Inne IET 1433 User Manual

♦ PRECISION INSTRUMENTS FOR TEST AND MEASUREMENT ♦

1433 SERIES

High-Accuracy

Decade Resistor

User and Service Manual

1433 im/December, 2003

IET LABS, INC.

formerly manufacturer by

GenRad

Copyright © 2003 IET Labs, Inc.

534 Main Street, Westbury, NY 11590
TEL: [phone] • [phone] • FAX: [phone]

www.ietlabs.com

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 this 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 indirect, 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, INCLUD­ING BUT NOT LIMITED TO, ANY IMPLIED WARRANTY OF MERCHANTIBILITY OR FITNESS FOR
ANY PARTICULAR PURPOSE.

iii

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 of Operation .......................................................... 5

Chapter 4

MAINTENANCE............................................................................ 8

4.1 Customer 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 circuit for a decade box with neither

terminal tied to case ............................................................... 6

Figure 3.3 Approximation of distributed capacitance effects .................. 7

ii

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 servicing 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.

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 PANEL OR THE OPERATING GUIDE LABEL.

vii

Chapter 1

INTRODUCTION

1433 Series

1.1 Product Overview

The 1433 Decade Resistors are a family of instru­ments providing a very broad choice of high-perfor­mance resistance sources. Any number of decades
from one to eleven is available.

The 1433 is a precision resistance source with ex­cellent characteristics of stability, temperature coef­ficient, power coefficient, and frequency response.

There are over 30 models available covering a wide
resistance range from 1 mΩ to over 111 MΩ. The
1433 Series employs stable very low resistance
switches with silver alloy contacts. A special design
keeps zero-resistance to less than 1 mΩ per decade.
Self-cleaning keeps the silver contacts from becom­ing tarnished when unused, or when only low cur­rents are passed through them. This is most often the
case when only minute test currents are drawn 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 setting and adjusting resistance val­ues. The resistance per step and maximum current of
each dial are clearly shown on the front panel. Elec­trical shielding is provided by an attractive aluminum
cabinet and front panel. The resistance elements have
no electrical connection to the cabinet and panel; a
separate shield terminal is provided.

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 mΩ and a maximum
available resistance of over 111 MΩ, the 1433 series
may be used for exacting precision measurement ap­plications requiring high accuracy, good stability, and
low zero-resistance. They can be used as compo­nents of dc and ac bridges, for calibration, as transfer
standards, and as RTD simulators.

The 1433 Series may be rack-mounted to serve as
components in measurement and control systems.

This series is part of a family of resistance substitut­ers suited to fill many engineering and testing needs.
Consult IET for:

High-power substituters - up to 400 W
High-resistance substituters - to 1 TΩ
RTD simulators
Laboratory-standard-grade substituters - to 1 ppm

accuracy

Programmable substituters - IEEE-488 or BCD.

High-quality gold-plated tellurium-copper binding posts
serve to minimize the thermal emf effects which can
introduce errors into dc resistance measurements. All

INTRODUCTION

Figure 1.1. 1433 Series High Accuracy Decade
Resistor

1

1433 Series

1.2 Accessories Included

Table 1-3

Item Quantity

Instruction Manual 1
Calibration Certificate 1

1.3 Accessories/Options Av ailable

Table 1-4

Item Part Number

Rack Mount Kit for 4 dial units 1433-50
Rack Mount Kit for 5 dial units 1433-51
Rack Mount Kit for 6 dial units 1433-52
Rack Mount Kit for 7 dial units 1433-53

2

INTRODUCTION

SPECIFICATIONS

Range:

1 mΩ to 111.111.111.110 Ω in 1 mΩ steps.

Overall Accuracy:

The difference between the resistance at any
setting and at the Zero setting is equal to the indi­cated value ± (0.01% + 2 mΩ)

Decade Specifications

1433 Series

Chapter 2

R/step Total R Accuracy of Stability L/step Max Power Tempco
(Ω) (Ω) R Increments ppm/yr (µH) Input /step (W) ppm/

0.001 0.01 ±4% 500 - 5 A 0.025 50

0.01 0.1 ±2% 500 0.01 4 A 0.16 20

0.1 1 ±0.4% 50 0.1 1.6 A 0.25 20
1 10 ±0.1% 20 0.15 800 mA 0.6 20
10 100 ±0.04% 20 0.55 250 mA 0.6 15
100 1000 ±0.01% 20 5 80 mA 0.6 5
1,000 10,000 ±0.01% 20 15 23 mA 0.5 5
10,000 100,000 ±0.01% 20 75 7 mA 0.5 5
100,000 1,000,000 ±0.01% 20 - 2.3 mA 0.5 5
1,000,000 10,000,000 ±0.01% 20 - 0.7 mA 0.5 10
10,000,000 100,000,000 ±0.01% 20 - 0.23 mA 0.1 10

Typical Frequency
Characteristics:

o

C

SPECIFICA TIONS

3

1433 Series

Typical Value of Zero Impedance:

Zero Resistance (Ro):

0.001 Ω/decade at dc; 0.04 Ω/decade at
1 MHz; proportional to square root of fre­quency above 100 kHz.

Zero Inductance (Lo):

0. 1 µH/decade + 0.2 µH.

Effective Shunt Capacitance (C):

Value is determined largely by the highest
decade in use. With the low terminal con­nected to the shield, a value of 15 to 20 pF/
decade may be assumed, counting decades
down from the highest. Thus, if the third de­cade 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 effec­tive capacitance is 15 to 20 pF, regardless of
the settings of the lower-resistance decades.

Switches:

Continuous rotation; solid silver-alloy contacts;
contact resistance of less than 1 mΩ; 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.

Mechanical:

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:

o

Operating: +10 to +40
Storage: -20 to +65

C, <80% RH

o

C

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:

Catalog Total Ohms No.
No. (Ω) /step of dials
1433-01 1.11 0.001 3
1433-00 111.1 0.01 4
1433-02 1,111 0.1 4

1433-04 11,110 1 4
1433-06 111,100 10 4
1433-08 1,111,000 100 4
1433-09 11,110,000 1000 4
1433-09A 111,100,000 10,000 4
1433-10 1,111.1 0.01 5
1433-12 11,111 0.1 5
1433-14 111,110 1 5
1433-16 1,111,100 10 5
1433-18 11,111,000 100 5
1433-18A 111,110,000 1000 5
1433-19 1,111.11 0.001 6
1433-20 11,111.1 0.01 6
1433-22 111,111 0.1 6
1433-24 1,111,110 1 6
1433-26 11,111,100 10 6
1433-27 111,111,000 100 6
1433-28 11,111.11 0.001 7
1433-29 111,111.1 0.01 7
1433-31 1,111,111 0.1 7
1433-33 11,111,110 1 7
1433-34 111,111,100 10 7
1433-35 111,111,110 1 8
1433-36 1,111,111,100 10 8
1433-37 11,111,111,000 100 8
1433-38 111,111,110,000 1000 8
1433-39 1,111,111.11 0.001 9
1433-39A 11,111,111.1 0.01 9
1433-39B 111,111,111 0.1 9
1433-40A 11,111,111,110 0.001 10
1433-40 111,111,111.1 0.01 10
1433-41 111,111,111.11 0.001 11

4

SPECIFICATIONS

Chapter 3

OPERATION

1433 Series

3.1 Installation

All models of the 1433 Decade Resistor are sup­plied 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 num­ber of dials on the unit. Refer to paragraph 1.3

3.2 Connections

The terminals on the front panel of the 1433 are stan­dard 3/4-inch-spaced binding posts that accept ba­nana 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 and the low (L) terminal. Refer to para­graph 3.4 for a detailed comparison of two- and three­terminal 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 easy-to-read dials with num­bered 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 ex­ample, the five dial Model 1433-10 is set for a value
of 54.3 Ω by setting the decade switches as follows:

0 5 4 . 3 0 = 54.3 Ω

or

0 5 4 . 2 X = 54.3 Ω

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 Ω unit
in the next decade to the left.

The following examples illustrates the result of set­ting all decades in the 1433-10 to X.
Dial setting: X X X . X X
Resistance value: 1 1 1 1 . 1 0 Ω

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.

= N

∆ L

+ N

∆ L

L =L

O

1

1

where Lo ≈ 0.1 µH per decade x number of decades
in unit + 0.2 µH.

, ∆ L2,....... ≈ L/step values from specifications.

∆ L

1

, N

,... ≈ settings of corresponding decades.

N

1

2

C=Co+MC
where C

1

≈ 15 pF

O

≈ 20 pF

C

1

M = number of unused decades (set to zero)
preceding first decade used.

+ ....

2

2

OPERATION

5

1433 Series

The phase angle (Q) for this circuit is:

Q≈ω(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:

1+ω

R

2R2C2

Rs =

The effective parallel resistance is:

2 L2

Rp = R(1+

ω

)

2

R

At low values, the series resistance remains constant to
rather high frequencies 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 equivalent
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:

2 L2

Rp ≈ R[1+ - ωR10-3- 4ω

The ωR10

ω

2

R

-13

term represents dielectric loss, the next

2R210-24

-25ω

2

RRy10

-24

term represents distributed capacitance in the first
decade used (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 resistor becomes a
three-terminal circuit as shown in Figure 3-3.

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 = L

O

= N

1 ∆L1

+ N

2 ∆L2

+ ....

where Lo ≈ 0.1 µH per decade x number of de­cades in unit + 0.2 µH.

, ∆ L2, ... ≈ L/step values from specifica-

∆ L

1

tions.

, N

, ... ≈ settings of corresponding decades.

N

1

2

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 = number of unused decades (set to zero)

]

preceding first decade used.

Cs = 2 pF

6

OPERATION

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 effec­tive inductance by an amount of approximately

3R2

C x 10-3: where N is the setting of the first used

N
(not zero) decade, R is the total value of the decade
resistor, and C is 2 pF.

1433 Series

Figure 3-3. Approximation of distributed
capacitance effects

OPERATION

7

1433 Series

Chapter 4

MAINTENANCE

4.1 Customer Service

The IET warranty attests to the quality of materials
and workmanship in our products. For application
assistance or if difficulties occur, our engineers will
assist in any way possible. If you cannot eliminate
the difficulty, please e-mail, FAX, or phone our Ser­vice Department, giving full information of the trouble
and of steps taken to remedy it. Be sure to include
the type and serial number of the instrument.

In the U. S. call
617-969-0804 for technical support
800-899-8438 or 516-334-5959 for customer service
516-334-5988 for FAX

www.ietlabs.com

4.2 Instrument Return

Before returning an instrument to IET for service
please call our Service Department at 800-899-8438
for Return Material Authorization (RMA). Include a
Purchase Order Number to insure expedient process­ing. Units under warranty will be repaired at no
charge. For any questions on repair costs or ship­ment instructions, please contact our Service De­partment at the above number. To safeguard an in­strument during shipment, please use packaging that
is adequate to protect it from damage, (i.e., equiva­lent to the original packaging) and mark the box “Deli­cate Electronic Instrument”. Return material should
be sent freight prepaid to:

IET Labs, Inc.
10 Dedham Street
Newton, MA 02461

Attention: Service Department

8

MAINTENANCE