μΩ

microohm

Resistanceexact by definition

The microohm is one millionth of an ohm. It is the unit of low-resistance ohmmeter work: circuit breaker and switchgear contact resistance, bolted busbar joints, weld and crimp quality, and the shunts used to measure large currents are all specified in microohms. The factor of 1e-6 is exact, being an SI prefix.

Watch out: A microohm reading is only meaningful with a stated test current and a stated temperature. A joint that measures well at 10 A can behave differently at 1000 A, which is why acceptance tests specify a current comparable to service.

1 μΩ 0.000001 Ω