IET 1433 SERIES User & Service 电路图.pdf

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1、1433 SERIES High-Accuracy Decade Resistor User and Service Manual PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT Copyright 2003 IET Labs, Inc. 1433 im/December, 2003 TEL: (516) 334-5959 (800) 899-8438 FAX: (516) 334-5988 IET LABS, INC. formerly manufacturer by GenRad 534 Main Street, Westbury, NY 11

2、590 RadioFans.CN 收音机爱 好者资料库 RadioFans.CN 收音机爱 好者资料库 iii WARRANTY We warrant that this product is free from defects in material and workmanship and, when properly used, will perform in accordance with applicable IET specifications. If within one year after original shipment, it is found not to meet t

3、his standard, it will be repaired or, at the option of IET, replaced at no charge when returned to IET. Changes in this product not approved by IET or application of voltages or currents greater than those allowed by the specifications shall void this warranty. IET shall not be liable for any indire

4、ct, special, or consequential damages, even if notice has been given to the possibility of such damages. THIS WARRANTY IS IN LIEU OF ALL OTHER WARRANTIES, EXPRESSED OR IMPLIED, INCLUD- ING BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTIBILITY OR FITNESS FOR ANY PARTICULAR PURPOSE. RadioFans.CN

5、 收音机爱 好者资料库 ii Contents WARRANTY .iii WARNING . v CAUTION. v Chapter 1 INTRODUCTION .1 1.1 Product Overview. 1 1.2 Accessories Included. 2 1.3 Accessories/Options Available. 2 Chapter 2 SPECIFICATIONS.3 Chapter 3 OPERATION.5 3.1 Installation. 5 3.2 Connections . 5 3.3 Dial Readout . 5 3.4 Principles

6、 of Operation . 5 Chapter 4 MAINTENANCE.8 4.1Customer Service. 8 4.2 Instrument Return. 8 Figures Figure 1.1 1433 Series High Accuracy Decade Resistor . 1 Figure 3.1 A simplified equivalent circuit for a decade box with the low (L) terminal tied to case . 5 Figure 3.2 Equivalent three terminal circu

7、it for a decade box with neither terminal tied to case . 6 Figure 3.3 Approximation of distributed capacitance effects . 7 vii WARNING OBSERVE ALL SAFETY RULES WHEN WORKING WITH HIGH VOLTAGES OR LINE VOLTAGES. Dangerous voltages may be present inside this instrument. Do not open the case Refer servi

8、cing to qulified personnel HIGH VOLTAGES MAY BE PRESENT AT THE TERMINALS OF THIS INSTRUMENT WHENEVER HAZARDOUS VOLTAGES ( 45 V) ARE USED, TAKE ALL MEASURES TO AVOID ACCIDENTAL CONTACT WITH ANY LIVE COMPONENTS. USE MAXIMUM INSULATION AND MINIMIZE THE USE OF BARE CONDUCTORS WHEN USING THIS INSTRUMENT.

9、 Use extreme caution when working with bare conductors or bus bars. WHEN WORKING WITH HIGH VOLTAGES, POST WARNING SIGNS AND KEEP UNREQUIRED PERSONNEL SAFELY AWAY. CAUTION DO NOT APPLY ANY VOLTAGES OR CURRENTS TO THE TERMINALS OF THIS INSTRUMENT IN EXCESS OF THE MAXIMUM LIMITS INDICATED ON THE FRONT

10、PANEL OR THE OPERATING GUIDE LABEL. 1 INTRODUCTION 1433 Series Chapter 1 INTRODUCTION other conductors within the instrument, as well as the solder employed, contain no metals or junctions that contribute to thermal emf problems. With a resolution as low as 1 m and a maximum available resistance of

11、over 111 M, the 1433 series may be used for exacting precision measurement ap- plications requiring high accuracy, good stability, and low zero-resistance. They can be used as compo- nents of dc and ac bridges, for calibration, as transfer standards, and as RTD simulators. The 1433 Series may be rac

12、k-mounted to serve as components in measurement and control systems. This series is part of a family of resistance substitut- ers suited to fill many engineering and testing needs. Consult IET for: High-power substituters - up to 400 W High-resistance substituters - to 1 T RTD simulators Laboratory-

13、standard-grade substituters - to 1 ppm accuracy Programmable substituters - IEEE-488 or BCD. 1.1 Product Overview The 1433 Decade Resistors are a family of instru- ments providing a very broad choice of high-perfor- mance resistance sources. Any number of decades from one to eleven is available. The

14、 1433 is a precision resistance source with ex- cellent characteristics of stability, temperature coef- ficient, power coefficient, and frequency response. There are over 30 models available covering a wide resistance range from 1 m to over 111 M. The 1433 Series employs stable very low resistance s

15、witches with silver alloy contacts. A special design keeps zero-resistance to less than 1 m per decade. Self-cleaning keeps the silver contacts from becom- ing tarnished when unused, or when only low cur- rents are passed through them. This is most often the case when only minute test currents are d

16、rawn by digital multimeters or other test instruments. Contact resistance is stable and remains low and repeatable. The dials, labeled 0 to X(=10), offer smooth rotation from position to position with no stops. Each dial has the overlap X(10) position for maximum convenience and flexibility in setti

17、ng and adjusting resistance val- ues. The resistance per step and maximum current of each dial are clearly shown on the front panel. Elec- trical shielding is provided by an attractive aluminum cabinet and front panel. The resistance elements have no electrical connection to the cabinet and panel; a

18、 separate shield terminal is provided. High-quality gold-plated tellurium-copper binding posts serve to minimize the thermal emf effects which can introduce errors into dc resistance measurements. All Figure 1.1. 1433 Series High Accuracy Decade Resistor 2 INTRODUCTION 1433 Series 1.2 Accessories In

19、cluded Table 1-3 ItemQuantity Instruction Manual1 Calibration Certificate1 1.3 Accessories/Options Available Table 1-4 ItemPart Number Rack Mount Kit for 4 dial units1433-50 Rack Mount Kit for 5 dial units1433-51 Rack Mount Kit for 6 dial units1433-52 Rack Mount Kit for 7 dial units1433-53 3 SPECIFI

20、CATIONS 1433 Series R/stepTotal RAccuracy ofStabilityL/stepMaxPowerTempco () ()R Increments ppm/yr(H)Input/step (W)ppm/oC 0.0010.014%500-5 A0.02550 0.010.12%5000.014 A0.1620 0.110.4%500.11.6 A0.2520 1100.1%200.15800 mA0.620 101000.04%200.55250 mA0.615 10010000.01%20580 mA0.6 5 1,00010,0000.01%201523

21、 mA0.5 5 10,000100,0000.01%20757 mA0.5 5 100,0001,000,0000.01%20-2.3 mA0.5 5 1,000,00010,000,0000.01%20-0.7 mA0.510 10,000,000100,000,0000.01%20-0.23 mA0.110 Typical Frequency Characteristics: Chapter 2 SPECIFICATIONS Range: 1 m to 111.111.111.110 in 1 m steps. Overall Accuracy: The difference betwe

22、en the resistance at any setting and at the Zero setting is equal to the indi- cated value (0.01% + 2 m) Decade Specifications 4 SPECIFICATIONS 1433 Series Typical Value of Zero Impedance: Zero Resistance (Ro): 0.001 /decade at dc; 0.04 /decade at 1 MHz; proportional to square root of fre- quency ab

23、ove 100 kHz. Zero Inductance (Lo): 0. 1 H/decade + 0.2 H. Effective Shunt Capacitance (C): Value is determined largely by the highest decade in use. With the low terminal con- nected to the shield, a value of 15 to 20 pF/ decade may be assumed, counting decades down from the highest. Thus, if the th

24、ird de- cade from the top is the highest resistance, a value of 45 to 60 pF may be assumed. If the highest decade in the unit is in use, the effec- tive capacitance is 15 to 20 pF, regardless of the settings of the lower-resistance decades. Switches: Continuous rotation; solid silver-alloy contacts;

25、 contact resistance of less than 1 m; capacitance of less than 1 pF between contacts; lifetime in excess of 1 million cycles. Maximum voltage to case: 2000 V peak Terminals: Gold plated, tellurium-copper, low-thermal-emf binding posts on standard 3/4 inch spacing; shield terminal provided. Mechanica

26、l: Dimensions: in inches (mm) Weight: in lb (kg) LWDWt 4 dial 12.3 (312)3.5 (89)5.0 (127)3.5 (1.6) 5 dial 14.8 (375)3.5 (89)5.0 (127)4.0 (1.8) 6 dial 17.3 (439)3.5 (89)5.0 (127)4.5 (2.0) 7 dial 17.3 (439)5.3 (135) 5.0 (127)6.0 (2.7) Environmental: Operating:+10 to +40oC, 80% RH Storage:-20 to +65oC

27、Supplied with unit: Instruction manual Calibration Certificate Accessories available: 1433-50 Rack Mount Kit for 4-dial units 1433-51 Rack Mount Kit for 5-dial units 1433-52 Rack Mount Kit for 6-dial units 1433-53 Rack Mount Kit for 7-dial units Ordering Information: CatalogTotalOhmsNo. No.()/stepof

28、 dials 1433-011.110.0013 1433-00111.10.014 1433-021,1110.14 1433-0411,11014 1433-06111,100104 1433-081,111,0001004 1433-0911,110,00010004 1433-09A 111,100,00010,0004 1433-101,111.10.015 1433-1211,1110.15 1433-14111,11015 1433-161,111,100105 1433-1811,111,0001005 1433-18A 111,110,00010005 1433-191,11

29、1.110.0016 1433-2011,111.10.016 1433-22111,1110.16 1433-241,111,11016 1433-2611,111,100106 1433-27111,111,0001006 1433-2811,111.110.0017 1433-29111,111.10.017 1433-311,111,1110.17 1433-3311,111,11017 1433-34111,111,100107 1433-35111,111,11018 1433-361,111,111,100108 1433-3711,111,111,0001008 1433-38

30、111,111,110,00010008 1433-391,111,111.110.0019 1433-39A 11,111,111.10.019 1433-39B 111,111,1110.19 1433-40A 11,111,111,1100.00110 1433-40111,111,111.10.0110 1433-41111,111,111.110.00111 5 OPERATION 1433 Series Chapter 3 OPERATION 3.1 Installation All models of the 1433 Decade Resistor are sup- plied

31、 as bench instruments but may be rack mounted. Installation in a standard 19-inch rack requires a Rack Mount Kit whose part number depends on the num- ber of dials on the unit. Refer to paragraph 1.3 3.2 Connections The terminals on the front panel of the 1433 are stan- dard 3/4-inch-spaced binding

32、posts that accept ba- nana plugs, phone plugs, spade lugs, various clips, and wire sizes up to No. 12. The high (H) and low (L) binding posts are insulated from the panel and used for regular two-terminal applications. For grounded operation, connect the shorting link between the ground (G) terminal

33、 and the low (L) terminal. Refer to para- graph 3.4 for a detailed comparison of two- and three- terminal connections. If switches have not been operated for an extended period, they should be rotated a few times to restore contact resistance to specifications. 3.3 Dial Readout All 1433 decades have

34、 easy-to-read dials with num- bered steps from 0 to X (= 10). When setting the decade switches, observe the decimal point on the panel and remember that X equals ten units. For ex- ample, the five dial Model 1433-10 is set for a value of 54.3 by setting the decade switches as follows: 0 5 4 . 3 0 =

35、54.3 or 0 5 4 . 2 X = 54.3 Note that X, in the above example, is equal to a value of ten 0.01 W units in that decade, or one 0.1 unit in the next decade to the left. The following examples illustrates the result of set- ting all decades in the 1433-10 to X. Dial setting: X X X . X X Resistance value

36、:1 1 1 1 . 1 0 3.4 Principles of Operation The best approximation of a complete equivalent circuit for a 1433 Decade Resistor is shown in Figure 3-1. Figure 3-1. A simplified equivalent circuit for a decade box with the low (L) terminal tied to case In Figure 3-1: R = setting of the decade box. L =L

37、O= N1 L1 + N2 L2 + . where Lo 0.1 H per decade x number of decades in unit + 0.2 H. L1, L2,. L/step values from specifications. N1, N2,. settings of corresponding decades. C=Co+MC1 where CO 15 pF C1 20 pF M = number of unused decades (set to zero) preceding first decade used. 6 OPERATION 1433 Series

38、 The phase angle (Q) for this circuit is: Q(L/R - RC). At low values of R, the L/R term is dominant; at high values of R, the RC term is more important. The effective series resistance is: The effective parallel resistance is: At low values, the series resistance remains constant to rather high freq

39、uencies because inductance has no effect on Rs. At very low values, skin effect increases Rs. At high values, the series resistance falls off rather rapidly with frequency because of capacitance. The parallel resistance, however, is not affected by the lumped capacitance shown in the simple equivale

40、nt circuit (see Figure 3-1). The parallel value is affected by distributed capacitance and dielectric loss not shown. An approximate equation that considers these effects on Rp is: The R10-13 term represents dielectric loss, the next term represents distributed capacitance in the first decade used (

41、not zero), and the last term represents distributed capacitance in the first decade if it is not used (set to zero), where Ry is the total possible value of that decade. (The last term is not used if the first decade is not set to zero). When the case is not tied to either terminal, the decade resis

42、tor becomes a three-terminal circuit as shown in Figure 3-3. Rs = R 1+2R2C2 Rp = R(1+ 2 L2 R2 ) Rp R1+ - R10-3- 42R210-24-252RRy10-24 2 L2 R2 Figure 3-2. Equivalent three terminal circuit for a decade box with neither terminal tied to case In Figure 3-2: R = setting of the decade box. L = LO = N1 L1

43、 + N2 L2+ . where Lo 0.1 H per decade x number of de- cades in unit + 0.2 H. L1, L2, . L/step values from specifica- tions. N1, N2, . settings of corresponding decades. Ca = l0 Ma + 8 pF where Ma = number of unused decades (set to zero) preceding first decade used. Cb = 20 Mb + 20 pF where Mb = numb

44、er of unused decades (set to zero) preceding first decade used. Cs = 2 pF 7 OPERATION 1433 Series There is also some distributed capacitance (Cd) from the resistor to the case, as shown in Figure 3-3. This capacitance has the effect of increasing the effec- tive inductance by an amount of approximat

45、ely N3R2C x 10-3: where N is the setting of the first used (not zero) decade, R is the total value of the decade resistor, and C is 2 pF. Figure 3-3. Approximation of distributed capacitance effects 8 MAINTENANCE 1433 Series Chapter 4 MAINTENANCE 4.2 Instrument Return Before returning an instrument to IET for service please call our Service Department at