Question

Conversion of Galvanometer into Ammeter —

Answer 1

Conversion of Galvanometer into Ammeter —

• A galvanometer can be converted into an ammeter of given range by connecting a suitable low resistance $S$ called shunt in parallel to the given galvanometer, whose value is given by —

$S=\left(\frac{I_g}{I-I_g}\right) G$

where $I_g$ is the current for full scale deflection of galvanometer, $I$ is the current to be measured by the galvanometer and $G$ is the resistance of galvanometer.

• Ammeter is a low resistance instrument and it is always connected in series to the circuit. An ideal ammeter has zero resistance.
• In order to increase the range of an ammeter $n$ times, the value of shunt resistance to be connected in parallel is $S=G /(n-1)$.