Fig. 31. Methods for measuring resistance.
Let Ra = resistance of the ammeter (which is very small),
Rv = resistance of the voltmeter (which is a large value),
R = resistance to be measured,
V = reading of the voltmeter, and
I = reading of the ammeter.
Fig. 31 (a) shows the connections for measurement of low resistances.
Fig. 31 (b) shows the connections for measurement of high and low resistances.
Here V = IRa + IR