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 < 4 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

Features:
• 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)
• Very low zero-resistance: <1 mΩ per decade
• High-performance solid silver-alloy switches
• Low temperature coefficient: 5 ppm/°C