HP 400E User's Manual
Contents
1. 2 5 2 5 3mV to 300V RANGES 10Hz _ 20Hz 2 54 2 5 ImV RANGE 10Hz 2 5 2 5 Frequency 1 1 Frequency 20Hz From 1 3 full scale to full scale only 10 Models 400E 400EL Input Impedance 10 megohms shunted by less than Models 400E 400EL ACCURACY full scale Reading IL LD 40Hz AC to DC CONVERTER OUTPUT 100Hz T awe 100Hz For 15 C to 40 C on ImV to 1 volt ranges only Models 400E 400EL Specifications Output Resistance 1000 ohms 5 Response Time 1 second to within 1 of final value for a step change AC Power 115 or 230 volts 10 50 to 400Hz 5 watts Temperature Range 0 to 55 C except where noted on accuracy charts External Battery Operation Terminals are provided on rear panel positive and negative voltages between 35V and 55V are required current drain from 50 to 75mA Weight Net 6 lbs 2 7 kg Shipping 8 ibs 4 kg Dimensions 6 1 2 in high 5 1 8 in wide 11 in deep 165 1 X 130 2 x 279 4 mm l 10MHZz 2 5425 2MHz _ 4MHz 5 1 5 500kHz 4MHz 10MHz 500kHz MHz 125 425 TUS TA 1 MHZ 4MHz 95 2 5 100kHz 0 4 0 1 1 1 Models 400E 400EL Section SECTION GENERAL INFORMATION 1 1 DESCRIPTION 1 2 The hp Mode2. Distortion 7 Max Max Positive Negative Depends on phase relationship between harmonic and fundamental NOTE Since the 400E EL is average responding and rms calibrated any _ distortion will affect the accuracy of the measurement Table 3 1 shows the errors caused by distortion ee a Ensure that 115 230 vac slide switch on the rear panel matches line voltage used and connect power to the instrument Mechanically zero the instrument using the procedure outlined in Paragraph 5 5 b To operate the Model 400E EL with battery power connect two 35 to 55 volt batteries as shown in Figure 3 1 Since the front panel LINE switch has no effect during battery operation the switch in Figure 3 2 can be used as a convenient method of disconnecting the batteries when the instrument is not in use Two 35 volt batteries will draw approximately 75mA and two 55 volt batteries will draw approximately 50mA BATTERY VOLTAGE ob oe 35 55 J 35 55 Ta 35 55V 35 55V ADORE EL B O461 Figure 3 1 External Battery Connection _ 3 1 Section III A aa L H WLETT PACKARI AQGEL AL VOLIMETER LD 400E Scale Indicates magnitude of applied signal in volts and dB Option 01 places the dB scale uppermost for greater resolution OdBm imW in 600 ohms 2 400EL Scale Indicates magnitude of applied signal in volts and dB DB scale is linear and voltage scales are logarithmic This ar
3. 28 To protect operating personnel the National Electrical Manufacturers Association NEMA recommends that the instrument panel and cabinet be grounded All Hewlett Packard instruments are equipped with a three conductor power cable which when plugged into an appropriate receptacle grounds the instrument The offset pin on the power cable three prong connector is the ground wire 2 9 To preserve the protection feature when operating the instrument from a two contact outlet use a three prong to two prong adapter and connect the green pigtail on the adapter to ground 2 10 INSTALLATION 2 41 The Model 400E EL is fully transistorized _ therefore no special cooling is required However the instrument should not be operated where the ambient temperature exceeds 55 C 131 F or the relative humidity exceeds 95 2 12 BENCH MOUNTING 2 13 The Model 400E EL is shipped with plastic feet and tilt stand in place ready for use as a bench instrument 2 14 INSTRUMENT CASE 2 15 The 400E EL can be placed in a rugged high impact plastic case hp 11076A The instrument can be operated stored or carried in this splash proof case A dual purpose tilt stand also serves as a carrying handle Storage space is located at the rear of the case and in the front lid 2 16 RACK MOUNTING 2 17 The Model 400E EL may be rack mounted by using an adapter frame hp Part No 5060 0797 The adapter frame is a r
4. Model 400E EL described in this manual P l ll If a letter prefixes the serial number the instrument was manufactured outside the United _ States E Models 400E 400EL Section If SECTION II INSTALLATION 2 1 INTRODUCTION 2 2 This section contains information and instructions necessary for the installation and shipping of the Model 400E and 400EL voltmeters Included are initial inspection procedures power and grounding requirements installation information and instructions for repackaging for shipment ae 2 3 INITIAL INSPECTION 2 4 This instrument was carefully inspected both mechanically and electrically before shipment It should be physically free of mars or scratches and in perfect electrical order upon receipt To confirm this the instrument should be inspected for physical damage in transit Also check for supplied accessories and test the electrical performance of the instrument using the procedure outlined in Paragraph 5 7 If there is damage or deficiency see the warranty on the inside front cover of this manual 2 5 POWER REQUIREMENTS 2 6 The Model 400E EL can be operated from any source of 115 or 230 volts at 50 to 400Hz or from two 35 to 55 volt batteries connected to the rear panel BATTERY terminals The 115 230V slide switch on the rear panel selects the desired line voltage Power dissipation is 5 watts maximum 2 7 GROUNDING REQUIREMENTS
5. and Q16 connected in cascade A2R59 in the base circuit of A2Q15 zeroes the output dc level at the ac output 4 22 POWER SUPPLY 4 23 The power supply produces regulated 26 volts and 26 volts Breakdown diode A2CR7 establishes a reference voltage of 6 98 volts Part of the power supply output is applied to the base of A2Q2 and A2Q2 senses the difference between the supply output and the reference If the output voltage changes the emitter to base voltage of A2Q2 will change and the output of A2Q2 will change the current through A2Q1 the regulator 4 24 The negative regulator A2Q3 and A204 uses the 26 volt output as a reference Consequently the negative supply is dependent upon the positive supply
6. 00E The dB scale reads from 15 to 2 instead of from 12 to 2 and is placed at the top of the scale for better resolution 3 44 400E E WITH OPTION 02 3 15 Option 02 adds a relative reference adjustment Models 400E 400EL to the 400E EL This adjustment allows a meter indication to be varied by 3dB Use the REL REF adjustment to set the meter at any convenient reference OdB for example in order to make relative readings easier When the REL REF adjustment is in the fully clockwise ABSOLUTE position it has no effect on the meter accuracy 3 16 In all other respects operation of a Option 02 instrument is the same as operation of a standard Model 400E EL 25 ne A a RET T90 pepr 1 5 4 fp rept bem pz d si K H L FE W a i aa a 1 BR R RR AHHH RE Y BR N K 3 51 Sh 1 6 t O on ee 5 METER CORRECTION DBM EDE ppp pg MR 65 KL N 8 51 OTEN pE D K 9 ARR P CS 9 gt PR n et 9 5 HI L ERE a H E 9 R 8 1 RE R R E 9 D ve Rp m Wa Ee R S S T HT T oaan HE a oo T moetet i Sea aes ene et A B G D EE eo S SATA D E GE nd a Na Ri EENEE Pm ee SB SE E Ne E ee 0 9 maat RR HR Tg LET TT TTT NTT a D 2 HE HH E 8 8 H DS N H R 5 HB3 NR 9 TOE O K tap 9 Ws nt EO 0 R B E 85 LE NN pR amg E R TO 9 A RUE N P R EO A paien a prett 51 ER Si ces S Cet em N RRR L aR H 9 a 1 gain O R K 1 R 851 LET ems mR VOA PA 9 R Seen HES E E R 8 Y Haag
7. EES p DR NR b A E Stat vE g HE 8 S 0 2 Ws 9 SS R A 9 9 3 5 1 O eS L 9 8 iaeo G H Wal RRS R R E WR p RO BET H 0 SN Y E S B 9955 S A A NE Be OE an sa PS N R ka 9 LEELLE DNN ODE I UA DA E D A DADDA SONN DON DA tH DORRAS DAN DDA VIE DA T D IOAN DA ODA AD 9 9 A H R 8 1 ee ee 19 9 A EA 1 A R H G aes Se ORANE E R e D E meh ERI E CENT O Se a S RR E Ped tt S S mas NR 59 SE 91 TE STON P SA 9 Z RN YD ES 5 B 1 pgn BR G A GI 20 100 IMPEDANCE OHMS R men ar EE ST LNTH LL A pap R ES 9 9 R R MD EEE H 9 9 HRH HRL WR ST E OW RRR WEEN HNN m A E 8 251 BERT S S BRT iK 7D 8 047T Figure 3 3 Impedance Correction Graph 34 Models 400E 400EL Section VY SECTION IV THEORY 4 1 GENERAL 4 2 The 400E EL is a solid state average responding rms calibrated voltmeter It also has applications as an ac to de converter and a wide band amplifier Figure 4 1 shows a simplified block diagram of the instrument 4 3 When relay K1 is closed the input is not attenuated and when K2 is closed the input is attenuated by 50dB On the 0 001 through 1 volt ranges KI is closed and K2 is open K2 is closed and K1 is open on the 3 through 300 volt range The entire Input Attenuator assembly is shielded and the relays are operated remotely by voltages applied through the RANGE switch Variable capacitor A1C2 is adjusted on the 3 volt range with a 3 volt 100kHz input in order to shap
8. HP 400E 400EL Fn cies wasters ESE OSE ANY RETAIN SEES EF OPT E SNE A G mi m RATING AND SERVICE MANUAL AC VOLTMETER 400E 400EL ili HEWLETT jh iA K L PACKARD 9 anes rane raen Eeee nro SEMAN ORDA BEETS arna emi ANA HE EI a perdra e Hini e C 7 9 71300579 00 dH a i R OPERATING AND SERVICE MANUAL hp PART NO 00400 90606 MODELS 400E 400EL AC VOLTMETER Serials Prefixed 536 Appendix C Manual Backdating Changes adapts manual to Serials Prefixed __ 536 04854 and below and 532 0 Copyright Hewlett Packard Company 1966 P O Box 301 Loveland Colorado 80537 U S A Printed May 1969 Section Table 1 1 Voltage Range mV full scale to 300V full scale in 12 ranges dB scale 10 to 2dB 10dB between ranges a Frequency Range 10Hz to 1OMHz Calibration Responds to absolute average value of applied signal calibrated in rms volts 25pF on the ImV iV ranges and 10 megohms shunted by less than 12pF on the 3V 300V ranges Amplifier AC Output 150mV rms for full scale meter indication output impedance 50 ohms 10Hz to 1OMHz 105mV on the ImV range Accuracy 10 10Hz to 4MHz AC DC Converter Output 1Vde output for full scale meter deflection linear output for Model 400E EL 3mV to 300V RANGES 10Hz 40Hz 2 5 2 5 Frequency imV RANGET Frequency 10Hz
9. Hz and A2C28 is adjusted at 1OMHz 4 7 The DC Output is a 0 1 volt level that is proportional to meter deflection R2 is adjusted to calibrate the de output The AC Amplifier samples the ac feedback and generates 0 to 150mV ac output that i is directly proportional to meter deflection 4 8 SCHEMATIC DESCRIPTION See Figure 7 I o 4 9 IMPEDANCE CONVERTER METER BRIDGE AC OUTPUT AMPL Figure 4 1 Simplified Block Diagram Section IV Models 400E 400EL sasao CURRENT DURING NEG HALF CYCLE me CURRENT DURING POS HALF CYCLE te S 00E EL 8 0635 4 A U r FEEDBACK Figure 4 2 Meter Bridge 4 10 The impedance converter located on the main voltmeter board A2 matches the high impedance of the input attenuator to the relatively low impedance of the Post Attenuator Breakdown diodes A2CRI7 and 18 bias diodes A2CR9 and 10 at 5 and 5 volts respectively A2CR9 and 10 limit the input to 10 volts peak to peak providing overload protection Breakdown diodes A2CR20 and A2CR21 stabilize the bias voltages on A2Q5 Fuse A2F1 protects the instrument against destructive overloads 4 11 A field effect transistor A2Q5 is used in the input stage of the impedance converter because of its characteristically high input impedance and good frequency response The output is taken from the emitter circuit of A2Q7 and applied to the post 4 2 attenuator and then applied to the meter amplifier _ The solid black l
10. ack frame that accepts any combination of submodular units It can be rack mounted only For additional information address inquiries to your hp Sales and Service Office See Appendix B for office locations 2 18 COMBINATION MOUNTING 2 19 The Model 400E EL may be mounted in combination with other submodular units by using a Combining Case hp Model 1051A or 1052A The Combining Case is a full module unit which accepts various combinations of submodular units Being a full module unit the combining case can be bench or rack mounted and is analogous to any full module instrument _ 2 20 REPACKAGING FOR SHIPMENT 2 21 The following paragraphs contain a general guide for repackaging of the instrument for shipment Refer to Paragraph 2 22 if the original container is to be used 2 23 if it is not If you have any questions Section H l 7 7 Models 400E 400EL contact your local hp Sales and Service Office See purchased from your nearest hp Sales and E Appendix B for office locations Service Office E NOTE b Ensure that container is well sealed with If the instrument is to be shipped strong tape or metal bands to Hewlett Packard for service or l l l l repair attach a tag to the 2 23 If original container is not to be used proceed 7 instrument identifying the owner as follows and indicating the service or repair Ws 2 to be accomplished include the l a Wrap instrume
11. e the frequency response of the input Attenuator 4 4 The signal from the input attenuator is applied to the impedance converter The impedance converter is a unity gain feedback stabilized amplifier that matches the high Impedance of the Input Attenuator to the much lower impedance of the Post Attenuator 4 5 The Post Attenuator attenuates the output of the Impedance Converter by 10dB for each step of the RANGE switch On the 3 volt range the Post IMPEDANCE CONVERTER i i i i I L L I t j j 1 i H i L st rs d H Si ag ad AOOE EL B OGS4R OF OPERATION _ Attenuator is switched back to the 30dB position and then it attenuates 10dB per step on the higher ranges Variable capacitor S2C2 is adjusted on the 003 volt range with a 3mV 8MHz input to adjust the 8MHz response of the 003 volt range With a full scale input on any range except the 001 volt range the output of the Post Attenuator should be 3mV On the 001 volt range the output should be ImV 4 6 The Meter Amplifier is a four stage high gain amplifier utilizing both ac and dc feedback for gain stabilization The Meter Bridge connected in the ac feedback path of the meter amplifier converts the ac output of the amplifier to a de voltage proportional to its average value This dc voltage drives the meter A2C28 and A2R38 adjust the gain of the amplifier so that the meter will read rms volts A2R38 is adjusted at 400
12. ection IH Connect the rear panel DC OUTPUT terminals to a dc measuring device with a high input impedance The dec output resistance is 1000 ohms and if it is loaded the dc output signal will be inaccurate gt The de output is a O to I volt signal proportional to the percentage of 400E EL meter deflection Wide Band Ac Amplifier Paragraph 3 8 b Select approximate range of input on RANGE switch c Connect SIGNAL to be piai to INPUT terminals d When using the ac power source prevent ground loops by using a NEMA adapter on the oscilloscope counter or other instrument used with the 400E EL Keep leads as short as possible and shield the input of the ac voltmeter to minimize pick up a NOTE ___ Place a 1 kilohm shielded load across the DC OUTPUT if it is not being used when using the AC OUTPUT This is especially necessary on low ranges The gain of the amplifier depends on the RANGE selection On the 0 1 volt range and below the 400E EL amplifies the input and on the 0 3 volt range and above it attenuates the input On the 0 001 volt ranges the maximum output is 105mV On all other ranges the maximum output is 150mV Table 3 2 shows the ac amplifier gain for each range setting Table 3 2 AC ie Sot Gain 34 Section HI 3 12 4006 WITH OPTION 07 3 13 Operation of the 400E with Option OIl is essentially the same as operation of the standard 4
13. ines on the schematic show the signal path and the broken lines show the feedback paths A2R17 adjusts the dc bias of the impedance converter 4 12 METER AMPLIFIER 4 13 The meter amplifier amplifies its input signal _by a fixed gain on all ranges except the 00i volt range The amplifier itself is a four stage de coupled amplifier with a cascode coupled final stage A2Q12 and 13 De feedback is coupled from the emitter of A2Q12 back to the base of A2Q9 Breakdown diodes A2CR12 13 and 14 establish fixed de bias levels in the amplifier Models 400E 400EL 4 14 The output from the collector of A2Q13 is coupled through the Meter Bridge and fed back to the emitter of A2Q9 A2C28 in the feedback circuit adjusts the amount of feedback at the high end of the frequency range and A2R38 adjusts the feedback at the low end This calibrates the amplifier gain at both ends of the frequency range A2R44 45 and 72 are switched into the feedback circuit on the 0 001 voit range boosting the gain on that range A2R44 adjusts the gain on the ImV range with a 400Hz input A2R31 adjusts the dc bias level of the amplifier 4 15 METER BRIDGE 4 16 Figure 4 2 shows a partial schematic of the Meter Bridge The meter bridge rectifies the ac amplifier output and supplies the de current to drive the meter In order to use part of the meter bridge output as the rear terminal de output the meter has to be referenced to gr
14. ls 400E and 400EL are versatile ac voltmeters and dB meters Both models can be used as ac to de converters or wideband amplifiers The Model 400E is primarily intended for voltage measurements whereas the Model 400EL is primarily a dB meter However both meters indicate both volts and dB The 400E has a linear ac scale with a logarithmic dB scale underneath and the 400EL has a linear dB scale with a logarithmic ac scale underneath Since the difference in scales is the only difference between the two instruments this manual will use the term 400E EL in reference to both instruments 1 3 Figure 1 1 shows both the Model 400E and the Model 400EL Table 1 1 is a list of specifications 1 4 OPTIONS AVAILABLE 1 5 OPTION 01 400E ONLY 1 6 Option 01 places the dB scale uppermost for greater resolution when making dB measurements 1 7 OPTION 02 1 8 Option 02 adds a relative reference adjustment to the 400E EL The REL REF control allows a continuous reduction in sensitivity by a maximum of 3 dB in order to make relative voltage or dB measurements 1 9 INSTRUMENT AND MANUAL IDENTIFICATION 1 10 Hewlett Packard instruments are identified by a two section eight digit serial number 000 00000 If the first three digits of the serial number on your instrument do not agree with those on the title page of this manual change sheets supplied with the manual will define differences between your instrument and
15. nt in heavy paper or plastic S model number and full serial before placing in an inner container number of the instrument In any i correspondence identify the b Place packing material around all sides of instrument by model number serial instrument and protect panel face with number and serial number prefix i cardboard strips 2 22 If original container is to be used proceed as c Place instrument and inner container in a follows heavy carton or wooden box and seal with strong tape or metal bands a Place instrument in original container if available If original container is not l d Mark shipping container with DELICATE available a suitable contdiner can be INSTRUMENT FRAGILE etc 2 2 os Models 400E 400EL Section III SECTION Ill OPERATING INSTRUCTIONS 3 1 INTRODUCTION 3 2 The Model 400E EL is primarily an ac voltmeter and dB meter but it can be used as an ac to de converter or as a Wide band amplifier 3 3 This section explains the controls of the 400E EL and outlines the operating procedures for each mode of operation 3 4 LOCATION OF CONTROLS AND _ INDICATORS 3 5 Figure 3 2 shows the location of each of the 400E EL controls and explains the function of each 3 6 OPERATING INSTRUCTIONS 3 7 STANDARD 400E EL 3 8 Ac Voltmeter Table 3 1 Effect of Distortion on Average Responding Meter pE ERROR Fundamental Harmonic
16. ound Transistor A2Q14 references the meter to ground 4 17 During the positive half cycle conducts Part of the current solid line goes through A2C34 into the feedback path and part of the current goes through A2R53 and the meter to ground The current through A2R53 turns on A2Q14 and A2Q14 draws current from the positive supply The current from A2Q14 goes through A2C36 into the feeback path The current through A2Q14 and A2C36 is equal to the current drawn through the meter so the current out of the bridge i is a to the current into the bridge 4 18 During the negative half cycle conducts and draws current from the feedback path dotted line Part of the current goes through A2C36 A2CRIS A2CRI6 Section IV and A2CRI6 into the amplifier and part goes through A2R53 and the meter to ground The current through A2R53 turns on A2Q14 and the current from A2Q14 goes through A2R54 and A2CR16 to the amplifier Again the current through the meter equals the current through A2R54 and the current into the bridge equals the current out 4 19 Transistor A2Q14 replaces current drawn by the meter so the meter bridge is kept floating while the meter is referenced to ground The dc output taken across A2R65 and R2 is also referenced to ground 4 20 AC OUTPUT CIRCUIT 4 21 The ac output circuit isolates the meter bridge and amplifier from the ac output load It consists of two emitter followers A2Q15
17. range of signal to be measured DO NOT APPLY MORE THAN 600 VOLTS TO INPUT DO NOT OVERLOAD THE 001 THROUGH 1 VOLT RANGES WITH MORE THAN 300 VOLTS AT FREQUENCIES BELOW 300kHz OR WITH MORE THAN 64 VOLTS AT FREQUENCIES ABOVE 300kHz IF ANY OF THESE OVERLOADS ARE EXCEEDED THE INSTRUMENT MAY BE DAMAGED e Connect signal to be measured to INPUT terminals and read the rms voltage on the scale 3 9 DB Meter a To make a dB or dBm measurement follow steps a through e in Paragraph 3 8 and add the scale reading to the RANGE setting For example If the scale reading is 1 5 and the RANGE is 30dB the final measurement is 28 5dB The 400E EL dB scale is calibrated in dBm OdBm is equivalent to 1 milliwatt dissipated by a 600 ohm load Consequently any dBm measurements must be made across a total impedance of 600 ohms Measurements across Other impedances will be in dB but not dBm To convert a dB reading to dBm use the Impedance Correction Graph Figure 3 3 For example To convert a 30dB reading made across 50 ohms to dBm locate the load impedance on the bottom of the graph Follow the impedance line to the heavy black line and read the meter correction at that point The correction for 50 ohms is 10 5dBm and the corrected reading is 40 5dBm 3 16 Ac to De Converter a Follow steps a through e in Paragraph 3 8 341 a Follow tumon steps a through c in GAIN RANGE GAIN S
18. rangement allows better resolution for dB reading 0dBm 1mW in 600 ohms to be iania REL REF Adjust Option 02 Varies indication on meter by 3dB Fully clockwise ABSOLUTE position retains full meter indication This control is used to vary meter indication with a given input in order to make relative readings easier RANGE Selector Selects full scale reading of meter DB reading on scale adds e vi dp mewLerTeneKaan Gar d 3 AC INPUT BNC input jack connects nain algebraically to dB iung of RANGE selector Models 400E 400EL 3985 VOC 400K AC VOLFMETER D Line ON Toggle Switch Applies primary power 7 LINE Indicator Lamp Indicates application of primary power 8 FUSE 1 8A Protects instrument against current overload 115 230 Volt Slide Switch Selects ANS or 230 volts ac for line operation _ 8 PRIMARY POWER CONNECTOR Line voltage is applied through this connector AC OUTPUT Ac amplifier output Output impedance is 50 ohms 021 DC OUTPUT Ac to de converter output De voltage is proportional to percentage of meter deflection Output eee is 1000 ohms 00 BATTERY VOLTAGE Terminals 400E EL may be powered by connecting two 35 to 55 volt batteries to these terminals Figure 3 2 Location of Controls and Indicators Models 400E 400EL c Turn line ON toggle switch to up position LINE lamp will glow d Select approximate
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