Milliohmeters

A milliohmmeter is a measuring instrument used to measure very low electrical resistances, typically in the milliohm (mΩ) range — values much lower than those measured with a standard ohmmeter. How does a milliohmmeter work? A milliohmmeter injects a stable, high current (generally several amperes or more) into the object whose resistance needs to be measured, using the Kelvin (4‑wire) method. This method avoids the parasitic resistance of the measurement leads by measuring the voltage as close as possible to the sample. By applying Ohm’s law (R = U / I), the device can determine the resistance with very high accuracy — down to the micro‑ohm.