT OUT ON PORT 3 COMPLEMENT IT PUT THE COMPLEMFNT OUT ON PORT 4 GO BACK AND DO IT AGAIN SERIAL COMM TIMER OVERFLOW OUTPUT COMPARE INPUT CAPTURE EXTERNAL INTERRUPT SOFTWARE INTERRUPT NONMASKABLE INTERRUPT Say You Saw It In Modern Electronics Ly a SY EAE PE EY ELI ee ee VORHER ee ee ae Listing 2 Assembler Listing shown the Programmer acts as a printer On the other hand if the jumper 1s present the Programmer operates as a modem In Printer mode the Programmer 0001 EXAMPLE ASSEMBLY LANGUAGE PROGRAM FOR THE 68701 0002 0000 P1DDR EQU 00 PORT 1 DATA DIRECTION REGISTER 0003 0001 P2DDR EQU 01 PORT 2 DATA DIRECTION REGISTER monitors the Parallel and serial 0004 0002 PIDAT EQU 02 PORT 1 DATA REGISTER Ports and accepts data from which 0005 0003 P2DAT ZQU 03 PORT 2 DATA REGISTER 0006 0004 P3DDR EQU 04 PORT 3 DATA DIRECTION REGISTER ever is active The S19 output of an as 0007 0005 P4DDR EQU 05 PORT 4 DATA DIRECTION REGISTER sembler can be sent to the Program 0008 0006 P3DAT EQU 06 PORT 3 DATA REGISTER 2d 0009 0007 P4DAT EQU 07 PORT 4 DATA REGISTER mer just as though it is a printer For 0010 example onan MS DOS system you 0011 f800 ORG F800 START OF INTERNAL EPROM Id simpl he P 0012 f800 Of RESET SEI DISABLE MASKABLE INTERRUPTS would simply connect the Program 0013 801 8e OO ff LDS SOOFF INITIALIZE STACK POINTER mer in place of your printer and type 0014 804 7f 00 00 CLR P1
65. Free details call 1 800 537 800 442 9333 0589 or writeto Viejo Publications 3540 Wil InA Shire Bivd 310 Dept FX300 Los Angeles CA 90010 CABLE TV EQUIPMENT CABLE MATE INC Are You Tired of Paying Outrageous Fees All makes and models of cable equipment shipped within 24 hrs Quantity discounts For free catalog send S A S E to Cable Mate Inc 214 N Main St Algonquin IL 60102 C O D orders accepted CALL FOR PRICES TODAY 800 422 0525 708 658 2121 E No Illinois orders Hours 8 00 am 5 00 pm central time CB TRICKS OF THE TRADE I amp II Tricks and Tricks ll plus a free set of plans for CB Super Modulation Special 40 00 Order each book separately for 19 95 C O D Orders Accepted Medicine Man CB P O Box 37 Dept A Clarksville AR 72830 501 754 2076 COMMUNICA TIONS M E ANTENNA SOFTWARE PROGRAM Cal Z KICKER Throw your super Zenith culates antenna lengths for radios scanners amp away Guarantees non flashing 279 95 CB s Specify Commodore or IBM Send each 229 95 10 or more Jim 1 800 969 5 00 Antenna P O Box 321 Rankin IL 3576 FLPO Inc P O Box 081426 Racine 60960 WI 53402 n n eS CLASSIFIED ADVERTISING ORDER FORM Mail this form with payment to MODERN ELECTRONICS Classified Dept 76 N Broadway CABLE TV Hicksville NY 11801 CONVERTERS Name IN
66. GGER input of the 555 Diode DJ clips the positive going spike to 0 6 or 0 7 volts pass ing only the negative going pulse to the 555 If the negative going spike May 1990 MCDERN ELECTRONICS 53 Fig 5 Examples of A ac coupled triggering of a 555 using pulses and B push button version of the same circuit can counteract the positive bias pro vided by R2 sufficiently to force the voltage lower than V 3 the 555 will trigger A pushbutton switch ver sion of this same circuit is shown in Fig 5 B A touchplate trigger circuit is shown in Fig 6 A Pull up resistor R2 has a very high value 22 meg ohms shown The touchplate con sists of a pair of closely spaced elec trodes As long as there is no exter nal resistance between the two halves of the touchplate the TRIGGER input of the 555 remains at V However when a resistance is connected across Finger gt resistance lt l Touchplate L Tm i am A the touchplate the voltage V 1 drops to a very low value If the average fin ger resistance is about 20 000 ohms the voltage drops to Vi V X 20 x 103 R2 20 x 10 Thus when R2 is 22 megohms the voltage drops to 0 0009 V This is consid erably less than the V 3 trigger ing criterion for the 555 The same concept is used in the li quid level detector circuit shown schematically in Fig 6 B Once again a 22 megohm pull up resistor is used to keep pin 2
67. MOS microcontroller with on board BASIC Based on Intel s popular 8052 the 80C52 BASIC contains a full BASIC interpreter in on chip ROM This implementation of BASIC includes the following features BCD floating point math built in real time clock access to programs in RAM EPROM or EEPROM built in radix conversion from hex to decimal and deci mal to hex ability to handle interrupts in BASIC or assembly language and gen Ve ee a a a a Le eee May 1990 MODERN ELECTRONICS 65 Say You Saw It In Modern Electronics o s D PROCESSOR 3231 j lt 3 T due 2 3 ediki BUFFER PI ucc K U F E 4HCT245 3h aq ace o gee mmaa ADO NPO O MAL t pe G B8I y uf 01 A po di ako eee sim a L P7 i4 B7 li e i BO 7 3 BELL 2p PF p LLL L m LES E a P1 a O al 16 b 4 adh 4 Bar Ld 4 RI OG a4 RS a oF 8 4A a gn I BIi ak E R D A B EN 1 h4P3 1 s TXO 1 C Amd DQ 2 eINT 40463 3 eINT Pa e BWR ae 1 f a FT E S r4 had 2 T DEM pin ASI gt p ij E pim ih q 8631 OR MICROMINT S 8eCc52 B SIC Sil ADO E zl AO AD2 AD3 2 s 4 La ra B la a ONI 4 amp GNO To ld di LL P Aid EM Edo E J Alg ia Ai J fl mod iB Ajs F T Cs GNO r 1 GNO SOs 1s 20 T
68. MPCALC4 don t have a language but let you run commands automatically this gets them a rating of 2 Derive has neither a programming language nor a way to ex ecute commands automatically so it receives a 0 If you re interested in the programming capabilities of the prod uct you could use this information to guide your choice of product If on the other hand you re more interested in a program s ability to do symbolic math Doo RR E ERE eee EE EEE stack or storage area the number appears on the screen just below the cursor prompt When a second number is entered it replaces the first on the top of the stack and the first is moved down one place To perform a mathemati cal operation on the two numbers on the stack you enter the operator at the prompt The answer which ap pears instantly then moves to the top of the stack and the other numbers are erased All numbers on the stack are displayed in scientific notation with 10 decimal places If you want to store a number you enter it and then enter a command such as STO A where A is a label The number appears in a Storage area at the bottom of the screen with the GO Gee mcewemm EH AS EEE SE EN NNNM CON NOE A Guide to Selecting Math Software and Hardware Comparing Product Features Features Calculates range of values Performs symbolic math Factors equations Finds roots of an equation Handles complex numbers Does matrix algebra Does unit conversion
69. N control through its access hole in the rear panel clockwise until the LED just begins to glow very brightly Then back off counterclockwise ro tation until the LED either suddenly goes dark or suddenly glows dimly If the LED glows dimly even when the GAIN control is adjusted fully or nearly counterclockwise excessive noise is present on the ac line You may leave the unit plugged into this outlet or test others in the room for quieter operation Alternatively you can make either or both of the fol lowing modifications In the transmitter module replace C7 with a 0 1 microfarad polyester ACCESS tes for rear A and front B panels of receiver FRONT PANEL TEMPLATE BOTH UNITS enclosure Say You Saw It In Modern Electronics May 1990 MODERN ELECTRONICS 49 or Mylar capacitor This slightly re duces the threshold of the IR circuit but otherwise leaves unaffected the 18 foot plus range of the project In the receiver module place a 1 000 ohm resistor across in parallel with C7 This effectively lowers the Q of the LC tank circuit to reduce noise induced ringing Neither of these modifications will noticeably reduce the performance of the circuits Once you have set the receiver threshold play a prerecorded video cassette through the VCR After pressing PLAY check the remote TV receiver it is assumed that you have run video and audio cables from the VCR to the re
70. N 198 M337K AN A ie Ui a M3 18K aN ai MMSI TAN MJII AN M Kf AN 6 ber M AN M an w340K AN M ANI AID amp D A M n Part Pree M A A e M AN 4 AOCO d LK t A oN MILON TE N MILAN EEL y aN EM LI Ww K N7EM N M3507 N78M0 N MISAN T Li LY iN 20M 1 aA M380N INJAM N M 4 Ny gM B h M381N NUM N M382N NIEM D on M 1 NBM M38 iN IN 730 BICA M v LN DLN M3E7N 1N LON M389N N 1 CN M390 N LCN MIIN N de JAAN M N Y ww f M N amp MISHIN Interface A hs P Part Price M s 3 apay M N deli ME ul N79 MSOC N IN M N N N M N 4 W N M 4 amp 9 IN j gt N Dog Ney Pac N541F V Part No Praa 2854 D N M M N M N N b 4 N MPS555 A N MPSES 14 i 1 N MP k 7h N M ie Mr A Mr M IN v Ni iN MP 1036 N M N 4 i 284 A MPS AG X 7411328 WPS A4 N MPSA N1 i wars sa N MF 4 N i PN 784234 N MF v N PN A N N PN LI N A N TE iN 90 PN NA IN 60 A Na N 60 Ph A Ni 1 PNJ N PNJ 26440 PNI 2N4 1 P N4 PN i 2N Lal N PN364 N5 PRI54 y N P4164 N5 N PH364 N5 N 49645 N5 N PN4121 H N PN417 LI N 4 PN12 t 4 L1 NW A N4243 14 N b N PN425 IN 0 Pa 4 aNd 4 PN42 2N54 1 MPS 998417 74 254 MES PHa N641 M 4 PN 1 800 344 Od AK Puerto Rico 218 681 6674 FAX 218 681 3380 TWX E 9103508982 DIGI KEY CORP SILICON TRANSISTORS PANASONIC SU SERIES DISC CAPACITORS 9 12001 225
71. T ZY vo 7 A9 OOO0t ET YSdW 223 v Z2071 t4207 ev NNN a ww lt 4 eo T OTi J c Ss ee v h F R _ _ 4 vT9 ee so m e e a 3 eua AXOdA aio NOBI 0 t O H2 62 HhoZv o T arty Tuo 2 9g EEO VeceeNne E TO 823 vH MRE gan ven 2 9 d NOT Zy M2 M22 go 1Cd 35HH 0WHAHI 6V3HIT NOS TW CQY NIY9S S53299Y va May 1990 MODERN ELECTRONICS 45 Say You Saw It In Modern Electronics tive going transients that may enter through the bandpass filter stages A variable level voltage divider bias is provided for Q by R3 and trimmer potentiometer R This cir cuit provides a simple method of ad justing overall receiver gain sensiti vity for setting optimum perfor mance for a given location within your home Resistor R2 sets the col lector current for transistor Q7 When the received control signal is passed to the base of Q a current flows through the emitter collector junction of Q7 which causes the col lector voltage to appear as a ground low potential to the input of U2 Resistor R2 holds the input to one gate of U2 in a normally high state until a control signal is received CMOS hex Schmitt trigger invert er U2 cleans up the amplified signal that appears at the collector of Q7 It also provides additional drive cur rent to accommodate both the LED visual indicator and the IR driver fi nal output sta
72. YOUR ON E S Ea E al S URC B E MAY 1990 2 50 CANACA 3 50 Special Focus On Math Solving Products MathCAD v2 5 Derive v1 60 amp CPMCALC4 Math PC Software Hewlett Packard s New HP 48SX Scientific Calculator Also Featured E A Programmer for the 68701 Microcomputer Chip Electronic Control for Slide Projectors Interfacing 555 Timers To the Real World Plus Hands On Look at the New Loaded Hewlett Packard LaserJet Ill Laser Printer Experimenting With Ircandesc2nt Lamps e Latest New Esc ane Computer Products more a KENWOOD pacesetter in Amateur Radio CLOCK OFF CLOCK 2 ret 4 A RAT S N 1 A D Ld STEP HF VMF N89 FLOCK PII E ae CCT SQL e NOTCH c F PIT 3 3 Ed o AF RF ae Aj WM v di de J AC NB2 NOTCH FAST NB IF SHIFT E I lap E UU ih 5000 um E vr ui ee E gt 50 QQ y li High perfgrmance i rec iyers Scan the entire frequency range from 100 kHz to 905 MHz with Kenwood s R 5000 R 2000 and RZ 1 Listen in on foreign music news and commentary Monitor local police fire and other public aD Safety services as well as the Marine channels and the many other services 50 MHz and above Super easy Other useful features include programmable scanning large built in speaker 110 volt AC or 12 volt DC operation with optional DCK 2 cable VHF
73. a MasterCard or Discover Minimum order 10 00 Add 3 50 per order for shipping handling CA residents add sales tax Quantities limited Mail orders may be paid by check No C O D CALL TOLL FREE FOR A FREE 60 PAGE CATALOG ELECTROLs 2191 T ZOnrAP ERO NZ OGRA PO CIRCLE NO 160 ON FREE INFORMATION CARD gl AMC Sales te 155 ARRL TCI ees 160 All Electronics Antique Electronic Supply B amp B Inc PavrERC RE LAM Biophysica Technologies Inc 77 165 C amp S S3les sees TP Cable Connection eese x Cable Mate Inc Pda RO Cleveland Institute of Elec Cov III Command Productions T a Med 147 Consolidated Electronics 161 Cook s Institute Damark International bint ha 154 Deco Industries TH 8 Digi Key Corp Juj 79 168 EduCALC TUDIN 159 Global Cable Network Hi Grantham ca E E EE EERS 151 Heath Co APEE eee 115 ICOM T Cov I 121 Information Unlimited E GI 41 Kenwood pevucee Cov RI Listen Electronics i i 164 MCM Electronics toby 146 Mouser Electronics ae 10 Medicine Man CB M NRI Schools 2 13 75 153 Nu Tek Electronics vaa T8 PC Boards DE RW t 22 T8 Pacific Cable Co Inc 5 163 Parts Express International ka TEF 167 smith Desig
74. a main program that begins with the label LOOP Initialization begins by disabling all maskable interrupts It then sets the stack pointer to address OOFF which is the top of the RAM internal to the 68701 Next it clears the Port 1 Data Direction Register at address 00 Ac cumulator A is loaded with the value FF Note that this instruction uses im mediate addressing f so the Accumu lator is loaded with the literal value FF not the data stored at address FF Final ly Accumulator A is stored at Port 3 Listing 1 Assembly Language Source Code EXAMPLE ASSEMBLY LANGUAGE PROGRAM FOR THE 68701 PlDDR EQU 00 PORT P2DDR EQU 01 PORT PlDAT EQU 02 PORT P2DAT EQU 03 PORT P3DDR EQU 04 PORT P4DDR EQU 05 PORT P3DAT EQU 06 PORT P4DAT EQU 07 PORT ORG SF800 RESET SEI LDS SOOFF CLR P1DDR LDAA SFF STAA P3DDR STAA P4DDR LOOP LDAA P1DAT STAA P3DAT COMA STAA P4DAT JMP LOOP INTERRUPT VECTORS ORG FFFO FDB RESET FDB RESET FDB RESET FDB RESET FDB RESET FDB RESET FDB RESET FDB RESET RESET 1 2 1 2 3 4 3 4 DATA DATA DATA DATA DATA DATA DATA DATA DIRECTION REGISTER CIRECTION REGISTER REGISTER REGISTER DIRECTION REGISTER DIRECTION REGISTER REGISTER REGISTER START OF INTERNAL EPROM DISABLE MASKABLE INTERRUPTS INITIALIZE STACK POINTER MAKE PORT 1 LINES ALL INPUT MAKE PORT 3 LINES ALL OUTPUT MAKE PORT 4 LINES ALL OUTPUT READ THE DATA AT PORT 1 S
75. a 100 kHz filter im plementation with a total harmonic dis tortion of 0 005 or less Applications for the device include an tialiasing filters smoothing filters and tracking high frequency lowpass filters The LTC1064 3 is a monolithic lowpass Bessel filter that provides a linear phase response over its entire passband An ex ternal TTL or CMOS clock programs the filter s cutoff frequency with clock to cutoff frequency ratios of 75 1 or 150 1 The LTC1064 3 has low wideband noise and low harmonic distortion even for in put voltages as high as 3 V rms The LTC1064 3 is available in a 14 pin DIP and 16 pin surface mounted SOL package Pricing in quantities of 100 and up for the military temperature range is 27 85 and for the commercial tempera ture range is 9 95 CMOS Op Amps Require Only 40 Micro amps National Semiconductor 2900 Semiconductor Dr P O Box 58090 Santa Clara CA 95052 has introduced new quad and dual micropower CMOS 250 200 lt L3 E 150 ac Z gt 100 a a zz if 50 0 2 4 6 8 10 55 25 125 C 12 14 16 EE Va National Semiconductor SUPPLY VOLTAGE V National Semiconductor s new micropower operational amplifiers require a current of only 40 pA per amplifier The curve shows current versus voltage for the LPC662 operational amplifiers that require a sup ply current of only 40 pA per amplifier The devices also feature true
76. a Ham Radio operator and he s having the time of his life talking to new and old friends in this country and around the world You can do it too Join Andy as he communi cates with the world Enjoy the many unique and exclusive amateur bands the millions of fre quencies that Hams are allowed to use Choose the frequency and time of day that are just right to talk to anywhere you wish Only Amateur Ra dio operators get this kind of freedom of choice And if it s friends you re looking to meet and talk and you can too with Amateur Radio is the hobby for you The world is waiting for you If you d like to be part of the fun if you d like to feel the excitement we can help you We ve got all the information you ll need to get your Ham license Let us help you join more than a million other Hams around the world and here at home Who are we We re the American Radio Relay League a non profit representative organ ization of Amateur Radio operators For information on becoming a Ham operator circle number 110 on the reader service card or write to AMERICAN RADIO RELAY LEAGUE Dept CQ 225 Main Street Newington Conn 06111 Tris space donated by this publication in cooperation with the American Radio Relay League HE 1 T B 1 R D Battery operated InfraRed Detector Parts Express introduces the first Battery operated InfraRed Detector pen This compact device will instantly confirm operation
77. about the size of a credit card fits into an expansion slot inside the calculator You can get to this slot by removing a section of the back cover The application card 72 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics Now NRI trains you to be today s expert security electronics technician as you install and troubleshoot state of the art security systems in your own home and auto Violent crime theft fire they re facts of life in the U S today But now there s good news too All across the nation people are fighting back with high tech electronic security systems In fact Americans will spend over 17 billion dollars on security services and equipment by the year 1991 For you this new consumer demand for electronic security systems means even more good news It means a breakthrough opportunity to get in on the ground floor of a booming new industry Now no matter where you live you can start a high paying career even a business of your own in stalling servicing and maintaining residen tial and commercial security systems Best of all NRI s ready now to give you th hands on security electronics training you need to _ get started fast You train witb and keep a closed circuit television camera mount and 9 monitor state of tbe art fire intrusion alarm control panel with digital dialer remote entry keypad passive infrared motion detector smoke detector remot
78. acitor V POWER SUPPLY pin 8 connects to the positive rail of the power sup ply that drivesthe 555 timer chip and usually any other circuitry Good practice dictates that a 0 1 to 1 0 microfarad decoupling capacitor be used between pin 8 and ground Monostable Operation The monostable multivibrator MMV also called a one shot multi vibrator produces a single output pulse of fixed duration when trig gered by an input pulse as illustrated in Fig 3 A The output of the one shot snaps high following the trigger pulse and remains in this condition for a predetermined duration When this time expires the one shot is timed out and so snaps low again The output of the one shot re mains low indefinitely unless an other trigger pulse is applied to it The 555 timer can be operated as a monostable multivibrator with suit able connection of the external cir cuit as in Fig 3 B It is this mono Say You Saw It In Modern Electronics Pin 2 trigger Pin 3 output A Fig 3 Timing diagram A of a one shot multivibrator built around the 555 timer and B details for assembling a 555 a one shot multivibrator stable multivibrator configuration of the 555 that we will use as the basis for our discussions here Input Triggering The 555 MMV circuit triggers by bringing pin 2 froma positive voltage down to a potential of less than V 3 Triggering can be accom plished by applying a pulse
79. adiation This is commonly known as blackbody radiation As the temperature of an ob ject increases the flux of the radiation it emits increases and conversely its wave length decreases Blackbody temperature is specified ac cording to the Kelvin scale in which 0 Kel vin K equals 273 16 degrees Celsius The terin degrees is not supposed to be used with the Kelvin scale but often is Only when the temperature of an ob ject becomes very warm does the radia tion it emits become visible As evidence of this consider that the temperature of an electric heating element that emits a cherry red glow is in excess of around 1 000 K The filament of a white hot tungsten halogen lamp may reach 3 400 K If the filament could be heated to 6 000 K without melting it would emit light as white as that emitted by the sun It s appropriate to ask why the light from an object at 1 200 K appears to bea monochromatic red while that from an object at 6 000 K is white The answer is that blackbody radiation has a very broad spectrum and is not monochro matic Indeed the peak wavelength of a cherry red heating element at 1 200 K is around 2 4 micrometers in the infrared In other words the red glow from the heating element is only a small portion of the radiation it emits Most of the radia tion from the heating element is invisible The peak wavelength of sunlight is around 555 nanometers in the green The fact this happens to match the
80. akes job opportunities available to you through the bimonthly school paper Cos Sumer Electronics kilitary Electronics Personal Training From A Renowned Faculty Unlike the impersonal approach of large class room study CIE offers you one on one instructional help 6 days a week toll free Each CIE lesson is authored by an independent specialis backed by CIE instructors who work directly with you to arswer your questions and provide technical assis tance when you need it Se q Cy Print Name F dress C ty State Zip 4 Z CIE Wo id Headquarters Cleveland Institute of Electronics inc 776 East 17th St Cleveland Ohio 44114 O YES Please send me your independent study catalog For your convenience W CIE will have a representative contact you there is no obligation Area Code Phone No Practical Training At Your Own Pace Through CIE you can train for your new career while you keep your pres ent job Each course allows a gener ous completion time and there are no limitations on how fast you can Study Should you already have some electronics experience CIE offers several courses which start at the intermediate level State 0f The Art Facilities amp Equipment In 1969 CIE pioneered the first elec tronics laboratory course and in 1984 the first Microprocessor Laboratory Today no other home study school can match CIE s state of the art equipment And
81. amp In Your Own Home f you re anxious to get ahead and build a real career you owe it to yourself to find out about the Cleveland Institute of Electronics CIE can help you discover your career potential in the fast growing field of high tech electronics A career that will challenge and excite you every day reward you with a powerful feeling of personal accomplishment and deliver a level of financial security you may have only dreamed of before As the leading school in home study electronics CIE nas helped over 150 000 students in the U S A and over 70 foreign countries get started in this exciting fielc To find out how CIE could be helping you read on then send for a CIE catalog TODAY A Growing Need For Trained Professionals The career opportunities shown here are only a few of the challenging high paying careers yeu could enjoy as an electronics technician You could be the brains behind the scenes of an exciting TV broadcast trouble shoot life saving medical equip ment design exetic new aeronautics systems CIE s job oriented programs offer you the quickest possible path to the career of your dreams And CIE also features military and union re training to build on what you already know Dozens 0f Fascinating Careers To Choose From Even if you aren t sure which career is best for you CIE can get you started with core lessons applicable to aif areas of electronics As you advance CIE m
82. an t tell if Manufacturer Address LaserJet III Hewlett Packard Co 800 752 0900 Price 2 395 1 MB memory board 495 2 MB memory board 990 T3 Complete w mini transmitter and 5 vdc RF receiver Fully assembled including plans to build your own auto alarm Write for more informatlon Quantity discounts available Check Visa or M C 24 95 30 days retund Add 3 shipping VISITECT INC Dept M 415 872 0128 PO BOX 5442 SO SAN FRAN CA 94080 Descramblers Converters Some Of The Best Prices In Town T J SERVICES 313 979 8356 PREPARE FOR THE FUTURE NOW E e ELECTRONICS AND YOU PART 1 DC Price 32 95 Series circuits parallel circuits combination of series parallel circuits OHMS law voltage current and resistance e ELECTRONICS AND YOU PART 2 AC Price 32 95 AC theory coils transformers capacitors filter circuits and how they are used in actual circuits e ELECTRONICS AND YOU PART 3 SEMICONDUCTORS Price 32 95 An introduction into the world of semiconductors Starts with semiconductor theory then proceeds into 15 different semiconductor devices Shows how an integrated circuit is designed and built e ELECTRONICS AND YOU PART 4 POWER SUPPLIES Price 32 95 Starting with the transformer then to various types of rectifier circuits Filter circuits voltage protection Trouble shocting different parts of the power supply e VCR MAINTENANCE
83. and local extremes as shown in Figs 3 A through 3 E as well as find the area under a curve The unit can also display graphs in eight formats function bar charts histograms scatter plots conic section polar parametric and truth plots see Fig 4 In equation writer mode you can enter integral signs derivative signs summation signs sigma greek let ters and superscripts Any division operation is shown as one number over the other About the only thing you can t doisenter subscripts Once you enter an equation you can per form algebraic operations such as collecting like terms or solving for one variable in terms of another and the new equation also can be dis played just as it would be in a text book One algebraic function that you can t perform is finding the fac tors of a polynomial You can how ever solve quadratic equations The HP 48SX can solve calculus problems too It does differentia tion integration and summations and will also do Taylor s polynomial approximations However you may not always get answers in the form that you expect For example taking the derivative of x with respect to x should give you an answer of 2x The calculator gives you an answer that shows the derivative of x with respect to x multiplied by 2x raised to the 2 power a correct answer but not ex actly what most people expect The unit management function of the calculator converts 148 different units in 16
84. and or should any front end component fail and cause the same effect as excessive current drawn by the IR diodes Voltage divider bias of thesignal is provided for Q3 by R5 and R6 The required IR energy is generated by high output IR emitting diodes D and D2 Buffer capacitor C2 main tains the high current levels required for proper operation by D and D2 during reception and re transmission When a positive going signal is present at the base of Q3 a current flows though the emitter collector pn junction of the transistor This for ward biases D and D2 The rate and frequency at which Q3 D and D2 operate exactly matches that of the 46 MODERN ELECTRONICS May 1990 signal originally emitted by the hand held IR remote control transmitter used with the project though it is at a greatly increased energy level A simple regulated dc power sup ply for the receiver circuit is provided by TI BRI Cl C3and UI Construction For the receiver you can use either a printed circuit board or perforated board that has holes on 0 inch cen ters and suitable Wire Wrap or sol dering hardware on which to mount and wire the components If you opt for pc construction and wish to fabri cate your own board use the actual size etching and drilling guide shown in Fig 9 Alternatively you can pur chase a ready to wire board from the source given in the Note at the end of the Parts list From here on we will assume that you
85. annister or tray It would be an easy procedure for you to turn on the projector and then fadeinthe lamp However it is more convenient if starting to move the Se 38 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics fade up is the way to switch on the projector This is accomplished in this Controller by the Fig 1 circuitry made up of C3A Q1 IC4 and Q2 and their associated components One half of a CD4538B dual mon ostable multivibrator shown as C34 is used here as the controlling element of the circuit for switching on the projector Assume that the projector is off and FADER control RI is set so that the lamp would be off if the projector were switched on Under these conditions the output from pin 1 of C2B would be high As soon as the fader starts to move up however a series of initially nar row pulses are initiated the first of which can be used to trigger C3A When this stage is triggered its out put at pin 10 goes high This causes Ql to switch into conduction in turn causing the LED inside optical isola tor C4 to light When this occurs Fig 3 Waveforms that appear at various points in fade in fade out circuitry A pulsating dc with an amplitude of about 8 5 volts at point A B truncated pulsating dc with an amplitude of 6 2 volts at point D and C waveform at pin 7 of IC2 of about 2 volts Say You Saw It In Modern Electronics the triac internal
86. assembly CR1 CR2 CR3 1N4148 switching diode D D2 LD271 1R emitting diode in T13 package D3 Yellow light emitting diode in T1 package Q1 2N2222A general purpose npn silicon transistor Q2 Q3 MPSA 3 Darlington tran sistor U1 7808 8 volt regulator in TO 220 package U2 CD4584BC CMOS Schmitt Trig ger Inverter Capacitors C1 1 000 pF 35 volt electrolytic C2 1 000puF 16 volt electrolytic C3 C4 C5 4A7 F 16 volt electrolytic C6 1 0uF 250 volt metalized polyester C7 0 1uF 50 volt metalized polyester C8 C9 0 0334F 50 volt metalized polyester Resistors 4 watt 5 tolerance R2 10 000 ohms R3 39 000 ohms R4 R7 6200 ohms R5 R6 1 000 ohms R8 150 ohms R9 R 10 47 ohms 4 watt R1 50 000 ohm upright pc mount noninductive trimmer potentiometer Miscellaneous F1 ampere fuse or No 32 solid bare wire see text L1 470 amp H low power inductor with iron or ferrite core and axial leads voltage test U2 should not be in its socket at this time turn the thumb wheel of trimmer potentiometer R7 fully counterclockwise and place the circuit board assembly on an insu lated surface Plug the receiver s line cord into an ac outlet and touch the hot probe of the meter to pin 14 of the U2 sock et The meter should register a read ing of 8 volts If you do not obtain the proper reading touch the hot MASTER PARTS LIST T1 12 6 volt ac 300 mA p
87. at real world use of this ubiqui tous and very versatile IC timer chip By Joseph J Carr COLUMNS Electronics Notebook Experimenting With Incandescent Lamps By Forrest M Mims III Solid State Devices Filters FIFOs and Other Devices By Joseph Desposito PC Capers Laser Wars Hewlett Packard s New LaserJet III Laser Printer By Ted Needleman DEPARTMENTS Editorial By Art Salsberg Letters Modern Electronics News New Products Advertisers Index Say You Saw It In Modern Electronics EDITORIAL STAFF Art Salsberg Editor in Chief Alexander W Burawa Managing Editor Dorothy Kehrwieder Production Manager Elizabeth Ryan Art Director Barbara Terzo Artist Pat Le Blanc Florence V Martin Phototypographers Hal Keith Illustrator Bruce Morgan Photographer Joe Desposito Forrest Mims III Ted Needleman Curt Phillips Contributing Editors BUSINESS STAFF Richard A Ross Publisher Art Salsberg Associate Publisher Dorothy Kehrwieder General Manager Frank V Fuzia Controller Catherine Ross Circulation Director Melissa Kehrwieder Data Processing Kathleen Bell Customer Service SALES OFFICE Modern Electronics 76 North Broadway Hicksville NY 11801 516 681 2922 FAX 516 681 2926 Jonathan Kummer Advertising Manager Emily Kreutz Sales Assistant Offices 76 North Broadway Hicksville NY 11801 Tele phone 516 681 2922 FAX 516 681 2926 Modern Electronics ISSN 07
88. attery is said to provide up to 2 hours operating time This battery can be charged in side or external to the system the lat ter with an included external battery charger Additional batteries are available as options as are an inter nal 2 400 bps modem 1 MB mem ory upgrade and choice of protective carrying cases The computer measures 13 87 x 12 25 x 3 25 inches when closed and weighs less than 12 5 lbs 3 499 CIRCLE NO 123 ON FREE INFORMATION CARD to require or add rear speakers to the viewing area The self contained unit has a built in amplifier two speakers and digital sound processor In use the unit is placed atop or near the TV screen to obtain the surround sound effect It can be connected to any video source that has audio output jacks or to a stereo receiver if the TV receiver is connected to an external hi fi system Internal circuitry sends a variably delayed audio signal throughout the listening environment Effect inten May 1990 MODERN ELECTRONICS 9 Say You Saw It In Modern Electronics n IN ELECTRONIC COMPONENTS Whether you order 1 part or all 22356 ra MOUSER stocks B55000 oud e ale n nA o men t 2 ELECTRONICS Sales amp Stocking Locations Natlonwide CIRCLE NO 146 ON FREE INFORMATION CARD CONSOLIDATED E LE CY RANTES THE ULTIMATE ELECTRONICS CATALOG Order your 260 page catalog and price list with over 14 000 money saving electronic parts a
89. auses the lamp to be modulated by an audio frequency tone p D A 62 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics B SIL Lk INN TRANSISTOR X EL QZ CN EC un IRE DE RR c amp TEXT TRANSFORMER AMPLIFIER Fig 7 A transistorized incandescent lamp voice and tone transmitter Frequency can be changed by altering the values of R1 C1 or both The circuit should be powered by three 1 5 volt cells connected in series Before connecting the cells to the circuit how ever connect the microphone and care fully check all wiring to make sure no er rors have been made When power is ap plied the lamp should glow at around half its normal brilliance If it glows a dim yellow in color increase pre bias cur rent by connecting a second 10 ohm resis tor across R10 When you speak into the microphone the lamp filament should flicker Press ing 7 may cause the lamp s brightness to change but the lamp will not flicker Most dynamic microphones should work well with this circuit but high im pedance types will not work Though I used a TIP3029 for Q4 other npn power transistors should also work Going Further Try placing a magnifying lens between a small incandescent lamp and a white wall As you move the lens back and forth an image of the lamp s filament May 1990 MODERN ELECTRONICS 63 Sav You Saw It I
90. c expandable calcula tor Besides the regular features of a scientific calculator it has graphics features that make it competitive with math software for the PC MathCAD version 2 5 Software for creating formulas that look good calculate too Of the many virtues of MathCAD v2 5 MathSoft 201 Broadway 16 MODERN ELECTRONICS May 1990 Cambridge MA 02139 800 MATH CAD the one that is most enamor ing is its ability to make the display on your computer resemble a page from an electronic design text or journal MathCAD which has a sug gested retail price of 495 can inte grate equations graphs text and fig ures on your computer display and the equations and graphs are live This means you can assign values to the variables of an equation to obtain results graph those results automat ically and then if desired change the variable values to obtain new re sults and a new graph Besides the main program Math Soft also sells applications packs for a variety of disciplines The price of the Electrical Engineering Applica tions Pack see sidebar is 99 MathCAD Operation MathCAD for the IBM PC and com patibles the program is also avail able for the Apple Macintosh comes on two 5 25 inch disks or one 3 5 inch disk both formats are included in the package To install the pro Say You Saw It In Modern Electronics gram you simply copy the files to your hard disk MathCAD s opening sc
91. c mount power transformer T2 100 4H coupling transformer TOKO No 707V X A03YUK Printed circuit board or perforated board with holes on 0 1 inch centers and suitable Wire Wrap or soldering hardware see text socket for U2 polarized ac power cord plastic strain relief optional see text suitable enclosure hookup wire solder etc TRANSMITTER Semiconductors BR1 50 PIV bridge rectifier assembly CR1 1N5819 Schottky diode D1 SFH205 photodiode D2 T1 green light emitting diode Q1 TIP120 power Darlington transis tor TO 220 package Q2 MPSA 13 Darlington transistor U1 78L05 5 volt regulator U2 CD4584BC CMOS hex Schmitt trigger inverter U3 TDA4060 infrared amplifier with agc Capacitors C1 1 000 pF 35 volt electrolytic C2 47 pF 50 volt electrolytic C3 47 F 16 volt electrolytic C4 47 yF 35 volt electrolytic C5 4 7 yF 16 volt electrolytic C6 1 pF 250 volt metalized polyester C7 0 22 nF 16 volt metalized polyester C8 0 33 yF 16 volt dipped tantalum C9 0 1 uF 16 volt metalized polyester C10 0 1 u4F 100 volt metalized polyester probe of the meter to INPUT pin 1 of regulator U1 where you should ob tain a meter reading of approximately 20 volts If you fail to obtain the proper reading at either or both points on the circuit board assembly unplug the receiver module from the ac line and carefully check over all component installations and wiring and soldering Make sur
92. capability 108 174 MHz with the VC 20 option dual 24 hour clocks with timer and even voice frequency readout with the VS 1 option VywIrisij LE PX v xv Pe da R 5000 The R 5000 is a high performance top the line rece er with 100 memory channels and direct keyboard or main 41701 ter Wale mami anc ect iion selection n LI i RZ 1 Wide band scanning receiver a ee oe te oe ea ee e Optional Accessory e PG 2N Extra DC cabi a A R 2000 THU The R 2000 is an all band all mode receiver with 10 memory channels and b many deluxe features such as program mable scanning dual 24 hour clocks with timer all mode squelch and noise Dlankers a large tront mounted speaker 110 volt AC or 12 volt DC operation with the DCK 1 cable kit and 118 174 MHz VHF capability with VC 10 option Optional Accessories R 2000 e VC 10 VHF converter DCK 1 DC cable kit for 12 volt DC use R 5000 e VC 20 VHF converter e VS 1 Voice module e DCK 2 for 12 volt DC operation e YK 88A 1 AM filter e YK 88SN SSB filter e YK 88C CW filter e MB 430 Mounting bracket Other Accessories e SP 430 External speaker e SP 41 Compact mobile speak cere SP 50B Mobile speaker e oe Deluxe head pnon S e HS 6 Li eignt neaapnones e HS 7 Min Phodddhoncs KENWOOD KENWOOD U S A CORPORATION 2201E Dominguez St Long B ach CA 90810 P O Box 22745 Long Beach CA 90801 5745 CIRCLE 41 ON READER SERVICE CARD Andy is
93. catalog Accredited by the Accrediting Commission of the National Home Study Council GRANTHAM College of Engineering 10570 Humbolt Street Los Alamitos CA 90720 May 1990 MODERN ELECTRONICS 61 CL fF C Si PRESS FOR TONE BCE CToP SEE TEXT Fig 6 An incandescent lamp modulator driver circuit Be anFCC LICENSED ELECTRONIC TECHNICIAN Earn up to Aa 30 an hour and more U Learn at home in spare time S No previous experience needed No costly School No commuting to class The Original Home Study course pre pares you for the FCC Commercial Radio telephone License This valuable license is your ticket to thousands of exciting jobs in Communications Radio TV Micro wave Computers Radar Avionics and more You don t need a college degree to qualify but you do need an FCC License No Need to Quit Your Job or Go To School This proven course is easy fast and low cost GUARANTEED PASS You get your FCC License or money refunded Send for FREE facts now MAIL COUPON TODAY L om 9 o po cai e es mcr COMMAND PRODUCTIONS 1 FCC LICENSE TRAINING Dept 220 I PO Box 2824 San Francisco CA 94126 i Piease rush FREE details immediately B NAME I ADDRESS city STATE ZIP operational brilliance This reduced the lamp s rise time and greatly improved its ability to be modulated by audio frequen cies The rheostat permitted the current to t
94. circuit board assembly into its enclosure If you usea plastic box for the enclosure make sure that no en try exit conductors on either side of the board can touch any others Also fit a small heat sink onto the triac on this board Secure the board to the enclosure via the hardware that secures the heat sink into place R15 ON z WIPER IK mmm LED 1 Reverse Lc n7 7 2 AP si E oe f lt q i en gt Forward 1C5 K On Projector Socket TAB rw Ce Blue o5 R i al Thick Red Thick Green Yellow PG Plug White 5V LED1 Slide Forward Common Slide Reverse From Main Board Fig 7 Wiring diagrams for A main and B junction box circuit boards 42 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics If you use a metal enclosure for the junction box assembly make certain that the inside of the box is well insu lated from any part of the circuit board assembly The recommended triac on this board has an isolated metal tab that can be used to secure the circuit board assembly into place Additionally the metal box will pro vide the required heat sinking Checkout amp Use Make sure no DIP IC or optical iso lator is plugged into any socket on ei ther board Clip the common lead of a dc voltmeter or multimeter set to the dc volts function to circuit ground Plug the line cord of the Controller into a
95. convenient ac outlet and touch the hot probe of the meter to pin 8 of the C7 socket and note the reading obtained It should be 5 volts If it is not touch the hot probe to OUT pin 3 of I C and note if the reading is 5 volts If you still do not obtain a reading of 5 volts touch the hot probe to IN pin 1 of Z C Now the reading should be approximately 8 volts Switch your multimeter to the ac volts function Touch the hot probe tc the junction between R2 and D4 The meter should give a reading of approximately 6 volts ac If you fail to obtain the correct reading at any of the points cited unplug the project from the ac outlet and correct the problem Do not pro ceed until you do obtain the correct reading at each point Using the hot probe of the me ter check the voltages at pins 3 and 16 of the C3 socket and pin 1 of the IC4 ICS and C6 sockets In all cases the correct reading is 5 volts Failure to obtain the proper reading at any socket pin requires remedial work to rectify any wiring or compo nent installation error Once you obtain the proper read ings at all points cited unplug the project from the ac line and discon nect the meter from it Carefully plug Say You Saw It In Modern Electronics Small junction box plugs into connector on slide projector via a multiple con ductor cable This box must be located as near as possible to the p
96. cord and sparingly tin with solder Pass this end of the line cord through its rubber grommet lined hole and tie a strain relieving knot in it about 4 inches from the end inside the enclo sure Separate the conductors a dis tance of about 1 inch and slip over each a l inch length of small diame ter heat shrinkable tubing Twist to gether one line cord conductor and one power transformer primary lead and solder the connection Do the same for the other line cord conduc tor and transformer primary lead Then slide the tubing over the con nections to completely insulate them Ke Fader starts to close Projector lamp fully out Inputs into IC2 Pins 2 and 3 Ke Projector lamp starts to tade e Fader fully closed I l l Output IC2 Pin 7 I Output IC3 Pin 10 EES T1 Projector switches oft Le IC3 starts to time out about two seconds Output IC3 Pin 6 i About 2 second while T2 Dunng T2 the slide tray C8 charges about 1 second advances one position i while IC3B A i times out HFe Fader starts to open r Projector lamp fully lit Inputs into IC2 Pins 2 and 3 te Projector lamp starts to fade up J Vv vov J i l Fader fully open dh de ee we i 1 I i t oa Output IC2 Pin 7 Output 1C3 Pin 10 l IC3A triggers but cannot yet start to time out Project
97. ct heat the envelope of a gas filled lamp will become much hotter than that of an evacuated lamp Even better performance can be FLASHING LED Ri 1 5K Fig 2 An improved relay lamp driver Say You Saw It In Modern Electronics achieved by adding to the fill gas a trace of a halogen such as bromine or iodine This sets up a regenerative chemical reac tion that greatly increases the permissible Operating temperature of the filament while simultaneously restoring the tung sten atoms that are boiled away Here s what happens In an ordinary lamp tungsten atoms boiled away from the incandescent fila ment can condense on the comparatively cool inside wall of the glass envelope Ina halogen lamp evaporated tungsten atoms combine with the halogen to form tungsten bromide or tungsten iodide While this gas does move toward the in side walls of the envelope it does not con dense there when the envelope is heated to 200 to 250 degrees C by the filament which may have a temperature of from 2 800 to 3 400 K As the gas circulates back toward the heated filament it disassociates back in to tungsten and halogen vapor when the temperature exceeds 2 500 K This pro cess occurs in close proximity to the fila ment thereby causing tungsten atoms to be deposited onto the filament and its Supporting wires The cycle then repeats as additional tungsten is liberated and combines with halogen vapor The very high filament temp
98. cument To enable you to print out your journal like documents MathCAD supports most popular printers and plotters including postscript print ers And as if this weren t enough MathSoft devotes 18 pages of the Reference manual to describing its printer and plotter drivers sothat you can add your own if necessary At this point you may be wonder ing if MathCAD has any drawbacks other than its sluggish operation on Say You Saw It n Modern Electronics PCs and XTs It does MathCAD cannot do symbolic math Anytime you want MathCAD to solve an equation it attempts to calculate a numerical answer Thus you usually need to provide values for all con stants and all but one of the variables in an equation MathCAD s 262 page user manu alis very nicely done often including one or twc screen shots on a page to explain operation of the program Also included is a Reference manual and a Quick Reference manual What Is missing however is a Quick Start section in the manual Comments amp Conclusions With its beautiful displays as an in ducement MathCAD can easily lure you into giving up your old calcula tor spreadsheet or self written pro grams And for some the switch to MathCAD may prove very satisfy ing MathCAD is a full featured and powerful program that especially ex cels in its ability to display equations in mathematical notation and solve and graph those equations What you may find distracting though
99. cy is deter mined by a control voltage making the device ideal for real time analog filtering 270K CONTROL SUMMER TL082 Fig 1 Precision Monolithics SSM 2044 voltage controlled filter oscillator is shown here connected as a four pole low pass electronic music filter 64 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics under microprocessor control A unique feature of the SSM 2044 is its on chip resonance control which can produce a low distortion sine wave for use in voltage controlled oscillator vco applications With a dynamic range of 90 dBand 1 MHz bandwidth the SSM 2044 is a low noise alternative to switched ca pacitor filters ina wide variety of applica tions including antialiasing and recon struction filtering The SSM 2044 can operate with supply voltages ranging from 5 V to 18 V and therefore offers better pc board lay out flexibility than some CMOS devices The SSM 2044 s performance and characteristics are guaranteed over the 0 C to 70 C temperature range The pro duct is priced at 2 60 each in quantities of 100 and is available in 16 pin epoxy DIP packages Eighth Order 100 KHz Low Noise Fil ter Linear Technology 1630 McCarthy Blvd Milpitas CA 95035 has announced the LTC1064 3 an eighth order filter with a maximum corner frequency of 100 kHz and only 80 V rms total wideband noise The new device requires no exter nal components for
100. d here Just use the features in the Table along with others that may interest you as a product selection checklist performs complex exponential loga rithmic trigonometric hyperbolic and square root operations The pro gram also has a few functions that it can perform such as DUP dupli cate SWAP and Swi Switch Automated procedures can use any command that can be entered at the prompt plus a few others which amounts to about 12 commands in all There is also a way to call one file from another and to designate a file as asubroutine Although the author states that CMPCALC4 has a pro gramming language there are no conditional testing or looping com mands available Included on the CMPCALC4 disk are three other useful programs EDCALC4 QUINT and POLSL V Say You Saw It In Modern Electronics EDCALC4 is a text editor for the procedures you create with CMP CALC4 QUINT is a program that solves up to fifth degree polynomials with real coefficients POLSLV is a program that solves up to 20th de gree polynomials with real coeffi cients The difference between QUINT and POLSLV is the ap proach used to solve the polynomials Although the user guide isn t pro fessionally printed and contains some punctuation errors it does a good job of explaining the program and gives some valuable examples from the author s engineering experi ence In one example he explains how the program can help you plot amp
101. deband handheld available today the IC R1 continuously covers YOOkHz 1300MHz with AM FM and Wide FM modes This tiry receiver measures just 1 9 W x 4 0 H x 14D Easy operation is a sna ap with the IC RI s Dual Frequency Selection direct keyboard and rotary tuning 00 memories and a 24 hour clock completes the world s smalles full featured handheld receiver Install the IC R100 at home or in your car Listening pleasure is guaranteed T That Go The with continuous coverage from 100kHz 1856MHz in AM FM and wide FM modes Monitor VHF air and marine bands emergency services government as well as amateur stations 121 fully programmable memory channels multiple scanning system an automatic noise limiter built in preamplifier and attenuator clock with timer and built in backup lithium battery make the IC R100 the perfect package for mobiling or base operation The IC R72 continuously receives 100kHz 30MHz in SSB AM and CW modes with very high sensitivity An optional UIS rovides FM reception Additional features include Noise bianker five scanning systems AC DC operation internal backup batter built in clock and ICOM s DOS System The IC R72 boasts a 100 dB wide dynamic range while Distance an easy to access keyboard provides convenient rogramming versatility The easy to operate 172 is superb for short wave listeners EM IC R1 IC R72 and IC R100 join ICOM s current line of professional quality Se
102. distant neon sign More surprising were the ringing sounds caused by the headlights of some passing cars Later tried pointing a flashlight at t 60 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics the receiver which produced nothing but changes in noise level Tapping the flash light with a pencil caused the receiver to emit the same ringing sound produced by the car headlights The ringing is caused when the filament vibrates in and out of the reflector s focal point You can make a lightwave receiver to observe this phenomenon by connecting a silicon solar cell to the input of a bat tery powered amplifier Alternatively you can assemble the basic lightwave re ceiver circuit shown in Fig 4 In this cir cuit Q is any npn phototransistor Do not place your ears close to the speaker since it is capable of emitting very loud sound levels Therisetime of miniature low voltage lamps may range from 10 to 200 millisec onds This means a small lamp can be modulated at audio frequencies Indeed during World War ll some amateur ra dio operators experimented with optical communicators based on voice modulat ed incandescent lamps G Wataghin and R Deaglio of Tori no Italy first published a brief note on this method in a 1933 issue of the Pro ceedings of the Institute of Radio Engi neers Vol 21 No 10 pp 1495 6 Hol li
103. ds the new data byte from Ullin Fig 3 C After processing the new data byte U8 strobes ACK acknowledge at P16 low The rising edge of ACK clears the UJ2C UI12D flip flop which clears the BUSY line to allow the host computer to send the next data byte The only power required by the Programmer is 5 volts dc at 500 milli amperes The 21 volts V needed to program the EPROM is supplied by the Dc to Dc Converter circuit shown schematically in Fig 4 A Trimmer potentiometer R70 permits May 1990 MODERN ELECTRONICS 25 E adjustment of V to the required 12 volt level needed for pro gramming This 21 volts is applied to RESET pin 6 of U8 only when the internal EPROM is being pro grammed Power is distributed to the various ICs that make up the pro grammer as specified in the Table that accompanies Fig 4 A Switch ing of V is accomplished with the cir cuit shown schematically in Fig 4 B The Programmer does not feature its own ac operated 5 volt dc power supply While it isa valuable tool the Programmer is not the type of proj ect that you will use every day or even Qum NOR 00000000 2223 Boy ace Te jl QU E m E E m EI OHANMTROR OANMENOR PPMMMMMM vvvxveveee aaaaaaaa 204000000 5 fa a ta 4 ajajaja bel ak il E e a wn QaNneu et Qannag w gE et ed ed d o4 NON Fara amp Ere RAR ARRAN acaed im N i Die b Ri AAA a fs
104. e This impedance can vary from 3 to 14 ohms To accommodate these variations the receiver circuit has been optimized for a 3 ohm worst case operation As the incoming signal is passed to the secondary of 72 pins 3 and 4 it is stepped up by a turns ratio of ap proximately 10 1 Capacitor C7 across this winding forms a high Q LC resonant tank circuit that is de signed for optimum operation in the frequency range of 30 kHz to 60 kHz which is the anticipated frequency range of the received signal 44 MODERN ELECTRONICS May 1990 This signal is then passed to the se ries parallel bandpass filter made up of C8 C9 and L The circuits thus far described extract and passively amplify only those signals impressed onto the ac power lines by the Ex tended Play carrier current transmit ter while rejecting the majority of transients noise and signals pro duced by non related carrier cur rent devices After filtering and amplification the received signal is passed to cur rent limiting resistor R4 and clipping diodes CR and CR2 Thetwo diodes limit signal amplitude to a normal ized level of approximately 1 4 volts as seen by transistor Q7 Reverse biased switching diode CR3 across CR and CR2 clamps against nega Fig 8 Complete schematic diagram of receiver module circuitry Say You Saw It In Modern Electronics WtHLN3N THOS OvAOZ2Y 3NT1 LOH J3HIM 5MY Z ts V amp dW 26 9
105. e control auto alarm witb motion detector ignition disable relay and siren NRI Discovery Lab for circuit demonstrations and band beld multimeter with 3 2 digit readout Make good money in ay challenging career as a M security electronics technician even start a profitable new business of your own complete electronic alarm systems in your own home and auto testing and trouble shooting working alarm circuits You actually safeguard your own property while gaining Right away you get the skills you need to install and service all security systems NRI s at home Security Electronics training gives you solid electronics know how plus a complete working knowledge of popular security devices in use today Yeu learn how to install and service magnetic contacts and pressure mats microwave ultra sonic and passive in frared detectors personal identifica tion systems and electronic listening devices even cen tral station alarm systems and today s most sophisticated fire warning equip ment But that s not all Your hands on training includes state of the expertise you need to move fast into an the art CCTV equipment plus home and exciting career even a business of your auto electronic alarm systems you keep own as today s expert security electronics NRI gives you hands on experience with to technician day s newest most popular security systems Send for your FREE catalog today as
106. e each com ponent is in its appropriate location and those that require polarizing and 48 MODERN ELECTRONICS May 1990 C11 0 01 4F 100 volt metalized polyester C12 C13 220 pF 16 volt monolithic ceramic Resistors 4 watt 5 tolerance R1 100 000 ohms R2 39 000 ohms R3 6 200 ohms R4 R5 1 000 ohms R6 330 ohms R7 47 ohms watt R8 R9 4 7 ohms watt Miscellaneous F1 ampere fuse see text T1 12 6 volt ac 300 mA pc mount power transformer T2 Coupling transformer TOKO No 707V X A043YUK Printed circuit board suitable enclo sure see text ac line cord with plug sockets for U2 and U3 fine copper mesh for Faraday shield see text hookup wire solder etc Note The following items are available from Scientific Engines P O Box 2295 Ever ett WA 98203 Complete Extended Play transmitter and receiver kit includes pc boards enclosures all electronic compo nents copper screen and self adhering front panel overlays 119 95 plus 3 50 P amp H additional receiver and transmitter kits 62 95 each plus 2 50 P amp H ready to wire transmitter and receiver pc boards 32 50 per set of two plus 2 50 P amp H Mail orders make payment via certified check or postal money order Visa MasterCard orders call 206 348 7754 Washington residents please add state sales tax to all orders I special basing are properly installed Turn over the circuit board assem bly and
107. e not scary commodity like products Moreover some U S compa nies are even slinking back to producing DRAMs or leasing equipment for startup companies to do the same But money is still tight industry leaders aren t much interested in cooperating with others the government is still hesitating about pro viding any industry assistance in what ever form Viewing the recent U S Memories de bacle it ll likely be a long time before a similar venture is attempted So I d guess that the DRAM market will remain a for eign country commodity in the same way that oil is And we ll just have to suffer the availability and price levels as eco nomic times dictate lt Atte Say You Saw It In Modern Electronics Reader Project Updates enjoy the construction projects pre sented in Modern Electronics and some times see ways to improve on a published project A case in point is the Two Line Telephone Answering Machine Inter face that appeared in the February 1990 issue In thearticle the author noted that polarity of the phone lines is critical submit here a modification that creates a bridge circuit for seizing the line that is GREEN Bl LETTERS Jill not in use The original circuit equivalent is shown in Fig 1 By adding three diodes per phone line as shown in Fig 2 the full wave bridge circuit created makes polarity a non issue If the top line in Fig 2 is positive as re quired in the or
108. e temperature tends to sta bilize after about 4 minutes If the projector is used intermittently for short periods it never gets hot enough to reach even this stabilized temperature Provided the time period is ade quate between the end of T and the end of T in Fig 5 A this can be ad justed with R76 consecutive slides can be shown without the projector turning off between each slide If the projector is still running when the slide type FADER control is opened again it will continue running with out a break and maintain the correct sequence of events Although the Electronic Control ler described here was designed spe cifically to work with Kodak Ekta graphic slide projectors almost any other projector can be controlled by it Even a projector that uses a low voltage lamp powered by an internal transformer can be faded in and out with no change in component values in the circuitry With a low voltage high wattage lamp the triac specified for Q5 must be bolted to a sizable heat sink per haps the metal body of the projector itself However provided a break in the supply to the lamp can be found the circuit will yield good control of the brightness of the lamp and all other slide functions Photos by Teresa Hernandez Say You Saw It In Modern Electronics Discover Your Career Potential In The Fast Growing Field Of High Tech Electronics CIE Gives You The Training You Need to Succeed At Your Own Pace
109. e the same 812 H x 5 2 W x 57s D enclosure dimensions Both are fully water resistant as a result of their structural foam baffles and en closure The terminal connections provide waterproof electrical con nections and permit single handed cable insertion In addition to the key slot on the backs of the enclosures for direct wall hanging via a nail or screw the speakers come with a pivot type C bracket that mounts via a ball joint bracket The latter arrangement al lows the user to position the speaker for best sound in a given area The Model SB30 is an enclosed two way system that contains a 4 polypropylene woofer and 1 soft dome tweeter Crossover is at 3 5 kHz Frequency response is rated at 75 Hzto20kHz 3 dB impedance is 6 ohms input power is 5 watts mini mum and 50 watts maximum and ef ficiency is rated at 87 dB at wattata distance of meter The Model SB10 offers an extend ed range 4 polypropylene driver that provides a frequency response of 90 Hzto ISkHz 5dB Nominal im Say You Saw It In Modern Electronics pedance is 8 ohms input power is 5 watts minimum and 45 watts maxi mum and efficiency is rated at 85 dB at 1 watt at a distance of meter Both speaker systems are available in black or white enclosures and hardware 300 Model SB30 150 Model SB10 CIRCLE NO 131 ON FREE INFORMATION CARD 60 MHz Oscilloscope Beckman Industrial s new Model 9106 three channel osci
110. e units or constants you want aren t available you can enter them by selecting Declare from the main menu Derive performs the majority of its math functions within a fraction of a second without the help of a co pro cessor which it will not use even if you have one Operations such as certain three dimensional plots however can take several minutes to complete Loading files from disk is also time consuming taking almost a minute to load a file with 40 entries Other features of the program in clude exact arithmetic to thousands of digits approximate arithmeticto a desired degree of accuracy and inte ger factoring A major drawback of Derive is the lack of a programming language or any way to do recursive calculations And there isn t any way to enter a range of values into an equation to get a range of results To get you up and running Derive has a 126 page user manual on line help arranged by topic and nine demo files The user manual is well Say You Saw It In Modern Electronics written and easy to understand but it could use more sample problems Comments amp Conclusions Derive which Soft Warehouse calls a mathematical assistant for your per sonal computer is a well rounded program that can perform many mathematical functions The menu system in general is easy to learn and use and the algebraic display is first rate except for the omission of subscripts Derive doesn t offer spe cific solu
111. eads into the circuit Be sure to keep this in mind when building the following circuits as well In Fig 6 is shown the circuitry of a transistorized filament lamp modulator driver that modulates a small No 243 or 222 lamp As in Fig 5 audio output transformer 7 connects to a small radio or amplifier The critical components are L1 and Ql If current through the collec tor emitter junction of Q2 is too high L may burn out or its life be excessively shortened Momentary surges may not harm Q2 but the average current through the transistor and L should not exceed 200 to 230 milliamperes You can measure the current through L1 by breaking the circuit at point X in Fig 6 and inserting an ammeter Current can be reduced by lowering the level of the signal applied to 7 or by inserting a current limiting resistor at Ry If Q2 becomes warm install a heat sink on its case For higher current operation use a power MOSFET for Q2 Self Contained Lamp Transmitter Figure 7 is the schematic diagram of a complete lightwave voice and tone light wave transmitter that uses a miniature No 222 lamp as a light source Transis tors Q and Q2 amplify the signal from the microphone and apply it to the modu lator driver circuit formed by transistors Q3 and Q4 Resistor R6 provides negative feedback to reduce the gain of the pream plifier formed by transistors Q and Q2 When S is closed the input preampli fier oscillates and c
112. ect for an ac outlet on one circuit to communicate with another on a different circuit using carrier Current transmission requires that the signal make a round trip via the step down transformer located somewhere in your neighborhood The solution for this is as simple as placing a 0 01 microfarad high volt age capacitor rated at 400 volts or greater directly across the 240 volt ac line somewhere in your home This capacitor can be installed at the outlet of any 240 volt ac appliance or at the breaker box or fuse panel where the 240 volt line enters your home A good choice for such a capa citor is the Radio Shack Cat No 272 160 Rated at 2 000 volts 2 kV it will easily handle permanent in stallation across a 240 volt ac line If you decide to install this capaci tor exercise extreme caution Bear firmly in mind that 240 volts ac is lethal Therefore before even at tempting to make any connections make sure to open the main breaker or remove the main fuse at the junc tion box to shut down all power with in your home so that you can work in complete safety As a further precau tion check the dead house wiring with an ac voltmeter prior to touch ing any house wiring This modification is recom Say You Saw It In Modern Electronics he mended by several manufacturers of carrier current controllers in their in stallation manuals and troubleshoot ing guides Although this should be looked
113. ed throughout the circuit as needed Resistor R2 and zener diode D4 Say You Saw It In Modern Electronics 101jU09 4 ssauly6ug o9 as Q u 2 N o e u Oa e o e z uj me N o9 Z 10000uF T iio no ape 4 2 wuraope4 7 PARTS LIST Semiconductors D1 D2 D3 IN4001 or similar 50 PIV ampere rectifier diode Socket 10 99lo1d 0 ejqe3 10 9npuo3 aaAly NEUTRAL 5V 0 D4 6 2 volt 0 4 watt zener diode da Ov wT zZ YNIIND NO 10193 01d O SLIDE FORWARD COMMON SLIDE REVERSE LIVE 9 e N 3 e 0 3 0 Q e W ud O e u Uy o Nm ze ze 3 28 OD o VO Qo oO z N o O uJ E e o c wm LL Oo a tO oe uu ET e e e e NID 9uey PHS w 5VO D5 D6 D7 1N4148 or similar switch ing diode LEDI LED2 LED3 T 1 light emit ting diode one each red yellow green 1C1 7805 fixed 5 volt regulator IC2 LM393 dual comparator IC3 CD4538B dual CMOS multivi brator 1C4 1C5 1C6 MOC3041 optical isola tor Q1 Q3 IRFS511 or any n channel power MOSFET Q2 Q4 Q5 SC150M or similar triac Capacitors C1 1 000 4F 10 volt electrolytic C2 1 zF 50 volt tantalum C3 C7 0 1 yF polyester C4 0 01 yF polyester C5 0 0056 F polyester C6 22 yuF 10 volt tantalum C8 10 yF 16 volt tantalum C9 4 yF 16 volt tantalum Resistors 4 wat
114. erall block diagram of the elements that make up the Programmer Say You Saw It In Modern Electronics 3 B is RS 232 compatible which makes it usable with just about every personal computer now in use MAX232 serial chip U4 contains two RS 232 drivers two RS 232 receivers and an on chip charge pump The charge pump uses the 5 volt dc sup ply line to generate the bipolar volt ages required by the RS 232 drivers Listed in Table 2 are the pinouts for the serial connector on the Pro grammer No handshaking controls are actively controlled by the Pro grammer and DTR is not connected and is thus ignored by the Pro grammer DSR and DCD are wired to the on condition or V at all times RTS is received buffered and looped back to the host at CTS which makes CTS track RTS Baud rate of the Programmer is se lected with jumper network JP2 while jumper JP permits selection of either modem 0 or printer 1 All standard rates from 300 to 9 600 baud are selectable with appropriate position of JP2 Shown schematically in Fig 3 C is the circuitry for the Parallel Printer Port Each data byte sent to the printer or in this case the Program mer is signaled by DST strobing low which sets the flip flop made up of U12C and U 2D This sets the BUSY line and latches the new data byte in to U11 The 68701 microcomputer chip in Fig 2 monitors the BUSY line P17 When it detects activity on this line it rea
115. erature made possible by the halogen cycle pro vides an exceptionally bright light source Moreover after 75 percent of its rated life a tungsten halogen lamp emits 90 percent of its initial light output The brilliant white light of a tungsten halogen lamp is accompanied by several drawbacks The envelope temperature of a tungsten halogen lamp must exceed 200 to 250 degrees C and may reach 350 de grees C This means ordinary glass enve lopes are unsuitable Instead fused silica quartz is required Special ceramic sockets are usually necessary and there may be restrictions on the operating ori entation of the lamp to prevent thermal damage to the lamp s seals Due to the high temperature required to fabricate fused silica envelopes halo gen lamps are more expensive than are conventional lamps They must never be Operated near combustible materials They must never be touched while in op eration Any fingerprints or other con tamination must be completely removed from the envelope before operation Fi nally the very high brightness of halogen lamps coupled with the ultraviolet that they emit makes them potentially haz ardous to unprotected eyes The filament of an incandescent lamp requires a finite rise time to reach its oper ating temperature after a current is ap plied Likewise the filament requires a Von FLASH RATE e 1 Hz Voo Q1 L1 SEE TEXT Fig 3 A simple CMOS lamp flasher
116. ercard Signature FOR OUR RECORDS DECLARATION OF AUTHORIZED USE i the undersigned do hereby declare under penalty of perjury that all products purchased now and in the future will only be used on cable TV systems with proper authorization trom local officials or cable company officials in accordance with all applicable federal and State laws FEDERAL AND VARIOUS STATE LAWS PROVIDE FOR SUBSTANTIAL CRIMINAL AND CIVIL PENALTIES FOR UNAUTHORIZED USE Copyright 1987 PACIFIC CABLE CO INC Dated Signed Pacific Cable Company Inc 7325 RESEDA BLVD DEPT ME RESEDA CA 91335 818 716 5914 No Collect Calls 818 716 5140 IMPORTANT WHEN CALLING FOR INFORMATION Please have the make and model of the equipment used in your area Thank You May 1990 MODERN ELECTRONICS 5 SERVICING RF PRODUCTS Signals picked up by the low capacity input of the Spectrum Probe allow rapid evaluation of problems Simply placing the probe near a component allows judgment of whether it is active RF failures are easily established 10dB per DIV 100 pM 100 MHz frequency A cordless phone base station is probed near its 38 970 crystal in fig 4 Both 39 MHz and its second harmonic are obvious The lowest line at 10 245 is also obvious and can be estab lished by probing the adjacent 10 2 crystal which then shows 10MHz as higher level than 38MHz We have established receiver RF oscillator system operation i
117. erence point for all signals and voltages in the 555 circuit both internal and external to the chip e TRIGGER pin 2 is normally held at a potential greater than 2 V 3 In this state 555 OUTPUT pin 3 is low If the TRIGGER pin is brought low to a potential that is less than V y 3 Ground V supply Trigger Discharge Output Threshold Reset Control voltage Fig 1 Package configuration and pinout details for the 555 timer OUTPUT pin 3 abruptly switches to the high state The output remains high as long as pin 2 is low but the output does not necessarily revert back to low immediately after pin 2 is brought high once again e OUTPUT pin 3 is capable of either sinking or sourcing current up to 200 milliamperes which is in contrast to other IC devices in which the outputs either sink or source current but not do both Whether the 555 output op erates as a sink or a source depends A on the configuration of the external load Figure 2 illustrates both types of operation The arrangement shown in Fig 2 A in which external load R is connected between the 555 output and V allows current to flow in the load only when pin 3 is low In this condition the external load is grounded through pin and small in ternal source resistance R In this arrangement the 555 output is a cur rent sink The circuit shown in Fig 2 B is for the case where the load is con nected between pin 3 of the 55
118. es you alert the program by first typing quotes You place a graph on the display by typing the sign MathCAD refers to each equation plot or block of text you enter as a re gion If after you have created an equation plot or block of text you don t like its placement on the screen you can move it the region by cutting it from one part of the screen and pasting it to another Say You Saw It In Modern Electronics FILTERING A NOISY SIGNAL WITH FFT Define the signal i 6 12 i i q sinj 14 cos 19 8 i 126 128 fdd some noise s q rnd 2 1 Fig 1 In MathCAD definition signs are often used instead of equal signs If you press F10 a horizontal menu is displayed across the top of the screen When you select a menu item such as System a drop down menu appears with several choices If you re working on an XT class ma chine the first thing you ll notice is how long it takes for the program to draw the menu box This is the first indication f how incredibly slow the program can operate at times Al though you can use the program on a dual disk IBM XT type machine you ll be much happier using it with the fastest machine and fastest hard disk you c n lay your hands on And throw in a math coprocessor for good measure If you press ESC rather than F10 a command iine appears instead of the horizontal menu Anything you can do with the menu you can do with the command line
119. even a business of your own in computer programming You master today s hottest computer languages gaining the skills you need to bulld programs for a wide variety of real world applications Send for your NRI catalog today It s yours free If the coupon is missing write to us at the NRI School of Computer Program ming McGraw Hill Continuing Educa tion Center 4401 Connecticut Avenue NW Washington DC 20008 IBM is a Registered Trademark of the IBM Corporation 5 ATP School of Computer npa McGraw Hill Continuing Education Center 4401 Connecticut Avenue NW Washington DC 20008 YES Please rush me my FREE catalog describing NRI s at home training in Computer Programming please print ul l l NEW PRODUCTS ity is rated at 100 mV rms from 2 kHz to 10 MHz and 200 mV from 2 MHz to 20 MHz Overload protection is to 500 volts ac and de The adapter attaches to any multi meter via banana plugs The user simply sets the multimeter to the 200 mV dc range and selects the frequen cy range to be measured via a rotary switch on the converter module The supplied test leads then plug into ba nana jacks on the adapter and are used in the normal manner The only other control on the converter is a HI LO TRIG LEVEL slide switch Sepa rate POWER and LO BAT Indicators are provided The converter measures 3 6 x 2 8 x 1 6
120. g File contains the address and bytes assembled for each line of input followed by the original source code The SI9 Output File is an ASCII representation of the binary file that will be programmed into the EPROM on board the 68701 SIIAF8000F8EOOFF7F000086FF97049705960297064397077EF80D7D Say You Saw It In Modern Electronics S113FFFOF800F800F800F800F800F800F800F8003D 89030000FC EPROM of the 68701 to determine if it is completely erased If so the chip is ready to be programmed and the green ERASE LED turns on The programmer now waits for you to send it an object file via either the Parallel or the Serial Port The object file must be in the Motorola standard S19 format Any assembler for the 6801 03 microprocessor will generate this type of output As the object fileis sent to the Pro grammer it is converted to binary format on the fly and is stored in the RAM buffer If an error occurs dur ing conversion such as a non hex character or bad checksum the red LOAD FAIL LED turns on Once the object file is loaded the internal EPROM can be programmed Successful completion of the pro gramming step is indicated by an on green PROGRAM OKAY LED The last step in the procedure is to verify that the programmed EPROM May 1990 MODERN ELECTRONICS 33 Ul 14 7 U2 13 3 U3 16 8 U4 16 15 US 28 14 U6 28 14 U7 16 8 U8 7 21 l U9 20 10 U10 20 10 U11 20 10 U12 14 7 02 1N5819 voc ee sl
121. ge Visual indication of a received sig nal is provided by light emitting di ode D3 The output signal from U2 is passed to current limiting resistor R7 to drive the base of switching transis tor Q2 This causes a current to flow through the emitter collector junc tion of Q2 and forward biases the LED Current for D3 is provided by R8 C4 Capacitor C4 maintains a high current at the anode of D3 while preventing excessive dropouts and spikes from appearing on the 8 volt dc power supply during the LED turn on and turn off cycles These on off cycles appear at the same rate and frequency as that of the received signal This indication can be used in conjunction with the manual gain control to provide for a quick visual reference of receiver gain setting during initial installation of the receiver module To communicate with the device s to be controlled the received control signal must be reconstructed and out put in its original IR energy To ac X9f Fig 9 Actual size etching and drilling guide for receiver printed circuit board complish this the shared output of U2 is passed to the IR output driver This output is capacitively coupled by C5 This ac coupling provides overdrive protection for Q3 and the power supply should the manual gain be set high enough to force the out put of U2 into a continually on steady dc state
122. geable cells 149 95 Model SR 901 189 95 Model SR11 CIRCLE NO 128 ON FREE INFORMATION CARD IR Remote Controller For Amiga Computers Edu Vid Research s Pembina ND IR Remote Controller is primarily a hardware package for use with Com modore Amiga personal computers A model for use with IBM and com patible computers is soon to be avail able It allows a VCR or any other infrared remote controlled device to be operated by a user s program The Controller can learn the IR pulse codes from the remotes of most de vices It can also detect when a VCR is actually sending a video signal and with suitable monitors can switch the screen from computer output to video output In addition touch tones can be placed on a video tape for the Controller to de tect and its program do various things These include mix the Amiga s sound or voice with the vid eo sound or overlay computer output on the video output if a separate Genlock is used or simply stop the video while the computer outputs to the monitor screen Software provided with the pack age is intended to demonstrate the product s many uses Meant mainly for people who program in BASIC ri 1 ji z T Pd i assembler or C to produce applica tion programs the IR Remote Con troller comes with a cable to connect it to the parallel printer port of an Amiga 500 or 2000 the Amiga 1000 requires an optional adapter two cables for connection
123. h the input resistor shown this corresponds to 7 5 V The control summer adds voltages from various control sources such as the fc panel control transient generator Ifo etc Any number of signals can be summed by applying them through resistors to the summing node of the op amp Frequency offset adjust is required in polyphonic SIG IN 68K Q CONTROL 13K 47K 8200 Q 01 ut OUT v TLOB2 nY 470K TEL LABS TYPE Q81 TC 3600 pom C OPTIONAL SEE BELOW 50K ALL COMPONENTS 5 UNLESS NOTED FREQ OFFSET ADJ and programmable systems to make the filter s sound the same for an identical input control voltage For best control re jection the control summer and input at tenuator should be designed so that maxi mum swing at the 2044 control pin cor responds to extremes of the intended sweep range when the control summer is driven to the supplies With the values shown one will obtain 90 mV at the in put pin which corresponds to a 1000 to 1 sweep range for 15 V supplies The V octave trim and the Tel Labs temperature compensating resistor are required in applications where the filter has to produce accurate musical intervals when in oscillation If this is not neces sary the control op amp feedback net work and the Tel Labs resistor can be re placed by 1 300K and 1K ohm resis tors respectively The SSM 2044 is a 24 dB low pass filter with a 10 000 to 1 variable cutoff frequency Cutoff frequen
124. he lamp to be adjusted for optimum operation without zapping the lamp Lamp Modulators Figure 5 shows the circuitry for an ultra simple transformer lamp modulator based on circuits published nearly 50 years ago You can assemble this circuit in just min utes The simple receiver in Fig 4 will re ceive the signal from this circuit For ini tial tests you can use a radio as an audio source or replace the radio with a small amplifier to transmit your voice While the low impedance output from most transistor radios and amplifiers can be coupled into the 1 000 ohm 1k wind ing of the audio transformer in the Fig 5 circuit much better results can be ob tained if you connect a second transform er to the first Connect together the 1 000 ohm winding of the two transformers Then connect the 8 ohm winding of the new transformer to the output of the ra dio or amplifier You can control the brightness of the lamp by inserting a low resistance rheo stat in series with the lamp and B It s much simpler however to achieve the same effect by altering the volume of the amplifier or radio In either case it s im portant to keep peak current through the filament well below the point at which the filament melts Speaking of melted lamp filaments chances are you will blow some lamps while experimenting with them in modu lation circuits Therefore it s always a good idea to install lamps in sockets rather than soldering their l
125. high With the first negative going pulse from pin 1 of C2B at pin 4 of C3B through D7 C8 immediately dis charges through D7 Further pulses keep the capacitor discharged With C3B configured so that it will trigger only on a rising input the output at pin 6 remains low and will not trigger to a high state until C8 is again per mitted to fully recharge Full recharging of C8 does not oc cur urtil the projector lamp fader has been returned to its fully faded out position Only then will C8 recharge through R76 As the potential across C8 rises through the input threshold of C3B the output pulse begins The slight delay before the output pulse goes high allows the projector lamp to becompletely out sothat changing of the slide will not be seen on screen Use of optical isolator C5 and tri ac Q4 permits the slide forward re verse connections in the projector to be made without having to use a re lay The slide change mechanism ad vances the slide tray by one In summary as the fader is first operated the projector switches on and the lamp is brightened to full When the slide is no longer required the fader completely fades out the lamp in the projector at which time the slide changes and the projector switches itself off Spurious spikes are prevented from falsely triggering C3A by R6 and C5 in the projector switch on cir cuit Decoupling by C7 helps in pre venting similar false triggering This latter capaci
126. how many times haa 7 ZEE you ve failed before Resul s guaranteed when BARGAIN HEADQUARTERS you follow the instructions PASS Publish CABLE TV DESCRAMBLERS gt mpina tee ale ing s CW Mental Block Buster program helps Oek M35B ONLY 60 you explode mental blocks that hold you back 6 month warranty We ship C O D Based on 40 years of research the CW Mental 6805 MICROCOMPUTER VoWest P eee Block Buster uses guided meditation dynamic DEVELOPMENT SYSTEM Global Cable Network visualizations and powerful affirmations to Now its easier than ever to incorporate single chip lecce x blast through mental blocks You can do microcomputers in your new designs The MCPM 1 system allows the IBM PC and compatibles to be used as a complete development system for the code That means new bands more contacts more fun This is not a CW practice tape ORDER TODAY 800 327 8544 Motorola MC68705P3 P5 U3 US R3 and R5 single CIRCLE NO 159 ON FREE INFORMATION CARD The CW Mental Block Buster audio cassette chip microcomputers The system includes a cross and practice booklet are only 24 95 ppd in assembler program a simulator debugger program the US NY residents add 1 87 sales tax and a programming board that connects to a serial Cable Converters And Quantity discounts available for classes port Price 449 00 VISA and MASTERCARD PASS Publishing P O Box 570 Stony accepted TECI ENGINEERS ECR co
127. ichever method of construc tion you use it is a good idea to use sockets for all DIP ICs and a ZIF zero insertion force socket for U8 Home fabrication of the double sided printed circuit board for the project is not recommended as prac tical because of the need for plating through the holes that interconnect conductors located on both sides of the board The ready to wire pc board from the kit supplier has plated through holes and is silk screened on the component side for Say You Saw It In Modern Electronics Pin Circuit Description Direction CF Carrier Detect DCD From Programmer 2 BH Receive Data RD From Programmer 3 BA Transmit Data TD To Programmer 4 CD Data Terminal Ready DTR No Connection 5 AB Signal Ground SG N A 6 CC Data Set Ready DSR From Programmer 7 CA Request To Send RTS To Programmer i CB Clear To Send CTS From Programmer iy CE Ring Indicator Rl No Connection easy component installation Assuming you are using the pc board start wiring it by installing the sockets for the ICs If you go the Wire Wrap route arrange and orient the components as near to the layout shown in the photo at the beginning of this article Whichever method of construction you use however do not plug the ICs into the sockets until after you have conducted preliminary voltage checks and are satisfied that the project has been properly wired Semiconductors D1 D2 1N5819 diode LED thru LED4 Green
128. ide switch off control circuit The proj ect does not require any modification of the projector itself and is relatively easy to build using readily available components and materials About the Circuit Shown in Fig 1 is the schematic dia gram for the entire Controller cir cuitry The fade in fade out dimmer portion of the circuit is composed of both comparators in C2 optical iso lator C6 the last stage shown in Fig 2 A and each stage s associated components Note also that the 117 volt ac line driven dc power supply for the entire project precedes the dimmer circuit The fader circuit was designed around the LM393 dual voltage com parator specified for C2 This par ticular chip is designed to operate from a single ended dc power supply In Fig 1 operation of the dimmer circuit is as follows The low voltage ac output from power transformer T1 is passed through rectifier diodes D1 and D2 to emerge as half wave pulsating dc Resistor R is included in the circuit to assure that enough 36 MODERN ELECTRONICS May 1990 current flows to switch the diodes fully on Diode D3 isolates point A the junction of the three diodes from the smoothed dc produced by the filter ing action of C at point B so that the potential at the IN terminal of regulator C is approximately 8 volts At the OUT terminal of C point C the potential is a regulated 5 volts which is further filtered by C2 and distribut
129. iginal circuit when Q and Q conduct current flows through D1 Q and D2 Conversely when the top line is negative no current flows in the original circuit current still flows through D3 Q and D4 thus seizing the phone line and causing a busy signal to be received by a caller on that line Thomas M Kiehl Largo FL e We have two telephone lines and one answering machine in my home We ve looked in the past for a device that would enable us to have the answering machine pick up either line to no avail I gave up looking for a solution long ago Then the Two Line Telephone Answering Ma chine Interface that appeared in the February 1990 issue came along to solve the problem However while building the project I discovered two errors One is that mention of C4 and R9 was omitted from the Parts List The other is that J1 and P2 on the wiring guide were trans posed Unless thisis corrected phone line voltage from Line 2 will be fed into Line 1 Thanks for an interesting solution to my problem Keep the useful projects coming Kevin Fodor Akron OH LD Say You Saw It In Modern Electronics MCM ELECTRONICS FALL CATALOG 1989 MCM ELECTRONICS 650 CONGRESS PARK OR CENTERVILLE OH 45459 4072 A PREMIER Company See A Bright Future For You If you had a crystal ball you could gaze into it and immediately see why MCM should be your electronic parts and components supplier Here are a few
130. ime studying a hefty manual If you are experienced with scienti fic calculators and want to upgrade to a more powerful model the HP 48SX is certainly an excellent choice But if you are a novice in this area the choice is not so clear cut If you need a scientific calculator as sophis ticated as this one be prepared to spend many hours of often frustrat ing time learning to harness its pow er If you need the functionality of the unit but not the frustration you might be better off considering math software for the PC that meets your needs but is easier to learn ME 555 Timers from page 57 The two configurations shown in Fig 9 are for current source and cur rent sink operation just as in the case for the LEDs above Make sure that you use only one of these in a given circuit of course Note in Fig 9 that each relay coil is shunted with a 1N4007 rectifier di ode Diodes are used for spike sup pression when the relay coil is de en ergized The back emf generated when a relay coil deenergizes can be a high voltage spike that can destroy the 555 and other components in a circuit It has a reverse polarity with respect to V Thus the diodes are normally reverse biased except when a large inductive spike from the relay is received Keep firmly in mind that these diodes are not optional Shown in Fig 10 is a method for solving a problem that is sometimes encountered with 555 relay drivers and certain other 555
131. imum bench space The hand piece itself is light A wide range of high mass soldering tips are available for the Model SA 570 86 90 CIRCLE NO 122 ON FREE INFORMATION CARD Video Surround Sound Panasonic s Model SY DSI digital signal sound processor is said to give Surround sound style audio effects to home video systems without the need 80286 Based Laptop Radio Shack s Tandy 2800 HD lap top computer is built around a low power 80C286 microprocessor oper ating at a user selectable 6 or 12 MHz Housed in an executive black case the 2800 HD features a 9 x 8 inch full size electrolumi nescent back lit EGA compatible su pertwist liquid crystal display with 640 x 400 pixel resolution and 16 gray scales an enhanced 84 key key board with true 101 key emulation mode and standard 3 5 mm key stroke and the ability to exchange batteries without turning off the sys tem Storage capacity is 1 MB of user RAM expandable to 2 MB an in ternal 20 MB hard disk drive with 29 ms access time and one 1 44 MB 3 5 inch floppy disk drive Ports available include EGA CGA compatible external video bi directional parallel and RS 232C ser ial A socket is provided for an 80C287 numeric coprocessor Bun dled with the system and installed on the hard drive are Tandy s Desk Mate Version 3 3 productivity software MS DOS 3 3 and TEMM LIM 4 0 An internal replaceable recharge able gel type lead acid b
132. in a table create a two dimensional plot or both Math CAD can also create surface plots such as the one shown in Fig 2 To create a Surface plot you must specify a range of values for two vari ables Once you create a plot you can size rotate or tilt it hide lines and change the vertical scale Besides entering a range of values from the keyboard you can also enter values stored on disk in an ASCII file This is about as close as you can come in MathCAD to executing a program loop Other programming like fea tures let you issue a set of commands stored in a text file or use an IF func tion and relational operators to test a condition and change the behavior of an expression based on that condition MathCAD has built in units for mass length time and charge To at tach a unit to a number you simply multiply the two together You can The MathCAD Electrical Engineering Applications Pack consists of a disk with 19 applications files a file of units definitions sample data files and a 120 page user s guide The applications carry out common design calculations from several different branches of elec trical engineering and employ Math CAD s complex arithmetic matrix op erators equation solving and plotting capabilities Topics covered in the ap plications pack include antennas and waveguides circuit analysis transmis sion lines filters coding and signal pro cessing and transfer functions for con t
133. ions in all Get it from EduCALC vwe re the world s foremost deep discount dealer O Eze Dee 274 Discount HP 48S X for HP calculators since 1976 We have yours in stock ready to ship quickly Plus you ll have our 15 day money back guarantee Stock HP48SX Sci Expandable Calculator List 350 274 95 IR Il Stock 82208A PC Serial Interface Kit List 59 95 erre 49 95 pur Stock 82209A MAC Serial Interface Kit List 59 95 49 95 geet Stock 482211A Equation Library ROM Crd List 100 79 95 Stock 82214A 32K RAM Card List 80 69 95 Stock 82215A 128K RAM Card List 250 194 95 Stock 82240B Portable Infrared Printer List 135 115 95 Toll free credit card orders M F 8 to 5 west coast time 800 677 7001 or l all hours all days 800 633 2252 ext 359 FAX orders to 714 582 1445 Or just tear out this ad and mail it with oH name address and check UPS 4 per order to EduCALC 27953 Cabot Road Laguna Niguel CA 92677 ELECTRON TUBES BUILD YOUR OWN LAS OVER 3000 TYPES IN STOCK New manual reveals latest laser break throughs and gives complete step by step ir trucions for bulking 6 kinds of real working lasers with easy to get parts sources for all parts are given including an infrared laser that you can make quickly for under 30 30 Day Money Back Guarantee if not com
134. ke LENG AREA VOL TIME SPEED and MASS To see more menu Items you press the Nxt key Many menu words have alittle bar on top of them to indicate that a sub menu ex One of the options available for the HP 48SX scientific expandable calculator is a serial interface kit Although the kit was not available to Modern Electron ics for a hands on review at press time we can give you some information about it The kit comes with a serial ca ble and data communications software on 3 5 and 5 25 inch disks The cable and software link the HP 48SX to IBM PC and compatible computers and Ap ple Macintosh computers To access the serial port from the HP 48S X there is an 1 O key that brings up acommunications menu on the display The menu has the following choices SEND RECV SERVE KGET FINIS SETUP The only one of these choices that has a sub menu is SETUP This menu lets you configure the I O port for wireor infra red transmission and ASCII or binary transmission It also allows you to select a baud rate between 1 200 and 9 600 bps set the parity set the checksum type and set the translate code When you press the NXT key five more menu choices appear RECN PKT KERR OPENI CLOSE Another press of the NXT key reveals five additional menu choices XMIT SRECV STIME SBRK BUFLE In general these commands allow the HP 48SX to send and receive files with a ists for that menu For example if you choose AREA a menu appears
135. lifier characteristics and Nyquist diagrams However the program it self doesn t permit the user to do any plotting or printing Comments amp Conclusions CMPCALC4 is a specialized tool that can help you deal effectively with complex numbers The program has several limitations it s true namely the user interface an exclu sive use of scientific notation and lack of printed output But CMPCALCA is easy enough to learn and use with the help of the manual and contains enough features to enable you to perform calculations and create automated procedures Thus if you work with complex numbers all the time and don t havea Satisfactory tool to deal with them CMPCALC4 is a good low cost choice for the job N cM G 3 H P s Newest Scientific Calculator or electronics engineers tech nicians educators and stu dents involved in electronics a scientific calculator is an indispen sable tool for solving problems These calculators have been around for many years but it seems that each time a new model appears it has more features than any preceding it This is just the case with the HP 48SX the newest entry from Hewlett Packard a company known for its leadership position in this field In fact the HP 48SX combines the best features found in two earlier Hewlett Pack ard products It has the calculation and graphics capabilities of the HP 28S and the flexibility and expand ability of the HP 41 The
136. light emit ting diode LEDS thru LED7 Red light emitting diode Q1 Q2 2N3904 silicon npn transistor Q3 2N3906 silicon pnp transistor U1 74HC14 U2 78S40 U3 HC4040 U4 MAX232 US 6264 U6 2764 64K EPROM U7 74LS138 U8 MC68701 single chip micro computer U9 74HCT573 U10 U11 74LS374 U12 74LS00 Capacitors C1 C2 C5 C6 C7 0 l F ceramic disc C3 22uF 50 volt radial lead elec trolytic Say You Saw It In Modern Electronics Once the sockets are mounted in place proceed with installation of the resistors capacitors crystal and jumper pins Make certain that the electrolytic capacitors are properly polarized before soldering their leads into place Continue wiring the board with installation of the LEDs and transistors Again make certain that the LEDs are properly oriented and the leads of the transistors go in to the proper holes before soldering any pins into place PARTS LIST C4 680 pF ceramic disc C8 thru CI2 10 uF 16 volt radial ead electrolytic C13 C14 20 pF ceramic disc C15 0 01 pF ceramic disc Resistors 4 watt 5 tolerance R1 thru R4 1 500 ohms R5 R6 6 800 ohms R7 R11 100 000 ohms R9 130 ohms R12 4 700 ohms R13 0 62 ohm RI4 R15 1 100 ohms R16 100 ohms R8 270 ohms watt R10 1 000 ohm inch pc mount trimmer potentiometer RNI RN3 RN4 4 700 ohm eight pin SIP resistor network with pin 1 common RN2 220 ohm eight
137. list send 19 95 to RICH CONSULTING Box 8206 Fort Wayne IN 46898 8206 PLANS PLASMA GLOBE 5 LAMP SAV ER 5 COMMUTER LECTRICKAR 15 Alt 20 Robert Bucy ME Box 28794 Dallas Texas 75228 NEW aquarium heater design ends RFI and sticking contacts Send stamp for info Two Fox Electrix POB 721 Pawling NY 12564 0721 SURVEILLANCE COUNTERSURVEIL LANCE devices catalog Cameras bug detec tors video camera detectors transmitters communications and much more Catalog 3 00 DSP P O Box 1275 ME Redondo Beach CA 90278 TUBES New up to 90 off S A S E Ker by 298 West Carmel Drive Carmel IN 46032 KINETIKITS from KINETICO electronic kits outputting light or sound Free catalog KINETICO P O Box 1634 NY NY 10114 0508 MINIATURE Electronics like James Bond Catalog 3 00 refundable F amp P Enterprises Box 51272 Palo Alto Calif 94303 H DETECTION Surveillance Debugging Plans Kits Assembled Devices Latest High Tech Catalog 5 DETECTION SYSTEMS 2515 E Thomas 6 864H Phoenix Ari zona 85016 ELECTRONICS COMPUTER Manuals Software Hardware Services HIGH VOLT AGE DEVICES SECRET SURVIVAL RADIO PHONE COLOR BOXES ELECTROMAGNETIC BRAINBLASTER RADIONICS DISK SERVICE MAN UAL COMPUTER PHREAKING ROBOFONE ULTIMATE SOFT WARE PROTECTION Many More Cata log 2 CONSUMERTRONICS 2011 Cres cent Alamogordo NM 88310 505 434 0234
138. lloscope of fers a 60 MHz bandwidth and the ability to display eight traces on screen Its third channel provides a Continued on page 82 HITACHI SCOPES AT DISCOUNT PRICES Digital Storage Scopes VC 8025 20MS S 2K word Memory Capacity 2349 00 Advanced Storage functions create new dimensions in scopes such as one shot observation l icker tree display baght display tor even high speed event trace observation for low speed event tard copy by plotier and data out put 10 computer VC 6045 100MtHz 408IS S 4K word Memory cap cail All Hitachi COpes inchade probes schematics and Hitachi s 3 year wortdw de waranty on parts and labor Many acces Sones availabie for ali scopes 40M 40MHz 40MH2 60MH2 100MHz 100MHz 150MHz 20MHz iz Duel Trace Oscilloscope 375 M0 1251 6 CRT Bullt in TV Sync 1a joi evt 2v L 4 FREE DMM component tester P 1 65M 1x 10x SCOPE PROBES 1995 P 2 100MHz 1x 101 23 95 DC to 100MHz Dual Channel Delayed Sweep CRT Readout Sweep Time Autoranging Save 170 Trigger Lock DC to 20MHz V 1060 2mV Sensitivit Dua Channel List 1595 1 359 il V 212 425 List 595 1mV sens DC Ottset Vert Mode Tngger An Mag T 1mV sens Delayed Sweep DC Offset An Mag 1mV sens DC Ottset CRT Readout Cursor Meas 2mV sens Delayed Sweep CAT Readout 2mV sens Delayed Sweep CRT Headout Cursor Meas 1mV sans Delayed Swee
139. me Caveats When you are setting up the Ex tended Play or any carrier current system for permanent use there are several things to watch for One is ca ble TV converter box IR remote con trol systems Although the majority of these systems are well designed some are poorly designed with regard to method of IR transmission A very few converters the type distributed by some cable TV franchises use an unmodulated IR signal to transmit the control codes In affect these systems simply use slow on off pulses that make them susceptible to false signals and may or may not be accurately retransmitted by the Ex tended Play system High noise levels may appear on the ac power lines used to carry the Extended Play signals Although this Say You Saw It In Modern Electronics is not a Significant problem it ap pears at the receiver as a constant dim glowing of the LED indicator You can tackle the problem by modi fying the transmitter or and receiver as described above to deal with this problem A final consideration is the house wiring itself Because of the manner in which the incoming 240 volts ac is divided into its two respective 117 volt ac legs it is possible for two outlets in the same room to be on completely different circuits each 180 degrees out of phase with the other with respect to neutral This single anomaly in the house wiring is the biggest hurdle to be overcome by any Carrier Current system In eff
140. mote TV receiver be forehand to be sure it is playing whatever is recorded on the tape Place the Extended Play transmit ter onor nearthe remote TV receiver Using the remote control transmitter supplied with the VCR press PAUSE not being ableto see the VCR indica tor lights may take some getting used to if you have never used a remote re mote control system before If you correctly assembled the Extended Play transmitter and receiver mod ules and your house wiring provides good coupling the TV image dis played on the TV receiver screen should freeze to a still picture This simple test verifies that the system is indeed operating as it should If you wish you can resume picture action stop it fast forward or rewind to another section of the tape to check out these functions as well However if even one function works via the Extended Play link all other functions will as well If your VCR does not respond pro perly during the system operational check something is wrong with the wiring in either the transmitter or the receiver module or both In this event power down both units and carefully check over your work If you have a problem and use an oscilloscope to perform any tests in the Extended Play circuits do not make any connections to ground If ee aA Re Ec Fig 13 Photo shows fully wired transmitter left and receiver right circuit board assemblies just prior to installation in the enclosures at
141. moves this entry to the work area it displays a standard integral sign Or if you want to enter a variable raised to a 20 MODERN ELECTRONICS May 1990 power such as x you enter it as x 2 at the menu prompt the program displays the variable with a super script in the algebra window One thing the program does not do how ever is display subscripts The algebra window remains in ef fect until you choose Plot from the menu Then the work area changes to a plot window One of the slick fea tures of the program is its ability to open several windows and mix alge bra and plot windows on the screen at the same time as shown in Fig 3 To do this you choose Window from the main menu Though most operations are easily accessed from the main menu some are inexplicably hidden away in sub menus For example once you enter an expression it s likely that you ll want to evaluate it at some point To do this however you have to figure out that the Substitute command is in the sub menu of the Manage com mand not very intuitive Or some times the program will give you an answer like 4 If you want the deci mal form of the answer you have to scout through the menus to find Deci mal as part of a sub menu of Notation which is part of a sub menu of Options Although you can enter explana tory text and text expressions in for mulas it is not readily apparent how to do so You must choose Word from a third level menu
142. n taining a silk screened double sided pc board with plated through holes and solder mask programmed 2764 EPROM and documentation diskette in 360K IBM for mat is available for 35 from Lucid Inc P O Box 292 Mary Esther FL 32569 Flo rida residents please add state sales tax All other components are available from local suppliers and mail order houses 00 EMERE Se a ee ie ee Se SS ee SS Sa ae May 1990 MODERN ELECTRONICS 27 RN2 220 3338333 vcCo ISP O F K Gc A m CDE 71 gt A f I rR Y L 6 T ni IIl a eS E RASED QO DO i lt gt a 2 D2 I 6 58 B a3 03 tye BE LEDS cs be S sum LOAD 196 06 H8 51 PROGRAM MEMM C Sck LED LEO VERIFY c pr A ALL CAPOCITORS ON THIS PAGE ARE iOuFd AT 16V g a Fz a A2 ERE D m S lt PEz d os RET LJ a Peal pece R4 OC g a D ee va JP1 a P LE O SHORTED MODEM 1 OPEN PRINTER 68701 Baud Clock Pin P22 Baudrate 76800 9600 38400 4000 19200 2400 9600 1200 B 4800 600 2400 300 28 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics J3 CENTRONICS PARALLEL INPUT VCC O C DEO e 5 ee ee 6 pA or 2 Ip P un LI 5 Bape 131 D BR aw i meenen o ae A B 18 D4 ay 7o IP M oe Hii HE 7 i q oc LX SESK Pin Faz gt
143. n Modern Electronics will be projected onto the wall when the filament is at the focal point of the lens This simple demonstration shows that a small fraction of the light emitted by a fil ament can be collected and collimated in to a narrow beam You can make your own lens collima tor or use binoculars or a small telescope My son Eric and I have placed a small lamp at a telescope eyepiece and project ed an image of the filament on a building more than a hundred meters distant We then sent voice and music signals over the collimated beam to a receiver Since only a tiny fraction of an incan descent lamp can be collected by a lens a reflector provides a more efficient means for collimating light from a lamp A las er Of course provides a much better source of collimated light But flasl light lamps and simple lenses are very inexpen sive and with them flashing signals mu sic and voice can be sent a fair distance on a dark night You may wish to do as I ve done and assemble filament lamp transmitters and receivers inside plastic 6 volt lantern light housings These large flashlights are equipped with reflectors and plenty of space for circuits and batteries ME Y BLACKS DECKER DELUXE WIRELESS SECURITY SYSTEM Intelligent home security system Detects intruder during entry Wireless for easy installation Difficult to defeat because of new advanced technology Lamp command flashes lamp upo
144. n dvesa dau Tul Services nm nena ho oe 134 FECI iu aia wpe ee 166 Tech Serv sisoosss TARRE F Trans World Cable Co UEM U S Consumer i se ea a eee 156 Ucando vacas LN Video Link Ent Inc i Wi 157 Viejo Publications TESA Ei Visitect Inc We d like to see your company listed here too Contact Jonathan Kummer at 516 681 2922 to work out ap advertising program tailored to suit your needs Free Product Information Readers can obtain free information on products advertised by the above com panies as well as for some editorially mentioned products Simply circle the appropriate number printed below an advertisement onto the Modern Elec tronics Free Information Service card bound into this issue After filling in your name and address just mail the postpaid card Your request will be for warded directly to the advertiser with a mailing label prepared by our reader service department to ensure speedy re sponse from page 15 means for monitoring the waveform of an external sync signal A multi turn time control permits simple waveform expansion Dual adjustment for both coarse and fine control are combined in a single knob Also included are triggered sweep circuitry for stable on screen displays and variable hold off con trol for proper triggering on com plex waveform signals Features include A and B sweeps with delayed sweep and segme
145. n equation Logically you expect to be able to do something with it such as plot it If you try to plot it by press ing the orange arrow and Plot keys you get an error beep To actually plot the equation you have to enter it on the stack first by pressing Enter then press Plot then press STEQ store equation on the menu bar then press PLOTR plot pa rameters on the menu bar and then press DRAW on the menu bar And this is just one way of doing it Suffice it to say that advanced op erations performed on the HP 48SX require a lot of keystrokes And any time you are in the equation mode or the plot mode the calculator takes some time to do its work For exam ple it takes 15 seconds to draw the plot for y x It s possible to draw diagrams with the HP 48SX The way to do this is to press the orange arrow and Plot keys and select PLOTR and ERASE from the menu bar Then you press the orange arrow and Graph keys This brings you to a blank screen You then press the Nxt key to access the drawing menu This menu bar has commands such as DOT DOT LINE BOX and CIRCL You use these commands in Say You Saw It In Modern Electronics O E ae TASS SRS eee ee he ei a eS SS SSS SS AN conjunction with the cursor keys to draw pictures A drawing done this way is shown in Fig 2 To do unit conversions on the HP 48SX you press the orange arrow and Units keys This brings up the units menu The menu displays words li
146. n intrusion Signal relay relays entry sensor intrusion Signal from a remote area of your home to controller Tamper resistant a 85 decibel alarm on inside siren Piercing 120 decibel outside siren Fail safe battery back up Low battery warning 2 Year Warranty includes 8 entry sensors 1 system controller includes inside siren 1 Signal relay 1 lamp command 1 outside Siren 2 window stickers 1 yard sign and complete hardware and batteries RY PERFECT l FACTORY NEW FACTO FACTOR ET Due to a special ar rangement we were able to obtain a large inventory of 698 00 these wireless se curity systems As a result we can now offer them to 99 you at HUGE SAV INGS Item No B 1984 133389 Insured Ship Hand 15 00 FOR FASTEST SERVICE CALL TOLL FREE 1 800 729 9000 MasterCard pie DAMARK INTERNATIONAL INC 6707 Shingle Creek Parkway Minneapolis MN 55430 Customer Service 612 566 4940 Manufacturer s Suggested Retail Please rush me Black amp Decker Security System s 299 99 each plus 15 00 s h each Item No B 1984 133389 MN res add 6 sales tax Name Address City State Zip CO Check MO O VISA CO Master Card CO Discover DELIVERY TO 48 U S STATES ONLY Bil SOLID STATE DEVICES I Filters FIFOs and other Devices L By Joseph Desposito This month we ll take a look at several types of a
147. n seconds with no connection information schematic etc 10dB per DIV frequency 100 MHz 100 MHz When the transmitter is activated by pressing CALL probing near the 15 537 crystal pro vides fig 5 Fundamental operation and many harmonics are shown As the probe is placed near the following stages the fundamental is decreased and the third accentuated until the relatively clean output of fig 6 is obtained near the antenna lead The transmitter RF is visible in seconds 107 SPECTRUM PROBE converts any scope into a 100MHz spectrum analyzer frequency 1 99 direct Smith Design 1324 Harris Rd Dresher PA 19025 215 643 6340 CIRCLE NO 16 ON FREE INFORMATION CARD W EDITORIAL Thanks for the Memories We worry about U S dependence on for eign oil on foreign minerals such as chromium and so on There isn t too much one can do about materials that we don t have on our shores of course But production and quality of products that aren t dependent upon access to raw ma terials is another story So we also worry about our declining automobile industry our disappearing shoe industry our withering clothing industry and our beaten down industrial machinery busi nesses What to do Kawasaki Yamaha and Honda among others caused much consternation a few years ago when their hold on the motor cycle industry appeared to be unbreak able Harley Davidson a subsidiary of AME and the last basti
148. n the en closure and again use a large plastic cable tie to provide strain relief Plug the conductors into the appropriate holes in the small circuit board as sembly observe the same color cod ing used for the connections to the main circuit board assembly and solder each into place The seven pin molded plug and 36 inches of seven conductor cable re quired for connection from the small branching box to the slide projector can be obtained from Kodak see Note at end of Parts List All you need do to wire this into the circuit is to prepare its unfinished end as de scribed above for the control cable Pass this end into the enclosure through its grommet lined hole use a Live On Live In large plastic cable tie strain relief and wire it to the small circuit board as sembly as detailed in Fig 2 A less expensive solution is to use two plugs both available from your local Radio Shack store Cat No 270 041A is a round five pin plug that fits into the top section of the socket on the projector and Cat No 270 017 is a multiple pin plug that can be machined to fit a number of formats including the two pin for mat on the projector If you go the less expensive route you must fabricate the cable assem bly yourself Thisis simple enough to accomplish using the details given in Fig 2 for wiring the cableto both the circuit board assembly and the con nectors Exercise care when fitting the small
149. nalog and digital devices The analog devices are a voltage controlled filter oscillator a low noise filter and quad and dual low power operational amplifiers The digital devices are an 80C52 BASIC processor and a family of bidirectional FIFOs Analog Devices A Voltage Controlled Filter Oscillator As an alternative to switched capacitor filters Precision Monolithics Inc 1500 Space Park Dr P O Box 58020 Santa Clara CA 95052 makes a four pole volt age controlled filter oscillator This product the SSM 2044 offers a 1 MHz bandwidth and is appropriate for a wide range of applications including medical imaging ultra sound and instrumenta tion systems However the design of the SSM 2044 has been optimized for use as an electronic music low pass filter A typical connection is shown in Fig 1 In Fig 1 the SSM 2044 is connected as a four pole low pass electronic music fil ter The differential signal inputs will ac cept any signals up to 18 V peak to peak If two oscillators are used in a voice the output of the second should go to the opposite filter input from the first with a 3 dB signal level difference This can be accomplished by scaling the input attenuators as shown thus preventing cancellation as the oscillators phase with each other The sense of the Q control is from GND up with minimum resonance at GND Oscillation will occur when the current into the Q pin reaches approxi mately 425 pA Wit
150. nd equipment Send 3 00 in a chek or money order or call 1 800 543 3568 today and use your Mastercard or Visa Coneolidated Electronice Incorporated 705 Watervliet Ave Dayton Ohio 45420 2599 Name Addreaa City CIRCLE NO 147 ON FREE INFORMATION CARD NEW PRODUCTS sity can be adjusted depending on the source and according to taste Most four speaker arrangements have a small hot spot in which the surround sound effect is at its best According to Panasonic the SY DS1 is designed to expand this area to al low more people to experience the ef fect of surround sound 250 CIRCLE NO 124 ON FREE INFORMATION CARD Design Stations Wishmaker 1 and Wishmaker 2 from Jameco Electronics are prototype de sign stations designed to meet the needs of electronics engineers tech nicians and students The two models unm iau T EAS same T ot be aviv ad are said to simplify the building and testing of prototype analog Wish maker 1 and digital Wishmaker 2 circuitry Each includes a removable solderless breadboarding system va riable or fixed dc power supply mul tiple frequency signal generator an alog multimeter fused overload pro tection logic probe and more 199 95 Wishmaker 1 249 95 Wishmaker 2 CIRCLE NO 125 ON FREE INFORMATION CARD A D Converter Alpha Products Darien CT an nounced a high speed 12 bit analog to digital converte
151. nect to an IBM PC or an Apple Macintosh for 99 95 a 32K RAM card for 79 95 a 128K RAM card for 250 an HP Solve Equation Li brary Application card for 99 95 and a portable infrared printer the HP 82240B for 135 Operating the HP 48S X The first things you notice about the HP 48SX are its 2 5 by 1 4 inch LCD and the keys and key legends on its face What you reless likely to no tice are the serial port and infrared LEDs on its back panel When turned on the LCD shows a status line four storage areas the first four levels of thestack for RPN calculations and a menu bar With a press of two keys the screen blanks and becomes an electronic chalkboard where you can enter formulas almost exactly as they appear in a textbook see Fig 1 Nothing special is required to enter equations in this way just press the appropriate keys Of the 49 keys 12 perform at least four functions and 22 perform at least three Like most calculators the main function of the key is printed on its face and its other functions are printed in different colors around it However some things such as low er case characters are not even in cluded on the keyboard most likely due to the lack of space To get a key to perform a function other than the one described on its face you first check the color of the function you want and press a special blue orange or alpha key before pressing the key itself You can select functions from
152. ngly slow and re quires the use of two programmers In contrast the Programmer to be described is the only one needed to program the 68701 chip It is flexible fast and easy to use as well Operated from a single 5 volt dc supply it fea tures its own dc to dc converter that provides the 21 volts required for successful programming Light emit ting diodes indicate the status of the programming process and a parallel printer port permits connection to virtually any personal computer About the Circuit Figure 1 is a block diagram of the va rious elements that make up the Pro grammer As youcan see at the heart of the six basic blocks is the one la ns D beled CPU The heavy lines routed from the CPU to the LED INDICATORS and PRINTER PORT blocks indicate an eight line bus All other lines indicate single conductor lines between the various elements that make up the Programmer Figure 2 is the schematic diagram of the Processor and Memory cir cuits Microcomputer chip U8 runs the programming process When power is applied to the Programmer 24 MODERN ELECTRONICS May 1990 iy n r v VERIFY v ima PROGRAM LOAD L P L E T F a a Lif L 1 L Lj U8 begins in mode zero the only mode that allows the EPROM to be programmed Instead of fetching the reset vector at FFFE U8 fetches the starting address f
153. nnected to circuit ground touch the hot probe to pin of U2 and adjust the setting of trimmer control R70 for a reading of 21 volts If you are using a digital meter you may notice that the reading jumps between 20 8 and 21 2 volts This is caused by the slow switching speed of U2 When the 68701 that will be plugged into the U8 socket is not programming its EPROM there is very little current drawn so the slow switching speed will effortlessly keep up with the demand Now use the hot probe to mea sure the potential at RESET pin 6 of the U8 socket Your reading should be about 4 9 volts If it is 21 volts Or SO there is a problem with the circuitry around Q7 and D3 if near ground potential the problem is in the Q2 circuitry Whatever the case if a problem exists power down the project and rectify the problem Once you obtain the proper read ings at all specified points in the cir cuit power down the Programmer May 1990 MODERN ELECTRONICS 31 A a eS S A 68701 Assembly Language Programming Example remove the meter from the circuit board assembly and allow the charges to bleed off the electrolytic capacitors Then plug the ICs into their respective sockets Install an erased 68701 in the U8 ZIF socket Note Whenever you install or re move the 68701 make absolutely cer tain that you first disable power to the circuit Otherwise you run the risk of permanently damaging the microcompu
154. nt magnification TV sync coupling a camera mount CRT bezel variable scale illumination and single sweep operation for photographing dis played waveforms and Z axis input for blanking or intensified markers 1 290 CIRCLE NO 132 ON FREE INFORMATION CARD Multiple DC Outlet MFJ Enterprises Mississippi State MS Model MFJ 1112 Multiple DC Power Outlet is designed to save space on a crowded testbench by pro e T a SE EEE viding six pairs of heavy duty color coded binding posts for connection to circuits The device connects di rectly to any 12 volt dc power supply and includes bypassing to keep r f out of thesupply from the dc line out let It measures just 135 x 2 x 2 inches 24 95 CIRCLE NO 133 ON FREE INFORMATION CARD 82 MODERN ELECTRONICS May 1990 Dni nd Slide Projector rom page 43 SS eee SSS ee the control unit might trigger on the projector and change a Slide If this occurs back off on the setting of the trimmer potentiometer just a bit The only loss in doing this will be that the projector will not switch on at the very bottom of the travel of the slide control You may be concerned that the projector will not have time to cool down if it is switched on and off in normal operation This is not the case however Intests with a number of different slide projectors no ex cessive temperature was reached If the projector is on for a long period of time th
155. nt lamps are derived from this fundamental discovery In 1841 Frederick de Moleyns received an English patent for an incandescent lamp that consisted of a two closely spaced platinum electrodes installed in an evacuated glass sphere Powdered car bon between the electrodes became in candescent when an electrical current flowed through the two electrodes In 1850 Sir Joseph W Swan another Englishman devised incandescent fila ments from paper and cotton thread He treated the thread with sulfuric acid to re move everything but the carbon The car bonized thread was installed inside an evacuated glass envelope to produce what Swan called an electric glow lamp In the United States Thomas Edison announced in 1878 that he intended to invent a practical electric light suitable for use in homes Based on his reputation as a highly successful inventor a syndi cate of investors advanced Edison 50 000 for the electric light project The inves tors even formed the Edison Electric mm M n n X Un Mps m FLASHING LED Qt 11111 NS RELAY CSEE TEX T Fig 1 A simple relay lamp flasher Light Company before the inventor had made his first lamp Edison at first attempted to find a fila ment material that could be heated to a higher temperature than the carbon used by his predecessors thereby pr
156. o place Install the three LEDs in their re spective locations on the edge of the circuit board assembly as shown Note that if any LED overhangs the edge of the board it should do so by no more than inch as illustrated in Fig 11 Usea short length of No 32 bare wire for fuse F7 Machine the enclosure that will house the receiver module This is done in basically the same manner that was described last month for the transmitter module except that an extra hole to provide access to trim mer GAIN ADJUST potentiometer R7 is required in the rear panel If you are using the type of enclosure sup plied with the kit see Parts List use the actual size machining templates provided in Fig 12 as guides for the rear A and front B panels If you are using any other type of enclosure make suitable adjustments in the templates before using them for ma chining the panels When machining of the panels is complete do not set the self stick front panel overlay in place You must first mount the front panel in place on the enclosure using the small screws provided before at tempting to mount the overlay which then covers the entire panel including the screw heads There fore save installation of the front panel overlays on both the transmit ter and receiver modules until after the entire system has been checked out for proper Operation Meanwhile pass the unfinished end of the ac line cord through its hole in
157. on Harbor Michigan 49022 res Comoran A subsidiary of Zenith Electronics Corporation CIRCLE NO 151 ON FREE INFORMATION CARD May 1990 MODERN ELECTRONICS 51 Technology Interfacing 555 Timers A hands on look at real world use of this ubiquitous and very versatile IC timer chip By Joseph J Carr he 555 timer chip ranks as per l haps the all time most popu lar device in the IC arena with good reason Its immense popu larity derives from the fact that the 555 is inexpensive well behaved and is so utterly useful in an almost limit less variety of applications Since a lot has been written over the years about the 555 we will not begin at the beginning here We will assume that you either already know the basics or where to look for them Instead we will concentrate in this article on in terfacing between the 555 device and the outside world Definitions Shown in Fig are the package and pinout details for the popular eight pin mini DIP version of the 555 timer In reviewing pin function defi nitions and their uses keep in mind that high means a potential that is greater than 2 V 3 and low means either a grounded condition where V O as in the case of the RESET pin or a potential that is less than V 3 as in the case of the TRIGGER pin Pin function definitions for the 555 timer are as follows e GROUND pin 1 serves as the com mon ref
158. on of U S mo torcycle makers was going down the drain A group got together and bought the company changed its production methods and created a revitalized cycle maker that makes a profit and has moved into the forefront of the motorcycle in dustry all in a very few years The cata lyst was the U S Government by the way which helped out for a few years with a declining import tax on foreign made cycles over a certain size What has all this got to do with elec tronics Well it sort of parallels what happened in this industry For example from an 18 price to volume buyers in 1984 256 Kbit DRAMs plummeted to only 1 80 in 1987 with immediate de livery U S makers of dynamic random access memories blithely dropped mak ing these chips accusing Japanese sup pliers of dumping One year later with Texas Instruments and Micron Technol ogy the only remaining major U S DRAM makers thechips were being sold for 4 50 with delivery ranging up to 20 weeks To ensure a U S supply of DRAMs a consortium U S Memories Inc was formed in 1989 by seven computer and semiconductor makers They anticipated support by other U S companies of course expecting some 25 or 30 more to kick in some money and commit to buy ing at least 20 percent of their DRAM needs from the consortium But as the whole thing was revving up the shortage of Japanese DRAMs began to subside by late 1989 From among some 60 U S computer companie
159. on was answered on March Ist with the introduction of the LaserJet III I ve had one for several weeks now and have to admit I m impressed H P has really done its homework with this printer and set some new standards both in features and price performance H P LaserJet III Hewlett Packard has gone through four releases of their 8 ppm laser printer The original LaserJet gave way tothe LJ Plus Series II and the Series IID the latter a duplex printer able to print on both sides of a piece of paper H P s IIP the 4 ppm personal laser reviewed here last month redefined the low end of the laser printer market While the IIP defines the low end of the laser market the new LaserJet III will most likely do the same for the 8 ppm market in laser printers The latest model is based on the same Canon SX laser engine used in the Series Laser Wars CALE am x s Mis var Hewlett Packard s new LaserJet II laser printer II which it replaces Though it uses the same laser engine it is nonetheless a ma jor upgrade to H P s laser printer line While the internal mechanicals remain the same almost everything thing else about the printer has been improved The most noticeable difference on a first look is the case Although the print er has the same basic footprint as the Se ries II it has had a complete styling rede sign and looks much sleeker The control panelisstill located on the front right side of
160. op which they sit the scope you use has a three prong power cord plug use a three to two prong adapter between it and the ac outlet before use System Installation Placement of the Extended Play transmitter s and receiver in your home depends as much on room lay out ason personal taste You can pre test different locations for the receiv er using a hand held remote control transmitter to emulate the proposed positioning If a given location works well with the remote control trans mitter it will almost certainly work as well with the receiver As a matter of convenience you may want to experiment with placing the receiver directly on top of or alongside your VCR If a window or light colored wall directly faces the VCR from across the room the re ceiver should be able to beam the control signals at the wall with enough energy that they reflect back to the VCR without significant loss The transmitter can be placed be side or atop most TV receivers with out experiencing erratic behavior However computer monitors pro duce a great deal more emi electro 50 MODERN ELECTRONICS May 1990 magnetic radiation or noise than do TV receivers If your remote TV re ceiver is located close to a computer try to keep the Extended Play trans mitter at least 24 inches from the computer monitor Any interference from the computer monitor can be identified by continuous erratic flashing of the transmitter LED So
161. or drum and less toner being placed on the paper during printing Being the leader has both advantages and disadvantages If you are successful you get to set the standards At the same time the competition gets to ride on your coattails by offering the same features for less money or more features for the same money This has proved true in the vola tile laser printer market With the Laser Jet III H P has set a new level of feature performance At the same time it has al so set a new level of price performance The Series II with 512K of RAM was priced at 2 695 The LaserJet III has IMB of RAM built in and can be ex panded to 5MB It also has PCL 5 scal able on the fly fonts and font rotation and the Enhanced Resolution feature It gives you all of this for 2 395 And H P has sweetened the pot even more by dropping the prices on its disk based scal able typeface products from 195 to 99 I thought the IIP was a good deal at 1 495 I still do But the LaserJet III at 900 more gives you a lot for that extra 900 If the IIP is a good deal the Laser Jet III is a great one It s going to make choosing between them a hard choice Horizontal smoothing is accomplished by using smaller dots and by offsetting dot placement by varying on off timing of the laser beam This allows dots of in creasing or decreasing size to be placed close together creating a gradually rising ramp rather than an abrupt stai
162. or merchandise NOT AT K D VIDEO We are a well established company that will offer you the best quality service and prices WE SPECIALIZE IN DEALER PRICING Cal TOLL FREE 1 800 327 3407 K D VIDEO INC P O BOX 29538 MLPS MN 55429 ELECTRONICS MINIATURE FM TRANSMITTERS Tracking Transmitters Voice Disguisers Bug Detectors Phone Devices More Available in kits or assembled and tested Catalog 2 00 XANDI ELECTRONICS Box 25647 YY Tempe AZ 85285 5647 SURVEILLANCE Countersurveillance Equipment Catalog 5 00 Eavesdropping De tection Equipment P O Box 1087 Williams ville NY 14231 e uu Et TAPELESS V L S l C Handsize Thirty Second Message Digital Voice Recorder with built in mike Playback thru built in speaker activated by motion detector 4 5M range Powered by nine volt battery and or AC adapter both supplied Memory retained on battery Model ME10 ME 20 Send 99 99 5 00 S amp H to MAC 335 High St Metuchen NJ 08840 M C VISA COD 1 800 888 9428 NJ Res add 6 tax T E N S ELECRONIC PAIN KILLER Electrical nerve stimulator blocks out pain Declared effective by the F D A Construc tion plans 14 95 Send M O to KREM EN GINEERING 279 20465 Douglas Crescent Langley B C Canada V3A 4B6 FUZZ BUSTER BUSTER lt Activates RA DAR DETECTORS Great for testing Radar Detectors at Hamventions Build from parts in your shack For complete plans assembly instructions and parts
163. or off Projector switches on Output IC3 Pin 6 ee No change B Fig 5 Timing diagrams for A fading out lamp changing slide and switching off projector and B switching on projector and fading up lamp Waveforms are not to scale May 1990 MODERN ELECTRONICS 41 Fig 6 Actual size etching guides for A main and B junction box circuits and shrink it into place Next wire the LEDs into the cir cuit making certain that you make the correct connections to the anode and cathode leads Insulate all con nections with heat shrinkable or oth er plastic tubing Then wire the switches and slide or rotary control into the circuit Plug the LEDs into their respective holes in the top panel of the enclo sure If the LEDs do not remain in place by friction secure each with a small daub of silicone adhesive or fast setting epoxy cement Machining of the smaller junction box in which the smaller circuit board assembly is to mount requires drilling of only three holes One hole is needed for mounting the circuit board assembly insidethe smaller en closure Then one hole is required for entry of the control cable from the main unit and another for exit of the cable that goes to the projector Af ter all holes are drilled deburr them to remove sharp edges and line the cable holes with rubber grommets Prepare the unfinished end of the control cable as detailed above Pass the cable through its hole i
164. oviding a brighter and more practical light source Oxides of thorium and zirconium seemed good candidates but they could not be formed into filaments Finally Edison resorted to the carbonized thread fila ment and on October 21 1879 he dem onstrated a lamp that operated continu ously for 40 hours Two months later he demonstrated a pilot light and power sta tion at his Menlo Park NJ laboratory The system powered 30 lamps any one of which could be disconnected without af fecting the status of the others Incidentally it s interesting to note that from the outset Edison proposedto connect electric lamps in parallel circuits so that the failure of one lamp would not affect the remainder Some scientists pre dicted the parallel method would not be practical Sir William H Preece for ex ample said as much in a paper heread be fore the Royal Society in London For tunately Edison had only three months of formal education in his youth so he could safely ignore the pronouncements of formally trained scientists Of course the parallel electric light circuit proved practical and it greatly enhanced Edi son s fame as a gifted inventor As for the skeptical Sir William s scientific leg 58 MODERNELECTRONICS May 1990 acy I had never heard of him prior to preparing this column Blackbody Radiation Everything above the temperature of ab solute zero which is presumably every thing emits electromagnetic r
165. p CRT Readout DVM Counter 1mV sens Delayed Sweep Cursor Meas DVM Counter 495 a luminance 6 CRT 1mv Sensitivity 6KV Acceleration Voltage 10ns Rise Time X Y Operation Z Axis Delayed Triggering Sweep with purchase of ANY SCOPE Top quallly scopes at a very reasonable price Contains all desired features Two 1x tOx probes diagrams and manual Two year guarantee PRICE BREAKTHRU on Auto Ranging DMMs f EE 310 M 7000 m 37 E from 05 DC Accuracy MDM 1180 1 Resistance 24 95 with Freq Counter True RMS 4 Digit Multimeler and deluxe case 27 95 Bench DMMS D REI 29 95 M 3500 M 4500 3 1 2 LCD Dispiay 27 Functions 3V digh 125 ov digit 175 05 accy Auto Manual Pumnges Audible Continurty Data Hold MDM 1182 1 6 Accuracy NMOM 1181 f 1 accy Soldering Station Temperature Controlled SL 30 99 Dagta delay T f so0F 900 Grounded tip Overheat protect Finest in the industry tO rock steady patterns 69 95 Wide Band Signal Generators G 9000 129 RF Freq 100K 450MHz AM Modulation of 1KHz Variable RF output G 8500 with Digitel Display end 8 50MHz bullt in Freq Cir 249 Digital Triple un el XP 765 249 0 20V at tA 0 20V at tA 5V at 5A Fully Regulated Shoe circuit protected with 2 Limit Coni 3 Separate supplies XP 660 with Analsg Meters 175 F 100 120MH 179 F 1000 1 2GH Frequency Period Totalize 25
166. pin SIP resistor network with pin common Miscellaneous J1 Two position power terminal strip Mount power terminal strip J7 DB 9S serial connector J2 and paral lel printer connector J3 in their re spective locations Then mount and solder into place trimmer potentio meter R O Finally mount suffici ently long legs at the four corners of the circuit board assembly for the components mounted on it to clear whatever surface upon which the project sits Use suitable length spac ers and machine screws for the legs Alternatively you can build a wood en frame of sufficient depth in which to mount the Programmer to accom plish the same ends Initial Checkout The only instrument you need to check out the Programmer is a dc voltmeter or a multimeter set to the dc volts function Clip the common lead of the meter to a suitable circuit ground point such as pin 2 of JJ With no ICs installed in the sockets apply 5 volts dc tothe Programmer J2 Pc mount DB 9S serial D type connector J3 Pc mount 36 pin parallel printer connector JP1 Single jumper assembly JP2 6 x 2 jumper assembly Y1 2 4576 MHz solder mount crystal in HC 18 case Printed circuit board or perforated board with holes on 0 1 inch centers and suitable Wire Wrap hardware see text sockets for all ICs except ZIF socket for U8 see text 5 volt 500 mA dc power supply see text solder etc Note A minimal EP701 Programmer kit co
167. point to point wiring on perfor 40 MODERN ELECTRONICS May 1990 fe ated board use the wiring guides shown in Fig 7 as rough layouts for the components When wiring the board install and solder into place first the sockets for the ICs and optical isolators Do not plug the ICs into their respective sockets until you have conducted preliminary voltage checks and are certain that everything is okay If you cannot locate six pin sockets for the optical isolators carefully cut down sockets with more pins or substitute Molex Soldercon socket Strips With the sockets in place install and solder into place the resistors and trimmer controls then the diodes and capacitors Note that most resis tors and diodes mount vertically on the board Make certain that you properly orient any electrolytic capa citors and all diodes before soldering their leads into place Next install and solder into place regulator C and then the power MOSFETs followed by the triacs Again make absolutely certain that each of these devices is properly based before soldering any leads into place Note that anumber of components associated with the large main cir cuit board assembly mount off the board These include the power transformer all three switches the three LEDs and slide potentiometer R15 To make connections to these components you must install suit able length wires at the indicated lo cations Make these wires about 4 in che
168. pulses disappear and the output at pin 1 of C2B is always high Conversely when the voltage set by R75 has an amplitude that is less than that of the sawtooth the pulses again disappear but this time leave the output continuously low Whenthe output at pin 1 of C2B is zero both LEDI which is in the cir cuit to give an indication of the lamp brightness in the projector and the LED inside optical isolator C6 see Fig 2 will always be lit With the LED inside C6 on the internal triac is triggered into conduction and in turn drives external triac Q5 into full conduction As R15 is adjusted toward its alter nate stop position pulses synchron ized with the 60 Hz ac line will be generated Both LED and the LED internal to C6 are briefly switched off during each half cycle as are the internal and external triacs As a re sult the projector lamp will not be receive full 117 volt ac line voltage all the time The lamp will be dimmed progressively as R75 is adjusted to ward its far end of travel Capacitor C4 filters out any noise that might be picked up by the leads from R75 from entering C2B via input pin 3 This capacitor should be placed as close as possible to the pin 3 input during assembly of the circuit All of the above assumes that the 117 volt ac line power to the projec tor is on but at the beginning of the process the projector is off and wait ing for the command to show the first slide in the c
169. put status The main program begins by loading Accumulator with the data from Port 1 and storing it at the Port 3 data regi ster Since Port 3 is all outputs data written to its Data Register immediately appears on the Port 3 pins of the 68701 Next Accumulator A is complemented and stored at the Port 4 Data Register Finally the program jumps back to LOOP the top of an infinite loop The interrupt vectors are the last part of the listing There are eight vectors and each one is a 16 bit address The processor requires the vectors to be at the very top of the internal EPROM for all modes of operation except mode zero An FDB Form Double Byte di rective places a 16 bit value at the next two bytes in memory For the example in Listing 1 all vectors are set to the la Listing 3 Assembler S19 Output File bel RESET which is address F800 When poweris applied to the 68701 a reset interrupt is generated and the vec tor at FFFE is fetched In this case ad dress F800 will be fetched and the pro gram will begin to execute there The in itialization code will run followed by the main loop The processor will con tinuously read the data on Port 1 out put it on Port 3 and output its comple ment on Port 4 When the source code is assembled using the freeware cross assembler from Motorola two files are created These are the Listing File given in List ing 2 and the S19 Output File given in Listing 3 The Listin
170. r board that ex pands its line of A BUS devices for low cost data acquisition and con 10 MODERN ELECTRONICS May 1990 trol devices The Model FA 154 board s conversion speed is rated at 10 microseconds and each of its eight input channels accept a 0 to 5 volt signal An on board variable gain amplifier permits reading of sig nals that are less than 1 2 mV 1 LSB The board runs on most popu lar computers including IBM PC bus machines Apple Ils Commo dores etc Furthermore serial inter faces permit operation through any comp iter s RS 232 port 179 CIRCLE NO 126 ON FREE INFORMATION CARD Frequency Adapter A new adapter designed to provide direct frequency readout on any mul timeter is available from EXTECH Instruments Corp Waltham MA The converter provides frequency measurements over a range from 2 kHz to 20 MHz with a rated accuracy of 1 of reading Minimum sensitiv Say You Saw It In Modern Electronics How to build a high paying career career o even a business of your own in computer programming baud internal modem 640K RAM disk drive monitor and invaluable programming software BASIC Pas cal C and COBOL all yours to keep You get the experience and the know how the computer and the software to get to the heart of every programming problem design imagi native solutions then use your choice of four key computer languages to build original working programs
171. r step The enhancement can be set to light me dium or dark or turned completely off from the control panel Resolution Enhancement is not some thing that jumps out at you If you aren t looking for the effect you might not no tice any difference The overall visual ef fect though is that the pages just look slightly crisper as if they were printed at a higher resolution If you already have a Series II LaserJet and really want the en hanced resolution you won t have to sell or discard your old printer to get it H P will offer an upgrade later in the year that will give Series II owners PCL 5 and Res olution Enhancement Also third party add in boards such as Intel s Visual Edge and others available from Laser Masterand DP Tek also allow a Series II printer to produce up to 1 000 dpi hori zontal resolution the new printer is any faster than the Se ries II It doesn t seem to be but then the Series II has always delivered perfor mance very close to the 8 pages per min ute Hewlett Packaged claimed for it ME In most other respects the LaserJet III is very much like the Series II It uses the same EP S cartridge containing the pho toconductor drum developer and toner and sets up in about 2 minutes The new PCL 5 is downward compatible with ear lier versions It worked perfectly with all of the applications I had configured for a Series II printer Without performing a formal printer benchmark I c
172. reen dis plays its logo and the directive Press F1 for help Unfortunately it s not immediately evident from the help screen how to access the program s main menu or how to issue com mands If you use the documenta tion you have to leaf through a few pages before it tells you to press F10 to access the main menu Learning to use the program is rarely an intuitive trial and error experience it is most ly a look it up in the documenta tion one Everything you doin MathCAD enter formulas place text or sketches or produce graphs you do free form on a display that emulates a scratchpad To move around the scratchpad you use the cursor keys or issue a go to command with the coordinates of the desired position This is a cumbersome way to do things and is one of the least appeal ing features of the program Once you reach a desired position you en ter a formula for example by typing numbers letters mathematical oper ators or math symbols The program requires that you define variables be fore you use them in a formula This is done by typing the variable name followed by a colon and a number Math symbols are created with keyboard symbols or with Alt key combinations For example an inte gral sign is created by typing an am persand amp and a less than or equal to symbol is created by typ ing Alt To distinguish explanatory text from text used to represent vari abl
173. rojector but can be tethered to main control unit via a cable up to 100 yards long the ICs and optical isolators into their respective sockets Make sure each is in its proper socket and is properly oriented and that no pins overhang the sockets or fold under between devices and sockets Set R76 and R17 to about mid po sition Plug the projector into an ac outlet plug the cable coming from the small branching box into the pro jector and plug the control cable into the main unit Plug the main unit into an ac outlet The projector fan may start operating and the lamp light though not at full brightness in the projector at this point Operate the slide control up and down to see 1f this action dims and brightens the projector lamp lf it al lows the lamp to go out completely the projector mechanism should ad vance to the next slide and switch off Adjust the setting of R76 until the slide advance process is completed before the projector switches off Leave the slide control in a position that leaves the projector lamp just glowing dimly l Adjust the setting of R74 to bright en the projector lamp and move the slide control until the lamp just glows again Repeat the process as many times as necessary until the slide con trol is at the out end of its travel Now adjust the setting of R74 to completely fade out the lamp at which time the slide should change and then the projector switch off If R14 is set
174. rol theory You can load and run applications in the pack just as you would any other MathCAD documents The applications implement common solution methods and the documentation provides a brief background for the application To give you an idea of what one of the applications looks like we ve included part of the Design of an IIR Filter application here The application de signs a low pass digital IIR filter of the Butterworth type The user specifies the minimum stopband attenuations and defines the width and location of the transition band by specifying the pass band and stopband edge frequencies MathCAD calculates the required fil ter order and constructs the transfer function The routine provides coeffi cients for the transfer function and for its expansion in partial fractions from which the impulse response can be cal culated The application also finds the filter output for some simple input se quences in two ways by direct convolu tion with the truncated impulse response and by using a difference equation based on the transfer function coefficients a mA IMSXALGTUON E s S Aw eeu a ccc Om z j um MathCAD EE Applications The coefficients of the numerator are To find the impulse response h for this filter first find coefficients for the partial fraction expansion of the transfer function H r 001 P n2 n l K Ale exp 3 8 a k 2 0 k Ctrl PgDn H expanded in
175. rom BFFE in mode zero Table 1 shows the memory map of the Programmer The operating pro gram and interrupt vectors are pro grammed into 2764 EPROM U6 This program determines the 68701 type in use standard or U4 version Say You Saw It In Modern Electronics Table 1 Memory Map for Programmer 68701 68701U4 0000 00 I F 0020 007F 0020 003F 0080 00FF 0040 00FF 0100 5FFF 6000 7FFF i 8000 9FFF A000 BFEF BFFO BFFF s C000 DFFF 3 E000 F7FF E000 SEFFF F800 F FFF F000 FFFF and adjusts the size of the buffers in 6264 RAM US accordingly The status of the programming process is indicated by light emitting diodes LED through LED7 in Fig 3 A Each pair of LEDs is assigned a different function to monitor and re port upon whether the process was a sek BL eck E P1S P 16 Rt PL P22 P23 P245 ECK RSTN MPU Registers 68701 Unused Internal RAM 68701 Unused Printer Port Input External RAM 6264 External EPROM 2764 External Interrupt Vectors 2764 LED Output Unused Internal EPROM 68701 success OKAY or a failure FAIL with green indicating success and red indi cating failure For LED and LEDS the function is ERASED LED2 and LED6 LOAD LED3 PROGRAM and LED4 and LED7 VERIFY In this Programmer the Serial Port shown schematically in Fig DCO 73 CK b e ese Fig 1 Ov
176. rom your remote control trans mitter Although not recommended for more than a few seconds at a time this test will easily show that everything is working as it should When you are confident that both units are performing satisfactorily it is time for atest using the actual com ponents tlie system will control AI though the following procedure can be accomplished with a CD player stereo system or any other IR con trolled appliance a VCR and some means of sending its output to a re motely located TV receiver will be as sumed Of course if you have any of these other devices you can use one of them instead Mount the front panels on the transmitter and receiver unit enclo sures with the provided screws and carefully iastall the overlays so that Fig 12 Machining templa io PCB 16 INCH MAX RIGHT SIDE VIEW Fig 11 Mounting details for the LEDs on the receiver pc board the translucent red filter sections are positioned over the rectangular cut outs in the panels Slide the circuit board assemblies into their enclo sures and mount the rear panels in place again with the supplied screws Position the Extended Play receiv ENTRY er module across the room from your VCR so that its front panel IR win dow faces the front of the VCR ata distance of not more than 18 feet Plug the receiver s line cord into a convenient ac outlet Use a small screwdriver to slowly adjust the GAI
177. s Programmability 2D plots 3D plots Displays math symbols Displays explanatory text Prints a document Electrical engineering modules Price you ll notice that Derive receives a 5 due to its excellent implementation of this feature The HP 48SX receives a 3 because the feature is useful but has some drawbacks as noted inthe review The other programs receive a 0 because they lack this feature Again if this is a feature you want to see in your pro label name beside it as shown in Fig 4 You can store up to nine num bers in this area and an additional 41 more that are not displayed If you want to automate proce dures you can do it by entering MEM at the prompt CMPCALCA lets you enter upto 500 steps and save them to a disk file To re run the sequence of steps you load the file from disk with the LOAD command and then enter the RPT command CMPCALC4 Features The obvious highlight of this pro gram is its ability to perform mathe matical operations on complex num bers Besides the four main opera tions and the program 22 MODERN ELECTRONICS May 1990 MathCAD 5 0 0 4 5 5 5 2 5 4 5 gt 5 5 495 Derive CMPCALC4 HP 48SX 0 5 5 2 4 4 5 0 5 4 4 4 Z 0 oocococoowmoouwoooo VENN 4 amp QD tA tA tA tA tA 4 OW OS on O on 200 gram the Table can help you in your decision The Table can also assist you in choosing products other than the ones reviewe
178. s not a single one 6 MODERN ELECTRONICS May 1990 joined the consortium No Apple Com puter Compaq or Sun Computer among others who declined to join the founders which included Digital Equipment Corp and IBM With the DRAM shortage gone so was any interest The U S Gov ernment looked the other way too as did other sources of financing Finally U S Memories called it quits as it entered the Nineties still born It s really shameful I think Such shortsightedness will seriously hamstring future DRAM production l Mbit and 4 Mbit onward to 16 Mbit and 64 Mbit It seems that we have lost the will or the wherewithal to engage in large scale semiconductor production battles and will settle largely for niche production Japan and Korea now own about 79 per cent of the world s DRAM market It sa market that will grow enormously in size due to expanding applications from high definition TV to computer worksta tions Moreover the technology of mak ing DRAMSs is akin to that of producing LCD screens a product area that s ex pected to burgeon It too requires lots of money to be invested in production equipment Will the U S walk away from this opportunity too Probably All isn t lost in the memory world say some industry sages We ve got the lead in flash memories which some think might become a more important memory device Specialty static and dynamic RAMs too are significant memory mar kets that ar
179. s French presented complete construc tion details for a battery powered fila ment lamp transmitter and receiver in the April 1944 issue of QST pp 22 25 and 86 88 French s system operated in ei ther blinker or voice mode The former yielded a range of up to 12 miles the lat ter up to 0 5 mile Incidentally French didn t feel that a filament lamp could react rapidly enough to a fluctuating signal to produce a mod ulated light beam Heattributed the mod ulation to physical vibration of the lamp filament An ordinary flashlight point ed at the photo tube and tapped with a pencil or other solid object will give a bell like tone at the receiving end prov ing that mechanical vibration will pro duce sound French s conclusion was wrong but he was decades ahead of mein discovering that a vibrating lamp fila ment produces a modulated light beam In the Experimenter s Section of the October 1944 issue of QST p 38 Roger Houglum observed that In prac tically all the light beam transmitters de scribed in QST the audio frequency cur rent from a low impedance winding on an output transformer is used to vary the intensity of the light from a flashlight bulb Tests with several of these transmitters revealed that the audio qual ity at the receiver end was passable on voice but downright poor when music was used Houglum then demonstrated how a small battery and low resistance rheostat in series with
180. s are available as 1K IDT7252 and IDT72520 or 0 5K IDT7251 and IDT72510 devices The x18 to x18 bi FIFOs are also available as 1K IDT72521 or 0 5K IDT72511 devices An IDT biFIFO gives designers a sin gle chip buffering solution that replaces up to 17 devices This translates into higher integration reduced board space and lower power consumption Another benefit is that the x18 to x9 width allows designers to match the bus from RISC microprocessors to any standard 8 bit or 16 bit peripheral A pass through feature of the biFIFO provides a direct data path through the biFIFO while bypassing buffers to speed communication and eliminate ex tra external logic Eight flags are available on the bi FIFOs Empty full almost empty and almost full are generated internally for both FIFO memories Programmable flag offsets for almost empty and al most full can be set at any depth Pro grammers can assign any four of the eight flags to four external flag pins The family of biFIFOs features a pro cessor interface that determines the per sonality of the biFIFO by programming the flags and the DMA handshake struc ture On the IDT72521 and the IDT72511 the processor interface pro grams the I O logic as well The IDT7251 and IDT7252 in 48 pin plastic DIP packages sell for 77 49 and 86 10 respectively in 100 and up quanti ties The IDT72520 sells for 90 41 and the IDT72510 for 81 36 in a 52 pin PLCC package The I
181. s long Strip inch of insulation from both ends of each If you are us ing stranded hookup wire tightly twist together the fine wires at both ends of all wires and sparingly tin with solder Then plug one end of each wire into the indicated hole and solder into place Keep in mind that two copper con ductors on the smaller junction box pc board both associated with triac Q5 carry about 3 amperes of 117 volt ac line power These are indicat ed by extra heavy traces in the small er guide in Fig 6 Strengthen these Say You Saw It In Modern Electronics traces by soldering along their lengths thick pieces of heavy duty bare copper wire before installing and soldering triac Q5 into place You can use any enclosure you wish to house the large circuit board assembly It must be large enough to accommodate the assembly and pow er transformer and have enough panel space on which to mount the switches control and LEDs Ma chine the enclosure as needed see lead photo for a suggested panel lay out including drilling the hole for entry of the five conductor control cable I you do not have the proper tool to makethelong narrow slot for the slide control substitute a rotary control Of course doing this sacri fices some of the feel for smooth fades in and out After machining the enclosure de burr any holes drilled through metal to remove sharp edges Line the ac line cord and control cable entry hole
182. s with rubber grommets and mount the switches slide or rotary control and five pin connector in their respective locations Mount the power transformer with suitable hardware Solder the transformer s secondary leads in the appropriate holes in the circuit board assembly Trim 1 inches of outer plastic jacket from the five conductor cable and strip inch of insulation from all conductors Tightly twist together the exposed wires of each conductor and sparingly tin with solder Pass this end of the cable through its rubber grommet lined entry hole and secure a large plastic cable tie tightly around it about 4 inches from the end inside the enclosure to serve asastrainrelief Plug the conductors into the holes labeled 5v FROM LEDI SLIDE FORWARD COMMON and SLIDE REVERSE Make a note on a slip of paper of the color coding used for each conductor connection then mount the circuit board assem bly with inch spacers and 4 40 x 34 inch machine screws lock washers and nuts Say You Saw It In Modern Electronics Note Instead of making direct ca ble connections to the circuit board assembly you can mount a female DIN type five pin connector in a suitable hole in the enclosure and wire from it to the circuit board as sembly Then terminate one end of the control cable in a matching five pin male DIN type connector as il lustrated in the cover photo Tightly twist together the wires in each conductor of the ac line
183. sher you can assemble from a flasher LED and a single transistor This flasher LED switches the transistor on each time it flashes thereby pulling in the relay arm and switching on the lamp used an FRL 4403 flasher LED in the prototype of the Fig 1 circuit This LED flashes around three times per second Other flasher LEDs should also work The relay should have a 6 to 9 volt 500 ohm coil such as Radio Shack s Cat No 275 004 relay does Unfortunately this relay is no longer stocked by Radio Shack so you will have to search your spare parts box or borrow one from a friendif you want to experiment with this p Vr RS look et R4 RZ tyF LK EDO oa E ON n gt Lap B R3 BS LK SPKR A KEEP POWER SUPPLY LEADS SHORT Fig 4 A simple lightwave receiver circuit particular relay Other low voltage 5 volt relays with a high coil resistance may also work in the Fig circuit The flasher LED in Fig 1 does not emit visible flashes when used as shown Fig ure 2 a modified version of the circuit permits the flasher LED to flash in step with the incandescent lamp This verifies that the circuit is functioning properly in the event the incandescent lamp burns out In operation R2 must be adjusted until the lamp begins to flash It may some times be necessary to readjust the setting of R2 if the circuit stops flashing While the flasher LED does emit a visible flash it isn t as bright as when the flasher L
184. single sup ply operation rail to rail output swing and extremely low input bias current The LPC660 quad and the LPC662 dual opamps are micropower versions of National s popular LMC660 662 CMOS op amps Since they require very little supply current and can operate from a single ended power supply 5 to 15 V the new op amps are ideally suited for many low power applications Examples include battery powered hand held me ers and medical instrumentation Types of circuits that take advantage of the features of these op amps include low leakage sample and hold circuits and low frequency filters In a filter cir cuit the low input bias current of the LPC660 662 allows the designer to use larger resistor values and therefore smaller capacitors saving board space without degrading performance In a sample and hold or peak detector cir cuit the same low bias currents improve signal accuracy by decreasing the leakage current from the holding capacitor 1 The devices are fabricated with Na tional s acvanced double poly silicon gate CMOS process and have an operat ing range of 4 75to 15 5 V The LPC660 and LPC662 are available in 14 and 8 pin plastic DIPs respective ly in industrial temperature range units priced at 1 40 in quantities of 100 for the LPC660IN and at 0 90 for the LPC662IN Digital Devices 80C52 BASIC Processor The 80C52 BASIC processor from Micromint 4 Park St Vernon CT 06066 is a C
185. t 5 tolerance R1 15 000 ohms R2 R3 10 000 ohms R4 R5 100 000 ohms R6 100 ohms R7 R10 R12 56 ohms R8 R11 R13 270 ohms R9 150 000 ohms R14 1 000 ohm multi turn trimmer potentiometer R15 100 000 ohm linear taper slide or rotary type potentiometer see text R16 1 megohm trimmer potentiometer Miscellaneous S1 Spst lever or slide switch S2 S3 Normally open momentary action spst pushbutton switch SOI Chassis mount three contact ac receptacle T1 6 3 volt center tapped 100 mA minimum power transformer Printed circuit boards or perforated board with holes on 0 1 and suitable Wire Wrap or soldering hardware see text sockets for all DIP ICs and op tical isolators remote cable assembly see Note below suitable enclo sure s ac line cord with plug rubber grommets small diameter heat shrinkable or other insulating tubing heat sink see text spacers machine hardware hookup wire solder etc Note The special seven pin molded plug and 36 of five conductor cable required for the remote cable assembly can be ordered as Part No 215420 from Kodak Parts Ser vice Dept 716 724 7278 for 15 Alter natively see text for details One source for SC150M triacs is All Electronics 800 826 5432 which also sources many of the other components specified here Fig 1 Schematic diagram of basic Controller circuit Say You Saw It In Modern Electronics May 1990 MODERN ELECTRONI
186. ter chip Place a jumper on the JP1 pins Then place another jumper on the JP2 pins for the baud rate you wish to use Turn on power to the Program mer and note that all LEDs except the OKAY one for the ERASE func tion come on for about a second and then extinguish Using the Programmer Your Programmer is now ready to be put into operation Tooperate it con nect the Programmer to your com puter via either its Serial or Parallel Port using the appropriate cable In the case of the Parallel Port connec tion you simply unplug the cable from your printer and plug it into Pa rallel Port connector J3 If you are using the Serial Port arrangement bear in mind that the Programmer is designed to operate as a DCE device It uses a nine pin female type D connector that is di rectly compatible with nine pin COMM ports on most IBM PCs and compatibles The pin assignments and signal directions for Serial Port connector J2 are enumerated in Ta ble 2 If your modem or serial printer uses a 25 pin D connector you must make an adapter cableto use the Pro grammer with it Be sure when mak ing this cable that you check the defi nitions of the lines on your computer and match them with the correct lines of the Programmer You can operate your Program mer in either of two modes If jumper JPl in Fig 3 B is not bridging shor ting together the two contacts E 32 MODERN ELECTRONICS May 1990 A good way to show
187. th Apple s Macintosh computers From a technology point of view the most impressive new feature of the Laser Jet III is Resolution Enhancement One problem with any printer that uses dots to form characters is that these char acters often show some jaggedness While laser printers use extremely small dots that minimize these effects a close examination of laser output especially of extremely large or small type often re veals the dot heritage of this printing method The jaggies are more noticeable where a character curves or at the inter section of two lines such as in the valleys of letters such as y and x Two factors contribute to the jag gies The first is that all characters are made up of dots of the same size This dot size is most obvious where a character ta pers off to a point such as at a serif An other factor is that the dots are all placed in the same plane Curves are constructed by ramping the dots leaving several dots off successive lines This creates a stair step effect that can give a curved area a jagged appearance H P s Resolution Enhancement fills in the gaps with smaller dots smooth ing the ramps much like filling in a gap in a wall with spackle In the vertical mode 68 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics these smaller dots are created by lowering the power of the laser beam resulting ina smaller charge on the photoconduct
188. the IC R71A IC R7000 and IC R9600 ICOM expanding the horizons to bring you better technology today See the complete line of cuality ICOM receivers at your local authorized ICOM dealer today First in Commis CIRCLE 115 ON READER SERVI
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190. the rear panel and fasten it in place with a plastic strain relief or tie a strain relieving knot in it about 3 inches from the unfinished end on the inside of the panel Tightly twist together the fine wires in each line cord conductor and sparingly tin with solder Plug the conductors into the 120 VAC IN holes in thereceiver circuit board assembly and solder into place Note Check which conductor you plugged into the hole labeled NEUT in the trans mitter board Regardless of whether its insulation is smooth or ribbed plug the conductor with the same in sulation in the NEUT hole in the re ceiver board Now perform voltage checks to as certain that the receiver module has been properly assembled For this you need a dc voltmeter or a multi meter set to the dc volts function Clip the common lead of the meter to a convenient circuit ground point on the receiver circuit board assem bly such as the metal tab on the bridge rectifier assembly When you perform the following voltage tests make absolutely certain that you do not touch the primary circuit of 77 Potentially lethal 117 volt ac line po tential is present in this portion of the circuitry When you are ready to perform the eer M M MM May 1990 MODERN ELECTRONICS 47 a L RECEIVER Semiconductors BR1 50 PIV bridge rectifier
191. tiasorarive ine Descramblers Why Pay a High Monthly Fee Brook NY 1780 For FREE Catalog Call or Write COMPUTERS RA 3 BOX8C Barton Vermont 05822 CABLE CONNECTION ENGINEERING Software PC MSDOS Phone 802 525 3458 FAX 802 525 3451 1304 E CHICAGO ST SUITE 301 Hobbyists Students Engineers Circuit De ALGONQUIN IL 60102 sign 49 PCB Layout 99 Logic Simulation CIRCLE NO 158 ON FREE INFORMATION CARD 708 658 2365 29 Mathematics 39 Circuit Analysis 29 No Illinois Orders Call or Write For Free Catalog 614 491 0832 BSOFT SOFTWARE 444 Colton Road Columbus OH 43207 SURVEILLANCE p iei LOTTERY Software Our sophisticated but TELEPHONE 4 F easy to use program can make your dream LE normal functioning telephone come true IBM PC COMPATIBLE 29 Only VoU is I gi de Md a nr n using a check money order POLYWAY BUSINESS secret code and never be detected Range Unlimited INC P O BOX 11086 NEW BRUNS LISTEN ELECTRONICS SI Eia Muskogee OR 24401 WICK NJ 08906 1 800 633 TAPS ee IEEE ABSOLUTELY LOWEST PRICES on com puters software and accessories guaran CABLE TV BOXES teed Write for free information SEABIRD Descramblers Converters 4K Militia Drive Lexington MA 02173 FREE CATALOG BUSINESS OPPORTUNITIES TRANS WORLD CABLE CO LEARN to Clean Repair Fax Machines 12062 Southwest 117th Ct Suite 126 Huge new market Earn 85 hour No experi Miami Florida 33186 ence necessary
192. tion Fortun ately the user manual which is 16 sheets of paper stapled together and printed on front and back does a bet ter job of getting you started The manual explains that the pro gram simulates an RPN reverse Pol ish notation calculator for complex numbers To enter a complex num ber you simply type in the real part hit the space bar type in the numeri cal value of the imaginary part and press the Enter key The program then puts the number on the top of the Fig 4 When you store a variable in CMPCALC4 it appears at the bottom of the screen with its name beside it M UQCDMEUEENUEL CL Iu GC E ZEN HLcW e wc M CC es e May 1990 MODERN ELECTRONICS 21 In the accompanying article we re viewed three math programs that runon the IBM PC and compatibles and in the follow up article also reviewed a new scientific calculator from Hewlett Packard If you re in market for one of these or a competing product it s likely that you re interested in some or all of the features listed inthe Table presented here The Table gives a snapshot of how each of the products reviewed here stack up against each other Each fea ture is given a rating from 0 to 5 where Oisthe lowest rating and 5 is the highest To give you an example of how we rated each feature take a look at Pro grammability The HP 48SX has a fine programming language so it re ceives a 5 MathCAD and C
193. tions for electronics such as a file with electronics units or a file full of electronics equations but these can be entered by the user Derive does many things includ ing symbolic math and does them well Although it lacks programming features it s still an excellent pro gram for general mathematical use and should be seriously considered for specific electronics work too CMPCALC4 A calculator for complex computing CMPCALC4 is a new program from UDH Enterprises 1000 E William St Suite 100 Carson City NV ENTER CMPLX NO OR ORDER H FOR HELP 2 0000080G000E AA 3 67800000000E 80 5 0000000000E 08 5 0000000000E 88 4 00000GGGOQGE OQ0 3 00000900000E AA 2 0000000000E G0 3 678000G00G0E 00 O EE L RET rr RR o RR NE EE RR Ws pu E M E E EE 89701 that turns your PC into a complex number calculator The program which has a suggested re tail price of 39 95 was written by an electronics engineer to assist in per forming analysis of feedback cir cuits A subset of the program called CMPCALC3 is available free from the author for a 5 shipping and han dling charge CMPCALC4 Operation When you load CMPCALC4 a sin gle prompt line appears on your screen It says Enter Cmplx no or order H for help Entering a complex number such as 4 2i gives you an error message and re turns you to the prompt entering H gives you a help screen loaded with too much informa
194. to a videocas sette recorder a 3 5 inch program disk and user s manual Power for the Controller is pro vided by four AAA cells It draws less than 50 mA from the Amiga computer 180 plus 5 shipping CIRCLE NO 129 ON FREE INFORMATION CARD Magnetic Sensing Probe The Lil Devil Mag Probe from HUB Material Co Canton MA detects residual magnetism and tran sient current pulses glitches as fast as 10 milliseconds and identifies north and south poles in ac and dc powered solenoids relays and any other electromagnetic device There is no need to refer to a schematic dia gram when troubleshooting a device under test with the Lil Devil One just positions the probe tip close to the coil in the device A LED in the handle of the Lil Devil lights if the device is energized No electrical connection to the circuit or device under test is required 14 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics Two models are available The standard sensitivity model tests large and standard size solenoids and re lays The high sensitivity model tests the full range of devices down to subminiature reed relays CIRCLE NO 130 ON FREE INFORMATION CARD Indoor Outdoor Speaker Sonance s first box type weather re sistant Speaker system available in two models mounts in locations where an in wall speaker system would be inconvenient or inappro priate The Models SB30 and SB10 hav
195. too critically switch ing on an electrical appliance close to Continued on page 82 SSE SSS EE SEES SS EE eS a cmm eee OE Om oco May 1990 MODERN ELECTRONICS 43 EXTENDED Lt EHE Project The Extended Play Remote Control System Conclusion Operating and construction details for the receiver module system checkout and installation and use By Crady M VonPawlak ast month in Part of this article we discussed the theory of operation con struction and initial checkout of the transmitter portion of the Extended Play Remote Control System This month we conclude with the receiver module system checkout and instal lation and use of the full system The system enables one to control a VCR or stereo music system with his infra red hand held remote controls from another location without running connecting wire or cables Thus one can watch or listen on a set in another room while maintaining full control of the device in the main room About the Circuit The complete schematic diagram of the receiver circuitry is shown in Fig 7 Capacitor C6 and resistor R9 pro vide capacitive coupling of the signal impressed on the ac line by the trans mitter to coupling transformer 72 This RC network plays a secondary role attenuation of large power line spikes and transients that can enter T2 or power transformer 77 The receive side of 72 pins 5 and 6 is impedance matched to the ac power lin
196. tor should be placed as near as possible to pins 8 and 16 of C3A during construction Slide or toggle switch S7 and push button switches S2 and S3 permit you to manually set up and operate the system As mentioned above LEDI gives an indication of the brightness of the lamp in the projector Power to the projector is visually indicated by LED 2 lighting while a slide change is indicated by LED3 A lightweight five conductor cable of reasonable length up to 100 yards is possible with this Controller oper ates the projector from a remote point By including optical isolator C6 as shown in Fig 2 close to the projector this control cable does not have to carry 117 volt ac line power Inserted in the cable close to the pro jector a small box serves as the junc tion that allows three of the cable s five conductors to join directly to the common conductor yellow insula tion forward thick conductor green insulation and reverse conductor May 1990 MODERN ELECTRONICS 39 The output at IC2 Pin 1 switches from full on to full off at the crossing points Voltage set by R15 Output from IC1 Pin 7 Output at Pin 1 ee a m When the voltage set by R15 is raised The output at IC2 Pin 1 is fully on for longer periods Voltage set by R15 Output from IC2 Pin 7 e a Output at Pin 1 When the voltage set by R15 is lowered The output at IC2 Pin 1 is full
197. ue mode This feature is standard in most PostScript applications and its inclusion in PCL 5 brings the LaserJet III closer to meeting the requirements of both PCL and PostScript users If you simply must have PostScript compatibility in your PCL printer H P will be introducing a PostScript emula tion in a few months If you can t wait or don t want to spend the thousand or so dollars that this cartridge will cost you can gain PostScript compatibility by us ing one of the software products current ly available such as UltraScript Go Script or Freedom of the Press These cost considerably less but require that you first print a file to disk then process the file through the software package to print it As you might expect this takes consid erably more time than just printing the file with a hardware emulation cartridge Pacific Data Products makes a Post Script cartridge for the Series II and IIP laser printers so I wouldn t be at all sur prised to see these companies bring one out for the LaserJet III if they haven t al ready done so by the time this review ap pears Pacific s cartridges for the IIP and Series II cost under 700 so if they follow the current pricing it will besever al hundred dollars less than an equivalent unit from H P An additional emulation cartridge will give the LaserJet III Epson FX and IBM Proprinter compatibility A hardware option will add AppleTalk to the printer easing its use wi
198. ugraphics Intellifont technology that has been incorporated into the new PCL 5 version of H P s Printer Control Language There are several other major benefits that PCL 5 provides AutoFont support which provides the font metrics for outline and bit mapped fonts directly to an application that supports this tech nology and most major software ven dors have committed to do this elimin ates the user having to provide this infor mation when installing new applications or fonts Recently Al Burawa Managing Edi tor of ME and I were discussing the IIP printer Al made the comment that he wished the IIP could also make use of the HPGL graphics language it would make the printer particularly appropriate for CAD applications such as producing board layouts and schematics Well Al maybe H P has our phones tapped be cause this feature has been implemented in the LaserJet III PCL 5 provides vector graphics for the first time on the LaserJet Vector graphics is a method of produc ing graphics by drawing a line between two previously defined points This capa bility is achieved by incorporating HP GL2 thegraphics language used in H P s plotters into PCL 5 While it will take software vendors some time to make use of this feature eventually this feature will provide many of the special effects now available only on PostScript printers Another feature of PCL 5 is the ability to overlay images in either a transparent or opaq
199. upon as a last resort few homes actually need this modifica tion it will benefit any carrier cur rent accessories you presently own Now that you have established an IR liak via the ac wiring in your home some interesting possibilities are possible For example you can use the Extended Play system as a LL SL SSS SS SL mr ee ee SS SS SS lM LM M M 04 ee burglar alarm accessory a remote appliance controller and more as suming you come up with suitable in terfaces Add to this list lights heat ers fans and air conditioners all of which should be able to be controlled with the proper interfaces Even a personal computer with an IR trans mitter adapter is not inconceivable With a bit of ingenuity on your part you can probably think up dozens of other control applications for the Ex tended Play ME SUBSCRIBE NOW M ORE amp SAVEI T H A N ui Ilse AD BEI iu Surround Sound Processor by a BL m Heathkit Surround yourself with a vast assortment of kit or ready to use electronic products from the FREE Heathkit Catalog The Heathkit Catalog contains innovative home theater components amateur radio and weather equipment laptop computers self Study electronics courses and challenging starter kits for the first time builder Order your FREE Heathkit Catalog NOW 1 800 44 HEATH 1 800 444 3284 Name Address State Send to Heath Company Dept 079 894 Bent
200. urce select a 12 volt dc relay Also make sure that the rated coil current is less than 200 milliamperes If you do not know the coil current rating calculate it using the known or measured dc coil resis tance the most commonly listed relay specification from the formula Loi Vc yR i Continued on page 77 D2 D3 Fig 10 Diodes can isolate the 555 output from transient pulses in the external load circuit May 1990 MODERN ELECTRONICS 57 Wil ELECTRONICS NOTEBOOK NN Experimenting with Incandescent Lamps By Forrest M Mims III The ancient incandescent lamp may seem to be rather low tech for a magazine with the name Modern Electronics Actually though some very significant advances have been made in the field of incandes cent lamps about which I shall have more to say later I ll then present some experiments and circuits you can try that may cast a new light on the versatility of an antique electronic component we all take for granted First let s pause for a brief review of the history of the inven tion of the incandescent lamp The Invention of the Incandescent Lamp Though Thomas Edison is generally credited with the invention of the incan descent lamp other inventors also played a prominent role in this area In 1802 En gland s Sir Humphry Davy demonstrated that an electric current passing through a thin strip of platinum would cause the metal to emit a visible glow All modern incandesce
201. visible re sponse of the human eye is certainly no coincidence Tungsten Filament Lamps The simplest tungsten lamp consists of ei ther a straight or coiled tungsten filament installed in an evacuated glass envelope The filament begins to emit a dimly visi Say You Saw It In Modern Electronics ble red light at a temperature of around 1 000 K In normal operation the fila ment of an evacuated tungsten lamp is typically heated to a temperature of 1 800 to 2 200 K The peak wavelength of an evacuated tungsten lamp with a filament temperature of 2 000 K is around 1 5 mi crometers in the near infrared Only around 5 percent of the optical radiation emitted by the filament is visible light the remainder is invisible infrared If the filament is operated at a temper ature higher than about 2 200 K the rate of tungsten evaporation from it will be come so high that the inside of the enve lope will quickly become coated with an opaque film of tungsten atoms Once I mistakenly applied far too much current to a miniature incandescent lamp The filament exploded in a brilliant flash and coated the inside of the glass envelope with a shiny film of tungsten Tungsten lamps can be operated at a temperature higher than 2 200 K if the en velope is filled with an inert gas such as argon or krypton which reduces the evaporation of tungsten from the fila ment The upper limit is 3 600 K the melting point of tungsten Since gases condu
202. w It In Modern Electronics used with a 555 timer in A current source and B current sink modes Output is high however a potential appears at pin 3 current flows in the LED and the LED turns on In Fig 7 B the opposite connec tion is shown Here the LED is wired between the OUTPUT terminal and V causing the output of the 555 to sink current When the output is low the cathode end of the LED is essen tially grounded through a small re sistance so the LED is turned on When the output is high the poten tial at both endsof the LED is closeto V Thus with no differential volt age between cathode and anode no current flows through the LED and the LED is off In both Fig 7 examples the resis tor in series with the LED limits the current flowing in the LED For most unmarked LEDs maximum safe cur rent is 15 mA 0 015 A Therefore you should set the value of R2 to a value of V 0 015 or greater When the current through the load exceeds the 200 milliampere output pcc c 4 O NO K1 Current source Fig 9 Current sink and source details of a 555 used to drive relays Say You Saw It In Modern Electronics Fig 7 Light emitting diode load capacity of the 555 you can add an external transistor switch as illus trated in Fig 8 to handle the greater current Theoutput of the 555 is used to turn on and off the transistor In Fig 8 A an npn transistor version is shown
203. y gt R11 C3 22 100k roe R12 cs c6 c7 4 7k R10 ik 93 2N3906 Ei RSL 6 8k 1N5819 ko Q2 2N3904 R4 1 5k R1 ULC 1 5k f 74HC 14 vee i LA R7 100 i U1A Fis a L J 3RBST gt ci 74HC14 Fig 4 Schematic details of the Programmer s A Dc to DC Converter and B Reset Controi circuits 34 MODERN ELECTRONICS May 1990 Say You Saw It In Modern Electronics Table 3 Modem Mode Menu Screen U pload ASCII S1 S9 file to buffer P rogram EPROM from buffer V erify EPROM against buffer X Buffer display ASCII hex Y EPROM display ASCII hex is the same as the object file loaded into the RAM buffer If verification is successful the green VERIFY OKAY LED turns on If the verify step fails the red VERIFY FAIL LED turns on In Modem mode the jumper is present on JP and uses only the Seri al Port To use this option your computer must be loaded with a com munications program capable of handling ASCII file transfers Modem mode allows you to inter act with the Programmer via the menu shown in Table 3 Bear in mind that this is not an automatic mode You must tell the Programmer to perform each step of the procedure These steps normally are 1 Upload the ASCII S1 S9 file to the buffer 2 Program the on chip EPROM from the buffer 3 Verify the data contents of the EPROM by comparing them with the data file stored in the buffer Though Modem mode
204. y on for shorter periods Output from IC2 Pin 7 Voltage set by R15 t Output at Pin 1 Fig 4 Pulse waveforms at pin 1 of IC2 for various settings of fader control R15 top at mid position center near top of control and bottom near bottom of control white insulation of the projector s molded plug and cable The timing sequences for the com plete Controller circuit are shown in Fig 5 Figure 5 A details the timing for switching on the projector and fading the projector lamp to full brightness Figure 5 B details the timing for fading the projector lamp to full off changing the slide and switching off the projector Construction There is nothing critical about assem bling the Controller circuitry other than to observe the normal precau Hm oem eee E U M M M me s HU tions about isolating the 117 volt ac from the low voltage dc portions Therefore you can use printed cir cuit boards on which to mount and wire together the circuitry or perfor ated board that has holes on 0 1 inch centers and suitable Wire Wrap or soldering hardware Whichever way you go be sure to use sockets for all DIP ICs and optical isolators If you wish to wire your circuitry on printed circuit board use the ac tual size etching and drilling guides shown in Fig 6 Then wire first the main and then the smaller boards ex actly as shown in Fig 7 If you opt for
205. you how to use the Programmer described in the main arti cle is to step you through a sample as sembly language program Such a pro gram is that provided in Listing Com ments like the first line of the program begin with an asterisk The next eight lines in the program are examples of the EQU or equate directive which allows you to assign a name to a numerical value After this you can use the name instead of the value which makes the program easier to read For example consider the following two lines of code PIDDR EQU 00 CLR PIDDR The first line assigns the name PIDDR Port Data Direction Reg ister to the value zero The second line clears the data at address PIDDR in this case address 00 The same thing can be done with CLR 00 but using the name PIDDR gives clearer meaning to the intent of the code Equate directives are valuable pro gramming tools in that they help you to create an environment that uses fami liar names However equate directives generate no executable code The next directive you come to in Listing 1 is ORG or originate This directive tells the assembler where code should be placed in memory In Listing 1 the code would be assembled to start at location F800 which is the bottom of the internal EPROM for a standard 68701 microcomputer chip Executable code is divided into two parts These are an initialization section that begins at the label RESET and
206. you press Enter and the program moves it above the hori zontal bar that divides the screen This upper portion of the screen is known as the work area Each ex pression in the work area is given a number and the most recent entry is highlighted in reverse video The program s use of reverse video is interesting When you first enter an DpI MP A ur EN L HR C c SS H expression the entire entry is high lighted You can change the high light however with the cursor keys You can highlight a portion of an en try or you can move the highlight to another entry Eight of the menu choices directly affect entries in the work area Some choices such as Plot operate on high lighted entries or parts of entries For example if the equation y 2x 3 is highlighted and you choose Plot the program draws the graph of the line y 2x 3 However if you highlight only 2x the program draws the graph of y 2x Other choices such as Factor prompt you for the number of the equation that you want to work on When the work area is first dis played it is referred to as an algebra window This means that equations or expressions entered in the menu area are transformed to look like equations or expressions from a text book or journal For example when you enter an integral at the menu prompt you do it by typing INT fol lowed by a mathematical expression However when the program
207. you train with the professional closed For all the details about NRI s at home circuit television surveillance equipment Security Electronics training send the cou and high quality electronic home and auto pon today If the coupon is missing write to alarm systems included in your course NRI School of Electronics McGraw Hill Con Step by step vou learn by doing eval tinuing Education Center 4401 Connecticut uating your own security needs installing Avenue Washington DC 20008 Te amp NND NEED NEED GP NND lum GRUND GEN ee D D GUN C Gum 2 2 ee D IU Afr OF ELECTRONICS W Installing bome security systems like tbis closed circuit camera and monitor is just one way you can make money as a security electronics tecbnician ram M McGraw Hill Continuing Education Center Hi 4401 Connecticut Avenue Washington DC 20008 LT Check one catalog only bx A Air Conditioning Heating C Smoll Engine Repoir ond Refrigeration L Automotive Servicing CI Security Electronics C Robotics LJ Computers ond CI TWideolAudio Servicing l Microprocessors Basic Electronics Electricion Locksmithing 1 Nome M Ar l Address 1 City State SOE u i Accredited by the Notional Home Study Council For coreer courses approved under GI Bill check for details 4 950 AMAZING SCIENTIFIC amp ELECTRONIC PRODUCTS GRA1 ANT GRAVITY GENERATOR 10 00 w

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