Ohm meter method 2 measurement of medium resistance.
Low resistance measurement methods.
This is the most crude and simplest method of measuring resistance.
Carey foster bridge method.
The four wire kelvin method of measurement is preferred for resistance values below 100 ω and all cropico milliohmmeters and microhmmeters use this method.
The voltage drop across the known and unknown resistance is measured and by comparison the value of known resistance is determined.
Carey foster bridge method 3 measurement of high resistance.
Kelvin method this method of measurement which avoids errors caused by wire resistance is called the kelvin or 4 wire method.
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.
Following are the methods employed for measuring a resistance whose value is in the range 1ω 100kω ammeter voltmeter method.
Special connecting clips called kelvin clips are made to facilitate this kind of connection across a subject resistance.
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.
The methods are listed below.
What is a low resistance measurement.
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.
2 wires carry the current known as the source or current leads and pass current through the rx.
Some basic methods are suitable for low as well as medium resistances.
These measurements are made using 4 separate wires.
1 measurement of low resistance.
A low resistance measurement is typically a measurement below 1 000 ohm.
In the above picture r is the unknown resistor and v is a multimeter set to read millivolts.
Kelvin double bridge method.
Also at this level standing.
