4-Wire Resistance Measurement with a Low Resistance Ohmmeter

Published: Aug 22, 2011 9:00 AM 

AEMC 6250 10A Micro-OhmmeterResistance in an electrical system may be good or bad depending on the purpose. Insulators should have high resistivity to ensure that current will not flow outside the main conductor and cause problems like electric shocks or short circuits. Resistance is a bad thing for conductors because it reduces the efficiency of power delivery. This results in power loss and heat generation which may lead to electrical breakdown.

Measuring resistance in conductors is done using a MicroOhmmeter, also called a digital low resistance Ohmmeter.

This tool measures resistance using a different method compared to the traditional Ohmmeter. It often uses a 4-wire or a Double Kelvin Bridge to measure very low resistance. This measuring method allows it to give accurate because it cancels out the wire and terminal resistance. Using Ohm’s law (R=E/I), we can determine the resistance of the test sample by knowing the current flowing and the voltage drop across the test sample. In a DLRO, this calculation is done automatically by the microprocessor and displayed on the digital read out of the device.

If you need test equipment for measuring low resistance, you might want to consider renting from Protec. Give us a call at 1-866-352-5550 to speak with an equipment expert.

Megger DLRO10HD 10A Digital Low Resistance Ohmmeter

Megger DLRO200-115 200A Digital Low Resistance Ohmmeter

AEMC 6250 10A Micro-Ohmmeter

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