Principle of Wheatstone Bridge
P / Q = R / S
The value of unknown resistance S can found . as we know the value of P , Q and R . It may be remembered that the bridge is most sensitive , when all the four resistances are of the same order .
Meter Bridge
This is the simplest form of Wheatstone bridge and is specially useful for comparing resistance more accurately .
R / S = l1 / ( 100 – l1 )
where l1 is the length of wire from one end where null point is obtained .
Potentiometer
Potentiometer is an ideal device to measure the potential difference between two points . It consists of a long resistance wire AB of uniform cross section in which a steady direct current is set up by means of a battery .
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