- Low zero-resistance: <5 mΩ per decade for HARS-B
- High-performance solid silver-alloy contacts
- Low temperature coefficient: - 5 ppm/°C
- Non-inductive or low-inductance resistors
- Rack mounting available

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. With a resolution as low as 1 mΩ and a maximum available resistance of over 111 MΩ, the HARS series resistance decade boxes may be used for exacting precision measurement applications requiring high accuracy, good stability, and low zero-resistance. Any number of decades from one to eleven is available in a choice of accuracies.

The HARS resistance decade box is a precision resistance source with excellent characteristics of stability, temperature coefficient, power coefficient, and frequency response. The HARS Series employs very-low-resistance switches with silver alloy 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 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. **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

**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. |