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When a current-carrying coil is placed in a magnetic field, it experiences a torque. From the measurement of the deflection of the coil, the strength of the current can be computed. A high resistance is connected in series with the galvanometer to convert it into voltmeter. The value of the resistance is given by:

Here, V= potential difference across the terminal of the voltmeter

= Current through galvanometer

G= Resistance of the galvanometer

When the resistance is connected in series with the galvanometer.

V=I (G+)

When the resistance is connected in series with the galvanometer.

=I (G+)

G=

Let be the resistance required for conversion into voltmeter of range 2V

Also V=