Question

How is a galvanometer converted into a voltmeter?

Hint:

To convert a galvanometer into a voltmeter, connect a large resistance in series with the galvanometer to limit the current and enable it to measure high voltages.

Answer 1

A galvanometer can be converted into a voltmeter by connecting a high resistance \( R_{\text{v}} \) in series with it. This series resistance is chosen such that it allows only a small current to flow through the galvanometer when a high potential difference is applied. The total resistance of the voltmeter is then the sum of the resistance of the galvanometer and the series resistance:
\[ R_{\text{total}} = R_{\text{g}} + R_{\text{v}} \] This modification ensures that the voltmeter can measure high voltages without damaging the galvanometer or causing excessive current flow.
The full-scale deflection of the galvanometer will correspond to the full-scale voltage of the voltmeter, which can be calibrated accordingly.