Kerry Wong shows us a project that allows for accurate Milliohm Measurement. For day to day applications your trusty hand held multimeter will probably do just fine, but when you need to make a very accurate low resistance reading this circuit is sure to help you out.
“I used the reference design for the unity-gain difference amplifier AD8276 and a precision Op-Amp AD8603 from Analog Devices to form the precision constant current source. An AS431 precision shunt voltage reference is used for the 2.5V reference voltage. Using this design, the constant load current is Vref/R2. R2 (250 Ohm) will need to have relatively high precision in order for the load current to be accurate. If you are using other precision voltage references, the value of R2 will need to be adjusted so that Vref/R2=10 mA.”