There are several situations where you may need to measure low resistance values, down to the milliohm range. One example is locating a short circuit on a PCB, but it’s also useful for testing electrical contacts, wires, and winding resistances. The milliohmmeter adapter presented below allows you to do this together with the multimeter you already have.

The Approach

Multimeters are handy devices that measure basic electrical quantities, such as voltage, current, and resistance. (I won’t go into detail here, as you probably have at least one in your lab.) Typically, voltages and currents can be measured with good precision down to millivolts and microamps, but resistance measurements often stop at 1 Ω.

However, there are several situations where you may need to measure lower resistance values, down to the milliohm range. One example is locating a short circuit on a PCB, but it’s also useful for testing electrical contacts, wires, and winding resistances. For this reason, I deci...