HARS Series Resistance Decade Box

Resistance Decade Box

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Photo represents example of series. See datasheet for more details on any specific model.

  • Resistance from 1 mΩ; to 111 MΩ!
  • Available in double-power version: HARS-X2
  • Wide choice: single through 11 decade units
  • High accuracy - 0.01% (100 ppm) or 0.1% depending on model;
  • Very low zero-resistance: <1 mΩ per decade for HARS-X
  • High-performance solid silver-alloy contacts
  • Low temperature coefficient: - 5 ppm/°C
  • Non-inductive or low-inductance resistors
  • Rack mounting available

Prices range from $411 to $6597

Estimated Delivery is 2 to 4 weeks

Repair/Calibration Quote Technical Support Request

The HARS Series is the best choice when you need a laboratory grade, tight tolerance, high performance resistance decade box that is also cost effective.

The High-Accuracy Resistance Substituter (HARS) resistance decade box is a family of instruments providing a very broad choice of high performance resistance sources. The HARS series resistance decade boxes may be used for exacting precision measurement applications requiring high accuracy to 0.01% , good stability typically less than 20 ppm/year, excellent AC frequency response and low zero-resistance.

Any number of decades from one to eleven is available with a resolution as low as 1 mΩ and a maximum available resistance of over 111 MΩ,.

The HARS Series employs very-low-resistance switches < 1 mΩ with silver plated contacts. A special design keeps zero resistance to less than 1 mΩ per decade for the HARS-X. 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 HARS resistance decade boxes have high-quality gold-plated tellurium-copper binding posts that serve to minimize the thermal emf effects which would artificially reflect a change in dc resistance measurements. All other conductors within the resistance decade box, as well as the solder employed, contain no metals or junctions that could contribute to thermal emf problems.

The HARS-X2 is a higher power version of the HARS-X precision resistance decade box with excellent characteristics of stability, temperature coefficient, power coefficient and rated power up to 1.2 watts.

HARS Resistance Decade Box Applications

  • Can be used as components of dc and ac bridges
  • Excellent choice as a resistance calibration or transfer standard
  • As a precision RTD simulator.
  • The HARS Series decade box may be rack-mounted to serve as components in measurement and control systems
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HARS Series Resistance Decade Box

HARS-X Series Resistance Decade Box Basic Specifications

(Full specifications can be found on datasheet)

Accuracy: ≤1 MΩ steps: ±(0.01% + 2 mΩ) 10 MΩ steps: ±0.03% after subtraction of zero resistance, at 23°C; traceable to SI
Zero Resistance: <1 mΩ per decade at dc for ≤1 MΩ decades: 10 MΩ decade: ≈3 mΩ at dc
Maximum Voltage to Case: 2000 V peak Switches:
Continuous rotation 11 positions marked "0"-"10" Multiple solid silver-alloy contacts

HARS-B Series Resistance Decade Box Basic Specifications

Accuracy: (0.1% + 4 mΩ)
Zero Resistance: <5 mΩ per decade at dc
Maximum Voltage to Case: 1000 V peak Switches:
Continuous rotation 10 positions marked "0"-"9" Multiple solid silver-alloy contacts
Resistors: Combination of wirewound, metal film and resistance wire.

Resistance per step
Total decade resistance
Stability (±ppm/yr)
Long-term stability (±ppm/3 yrs)
Temperature coefficient (±ppm/°C)
Resistor type
HARS-X
HARS-X2
Max current
Max voltage  (per step)
Max power (per step)
Max current
Max voltage  (per step)
Max power  (per step)
1 mΩ
10 mΩ
50
75
50
Resistance wire
8 A
5 mV
0.04 W
9:A
9 mV
0.08 W
10 mΩ
100 mΩ
50
75
20
4 A
40 mV
0.16 W
6.3 A
63 mV
0.4 W
100 mΩ
1 Ω
50
75
20
1.6 A
0.16 V
0.25 W
2.2 A
0.3 V
0.5 W
1 Ω
10 Ω
20
25
20
Wirewound, non-inductive
0.8 A
0.8 V
0.6 W
1.1 A
1.1 V
1.2 W
10 Ω
100 Ω
20
25
15
0.25 A
2.5 V
0.6 W
0.35 A
3.5 V
1.2 W
100 Ω
1 kΩ
20
25
5
80 mA
8 V
0.6 W
110 mA
11 V
1.2 W
1 kΩ
10 kΩ
20
25
5
23 mA
23 V
0.5 W
35 mA
35 V
1.2 W
10 kΩ
100 kΩ
20
25
5
7 mA
70 V
0.5 W
11 mA
110 V
1.2 W
100 kΩ
1 MΩ
20
25
5
2.3 mA*
230 V*
0.5 W*
3 mA*
500 V*
1 W*
1 MΩ
10 MΩ
20
25
5
0.7 mA*
700 V*
0.5 W*
1 mA*
1000 V*
1 W*
10 MΩ
100 MΩ
50
100
10
Metal oxide film
0.1 mA*
1000 V*
0.1 W*
0.1 mA*
1000 V*
0.1 W*
*Subject to maximum of 2000 V to case.                

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