HP-412A-AR-Manual 电路图.pdf

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1、I . : HP Archive . . This vintage Hewlett Packard document was preserved and distributed by www. Please visit us on the web ! . . On-line curator: Tony Gerbic RadioFans.CN 收音机爱 好者资料库 I i i (r, , a i f OPERATING A N D SERVICE M A N U A L (HP PART NO. 00412-90003) MODEL 412A/AR DC VACUUM TUSE VOLTMETE

2、R SERIALS PREFIXED: 301-, 3160, 424-, 649- Copyright Hewlett-Packard Company 1961 P. 0. Box 301, Loveland, Colorado, 80537 U. S.A. 1 i O O T 2 9 - 5 Printod: NOV 1968 I RadioFans.CN 收音机爱 好者资料库 0 Model 4 12A h TABLE OF CONTENTS Section Page I GENERAL INFORMATION . 1-1 1.1 . Introduction . 1-1 1.7 . S

3、pecifications . I -I 1.Y . instrument and Manual Identification . 1-1 . Section I . ? Page 11 INSTALLATlON . 2-1 2.1 . Introduction . 2-1 2.3 . Initial inspection . 2-1 2.5 . Power Requirements . 2-1 2.7 . Grounding Requirements . 2-1 2.10 . lnstallatiori . 2-1 2.13 . Repackaging for Shipment . 2-1

4、i i 1 Section Page I11 OPERATING INSTRUCTIONS . 3-1 3.1 . Introduction . 3-1 3 . 3 . Low-Level Electrical Phenomena . 3-1 3.7 . Turn 1 volt at full scale; maximum current, 1 mA. (Full scale corresponds to 1 .O on upper scale.) Output Impedance: Less than 2 ohms at dc Noise: Less than 5 mV RMS on any

5、 range Drift: negligible GENERAL Isolation Resistance: At least 100 megohms shunted by 0 . 1 F between common terminal and case (power line) ground Common Mode Rejection: May be operated up to 500 Vdc or 130 Vac from ground Power: 115/230 V f10%, 5040 Hz, 35 W Dimensions: Cabinet Mount: 11-1/2 in. h

6、igh, 7-1/2 in. wide, 10 in. deep Rack Mount: 001 29-5 Model 4 12A 1-1. INTRODUCTION. Section I SECTION I GENERAL INFORMATION 1-2. The Hewlett-Packard Model 412A/AR DC Vacuum Tube Voltmeter is a multifunction instrument which measures the entire range of dc voltages, current, and resistance normally

7、encountered in electronic equipment. 1-3. The Model 412AIAR measures dc voltage from 1.0 mV full scale to IO00 V full scale in thirteen ranges arranged in a 1,3, 10 sequence. Voltmeter accuracy is 1% of full scale. The input circuit is isolated from the case and from power line ground. 14. The Model

8、 412AlAR measures positive or negative dc current from 1.OpA full scale to 1.0 A full scale with an accuracy of 2% of full scale. Current ranges are also in a 1, 3, 10 sequence. 1-5. Resistance measurement capability of the Model 412AIAR is from 1.0 ohm center scale to I 0 0 megohms center scale in

9、nine decade rangcs. Resistaiicc nieasureiiieiit accuracy is 5% between .3 and 3 on the resistance scale. 16. The Model 412AIAR has a dc aiiiylifier output voltage proportional to the input. Ainplificr giiiil is froiii -1000 to t1000, depending on range selected. 1-7. SPEC1 FlCATlO NS. 1-8. Complete

10、specifications for the dip- Modcl41 2AIAR are listed in Table 1-1. 1-9. INSTRUMENT AND MANUAL IDENTIFICATION. 1-10. Hewlett-Packard uses a twoscctioii cigltbdigit scrial number (OOO-00000). If the first tlircc digits of tlic scrial number of your instrumcnt do not agrcc witti thosc on tlic title pag

11、e of this manual, changc sliects supplicd with tlic manual will explain the diffcrenccs bctwccii your instrument and the Model 412AIAll dcscribcd in lliis manual. 412A-A-30188 Figure 1.1. Model 412A DC Vacuum Tube Voltmctcr 00 1 295 0 h cy P Y 4b 4 J Model 4 12A 2-1. INTRODUCTION. SECTION II IN STAC

12、LATIO N 2-2. Tliis section contains instructions necessary for installation of the Model 412AIAR DC Vacuum Tube Voltmeter. Included are initial inspection procedures, power and grounding requirements, installation information, and instructions for repackaging for shipment. 2-3. INITIAL INSPECTION. 2

13、-4. This instrument was carefully inspected both mechanically and electrically before shipment. It should be 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 test the clcctrical performan

14、ce of tlic instrument, using the procedure outlined in Paragraph 5-5. If there is damage or deficiency, see tlic warranty on the inside front cover of this manual. 2.5. POWER REQUIREMENTS. 2-6. The Model 412AIAR can be operated from any source of 115 or 230 volts at 50 or 60 Hz. The 115/230 V slide

15、switch on the rear panel selects the desired voltage. Power dissipation is approximately 35 watts. 2-7. G R 0 U N D I NG REQUl R EMENTS. 2-8. To protect operating personnel, the National Electrical Manufacturers Association (NEMA) recommends that tltc instrument panel and cabinet be grounded. This i

16、nstrument is equipped with a threeconductor power cable wluch, when plugged into an appropriate receptacle. grounds the instrument. The offset pin on the connector is tlie ground wire. 2-9. To preserve the protection feature when operating the instrument from a twocontact outlet, use a threeprong to

17、 two-prong adapter and connect the green pigtail on the adapter to ground. NOTE Operating the Model 412A/AR without grounding the third (power line ground) wire of the power cable will result in a zero offset of the meter and oscillation of the pointer. 2-1 0. INSTA 1 LATlO N. Section I1 2-1 I. The

18、Model 412A is intended for use as a bcncli instrument, having a top-mounted handle and rubbcr fcct. 2-12. The Model 412AR is intended for rack mounting. Front panel height is 5-7/32 inches. 2-13. REPACKAGING FOR SHIPMENT. 2-14. The following paragraphs contain a general guidc for repackaging of tlie

19、 instrument. Rcfcr to Paragraph 2-15 if the original container is to be uscd; 2-16 if it is not. If you have any questions, contact your local -lip- Salcs and Service Office. (SCC Appendix B for office locatiwis.) NOTE If the instrumcnt is to be sliippcd to I Icwlctt-iackard for scrvicc or repair. a

20、ttach a tag to tlic instrumcnt idcntifying the owncr and indicating tlic scrvicc or repair to be accomplislicd. lncludc tlic model number of tltc instrumcnt. In any corrcspondcnce, identify tlic instrumcnt by modcl numbcr, scrial numbcr prcfix, and scrial numbcr. 2-15. Place the instrumcnt in origin

21、al conhincr with suitable packing material and scat wcll with strong tapc or metal bands. If original containcr is not aviilablc, onc CBR be purchased from your ncarcst hp Salcs and Scrvicc Office. 2-16.lf original container is not to hc uscd, procccd as follows: a. Wrap instrument in hcavy papcr or

22、 plastic hcfurc placing in an inncr containcr. b. Place packing material around a11 sidcs of instrumcnt and protcct panel facc with cardhturd strips . c. Place instrument and inncr containcr in a hcavy carton or wooden box and scal wcll with strong tapc or metal hands. d. Mark shipping containcr “DI

23、LICATE INSTIWMENT,” “FRAGILE,” ctc. 00 1 29-5 2-1 hlodcl4 12A SECTION 111 0 PER AT1 N G 3-1. INTRODUCTION. 3-2. The -lip- Model 412A/AR DC Vacuum Tube Voltmeter nieasures dc voltages from 1.0 mV full scale to lo00 V full scale with an accuracy of 1% of full scale. Current measurement ranges are from

24、 0.001 mA full scale to 1000 mA full scale, with accuracy of 2% of full scale. The Model 41 2A/AR makcs resistaricc measurements from 1.0 ohm center scale to 100 megohms center scale. Resistance measurenicnt accuracy is 5% of reading between .3 and 3 on the ohms scale. A dc amplifier output is also

25、provided. Voltage gain of tlic amplificr is from -1000 to +1000, depending on range selcctcd. Amplifier output is 1 .O V at full scale. and maxinium current load is 1 .O mA. 3-3. LOW-LEVEL ELECTRICAL PHENOMENA. 34. Stray low-level electrical phenomena may cause error in low voltage measurements. Whe

26、n using the lower voltages of the Model 412A, consider the possibility of low-level voltages produced by thermoelectric effects, residual charges on capacitors, battery action, or flexing of coaxial cables, 3-5. The voltagc probe, currentlresistance lead, and common lead of the Model 412A/AR are all

27、 designed to have a very low thermoelectric effect with copper, the most commonly used conductor. However, some component leads such as transistors and reed relays may have leads made of such alloys as nickel-iron, which produce a thermoelectric voltage when joined with copper. Whenever possiblc, co

28、nnect tlic 412A leads to copper. If this is not possible, the voltage probe and common lead should both I n : conncctcd to the smic kind of inctal compncnt lead, and both connection points maintained at the same tc 111 pcra t urc. 34. To minimize tlic possibility of battery action when making low vo

29、ltage mcasurcments, make sure the 412A probe tip and common lcad alligator clip are clean. Also be surc tlic component leads or other points of connection are clean. The prcsence of sonic chemicals such as solder flux niay cause noticeable nieasiirement error due to battery action. NOTE Operating th

30、e Model 412A/AR without grounding the third (power line ground) wire of the power cable will result in a zero offset of the meter and oscillation of the pointer. IN STRU CTiO NS 3-7. TURN-ON PROCEDURE. Section 111 BEFORE CONNECTING PRIMARY POWER, MAKE SURE THE REAR PANEL 115/230 V SLIDE SWITCH IS SE

31、T TO THE POWER LlNE VOLTAGE TO BE USED. INCORRECT SETTING MAY RESULT IN DAMAGE TO THE INSTRUMENT. a. Make sure the proper fuse is installed for operation with the power line voltage to be used. A 0.6 A slow-blow fuse should be used for I IS V operation, and a 0.4 A slow-blow fuse for 230 V operation

32、. b. Connect to ac power and turn instrument ON. Allow a S-minute warm-up period. 3-8. VOLTAGE MEASUREMENT. a. Set FUNCTION switch to VOLTS, and select proper polarity. b. Set RANGE switch to desired range. If in doubt, set switch to high range and downrange as necessary. c. Connect VOLTS and COM le

33、ads across circuit or component, and read voltage. DO NOT OVEKLOAD THE INSTRUMENT. MOMENTARY OVERLOADS UP TO TEN TIMES FULL SCALE WILL NOT DAMAGE THE INSTRUMENT; HOWEVER, CURRENT SHUNTS, AND I N T E R N A L RESISTANCE S T A N D A R D S A R E NOT PROTECTED FROM EXTREME OVERLOAD. 33. CURRENT MEASUREME

34、NT. a. Set FUNCTION switch to MA. b. Set RANGE switch to desired range. If in doubt, select high range and downrange as necessary. 00 1 29-5 3-1 section 111 Resistance Range . c. Deenergize circuit to be measured. OpenCircuit Volts (at 1 on top scale) d. Connect 412A into circuit, using MA/OHMS and

35、COM leads. e. Energize circuit, set POLARITY switch for up-scale indication, and read current. NOTE When making current measurements, make sure there is no connection between the circuit common 6) and power line ground ( maximum rated load current is 1 .O mA. Load currents in excess of 1.0 mA (less

36、than 1000 ohms load 3-13. The Model 412A/AR DC Amplifier Output may be resistance) may cause errors in meter indication and used to drive devices such as an analog recorder to provide a amplifier gain. Amplifier gain is from +lo00 on the ,001 permanent record of measurements. Output level is 1 .O vo

37、lt range to -1000 on the loo0 range. 4 Y 00 1 29-5 I 3-3 Model 41 2A SECTION IV THEORY OF OPERATION 4-1. GENERAL. 4-2. The kp- Model 412AIAR uses a chopper-stabilized amplifier circuit to produce a meter indication proportional to the voltage, current, or resistance being measured. 4-3. BLOCK DIAGRA

38、M ANALYSIS. 44. Figure 4-1 is a block diagram of the Model 412AIAR. The following paragraphs describe operation of the various circuits. 4.5. RANGE AND FUNCTION SELECTION. 4-6. The Voltage Divider. Current Shunts, and Resistance Standards circuits provide a 0.9 mV output for full-scale input in all

39、ranges and functions. Full scale is defined as a reading of 1 on the top scale of the meter for all ranges. Simplified schematics of the switching circuits for all ranges and functions are shown in Figures 5-8 through 5-10, 47. FILTERS. 4-8. input filtering is provided to attenuate any ac components

40、 present in the input signal. The second fdter section filters the Demodulator output. RANOC SELtCllOW r Section 1V 4-9. MODULATOR, AMPLIFIER, DEMODULATOR, AN0 CHOPPER. 4-10. A light-beam chopper driven by a synchronous motor sets the Modulator/Demodulator frequency at 516 power line frequency. The

41、Modulator output is an ac signal proportional to the Model 412A input. The amplifier gain is stabilized at 1 ,111 by the feedback network, resulting in an output of 1 .O volt for a full-scale input. The Demodulator is synchronized with the Modulator so that the amplified ac signal is converted to a

42、steady dc, which is applied to the Cathode Follower. This voltage is the same polarity as the input signal. 4-11. CATHODE FOLLOWER AND POLARITY SELECTION. 4-12.The Cathode Follower drives the Meter and the DC Amplifier Output. Polarity selection provides upscale meter reading for either polarity inp

43、ut. The Polarity switch is disabled in the OHMS function. I Figure 4-1. Block Diagram 00 129-5 4-1 6 Section V Model 412A INSTRUMENT TYPE DC Voltage Standard Variable Line Transformer DC Voltmeter AC Voltmeter Oscilloscope Precision Resistors Oscillator Table 5-1. Test Equipment Required REQUIRED CH

44、ARACTERISTICS Range: 0-300V Accuracy: 0.1% Current Rating: 10 mA Output Voltage: to 127 Vac (or 253 Vac) Range: 1 V to 300 V Resolution : 10 mV Input Resistance: 100 M a Range: to 300 V Range: to 10 M a Sensitivity: 0.01 Vlcm Resistance: 1 10 100 1K 10 K 30K 5W 100K 1W 300 K 1/2 W 1M 10 M 100 M 10 M

45、 Accuracy : i 1.0% 2 1.0% f 1.0% f 1.0% +, 1.0% ? 0.1% 2 0.1% 2 0.1% 2 0.1% 2 1.0% 2 1.0% k 0.1% - Frequency : 60 Hz Output: IO V peak hp- 738BR Voltmeter Calibrator 1 Superior Electric Powerstat 3PF116 (for 1 15 V line) 3PF216 (for 230 V line) hp- 427A Voltmeter hp- 427A Voltmeter hp- 427A Voltmete

46、r hp 120B Oscilloscope Part Number: -hP- 08 1 I-OoFiO -hP- hP- 07574346 0757.040 1 -hp- 07574280 -hP- 07574442 Daven DAS-5 Dale MF-I Dale MFS-112 - h P 06984 16 1 0733401 7 - h P 0698-5049 -hP- -hP- 08 1 1-2475 -hp- 200CD Wide Range Oscillator Model 4 12A SECTION V MAINTENANCE 5-1. INTRODUCTION. 5-2

47、. This section contains information necessary to maintain the kp- Model 412A/AR. The following paragraphs describe the Performance Checks, Calibration Procedures, Troubleshooting, and Servicing Procedures. 5-3. REQUIRED TEST EQUIPMENT. 54. Recommended test equipment for maintaining and checking perf

48、ormance of the Model 412A is listed in Table 5-1. Test instruments other than those recommended may be used if their specifications equal or exceed the required characteristics. 55. PERFORMANCE CHECKS. 5-6. Use the following procedures to verify proper operation of the Model 412A. The 412A and test equipment should be operated at 115/230 Vac unless otherwise specified. A Performance Test Card is provided at the end of