Ohm Labs 100-0 Zero Ohm standard

The Ohm Labs 100-0 Zero Ohm standard is a four-wire Zero Ohm reference for monitoring long scale multimeters, micro-ohmmeters, or other equipment that monitors a true short circuit.

Zero Ohm, in any connection configuration, is provided by means of a tetrajunction. A tetra function is an ideal four wire connection, so that when you send current through any two connections, there is no potential difference over the other two connections.

Based on the work of, for example, Hamon and others at the NIST, a ‘copper disk’ and connection construction has been evaluated and then commercialized in Leeds & Northrup’s Hamon transfer standards.

Verification of the 100-0 standard can be performed by passing current through different pairs of the terminals and viewing the voltage across the remaining pair. The 100-0 is factory set at less than 50 Nano-ohm in each connection configuration. The tetraj function does not drift measurably over time.


Resistance < 50 nano-ohms
Current Up to 5 amps continuous
Size 90x64x60 (3.5×2.5×2.25 in)
Weight 300 g (1.2 lbs)
Environmental 20-40 °C, 10-90 %RH
Storage -40+65 °C, 0-95 %RH


For more information about electrical standards, please refer to the overview page or contact one of our consultants.

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