Low Resistance Measurement Methods

The four wire kelvin method of measurement is preferred for resistance values below 100 ω and all cropico milliohmmeters and microhmmeters use this method.

Low resistance measurement methods.

This is the most crude and simplest method of measuring resistance. In the above picture r is the unknown resistor and v is a multimeter set to read millivolts. Carey foster bridge method 3 measurement of high resistance. 1 measurement of low resistance.

The dc potentiometer method of measurement of resistance is used for measuring the unknown resistance of low value. Some basic methods are suitable for low as well as medium resistances. Low resistance measurement method basically the trick is to pass a stable known amount of current through the low value resistor and measure the voltage drop across it. Obviously the multimeter is connected permanently as shown in picture.

These measurements are made using 4 separate wires. 2 wires carry the current known as the source or current leads and pass current through the rx. 2 wires carry the current known as the source or current leads and pass current through the rx. These measurements are made using 4 separate wires.

Ohm meter method 2 measurement of medium resistance. This can be done by comparing the unknown resistance with the standard resistance. The methods are listed below. Carey foster bridge method.

A low resistance measurement is typically a measurement below 1 000 ohm. Also at this level standing. The voltage drop across the known and unknown resistance is measured and by comparison the value of known resistance is determined. At this level it is important to use test equipment that will minimize errors introduced by the test lead resistance and or contact resistance between the probe and the material being tested.

Kelvin double bridge method. Special connecting clips called kelvin clips are made to facilitate this kind of connection across a subject resistance. Kelvin method this method of measurement which avoids errors caused by wire resistance is called the kelvin or 4 wire method.