Measuring Low Resistance values below 0.1 OHM


There is a test method called the four-wire (Kelvin sensing) connection method which is a method to help measure a low resistance value.
These measurements can be made using a DMM, micro-ohmmeter, or a separate current source and voltmeter.
In the four wire configuration, the test current (I) is forced through the test resistance (R.) through one set of test leads, while the voltage (VM) across the DUT is measured through a second set of leads called sense leads.
Although a small amount of current may flow through the sense leads, it can be ignored in this circumstance. The voltage drop across the sense leads is negligible, so the voltage measured by the meter (VM) is essentially the same as the voltage (VR) across the resistance (R.). And this allows the resistance value to be measured more accurately than the two-wire method. See below for schematic explanation of this method.