Given the limitations of the two-wire method, the four-wire (Kelvin) method is generally preferred for low-resistance measurements. These measurements can be made using a separate current source and voltmeter (Figure 2).
With this configuration, the test current is forced through the test resistance via one set of test leads (power leads), while the voltage across the component under test is measured through a second set of leads (sense leads). Although some small current may flow through the sense pair, it is usually negligible (pA or less) because the impedance of the sense terminals is high. The volt drop measured by the meter is therefore essentially the same as the voltage across the test resistance. Consequently, the resistance value can be determined much more accurately than with the two-wire method.