Basic Galvanometer

To convert a galvanometer into a voltmeter, a resistance needs to be connected in series with the galvanometer. The total resistance is given by: where is the desired voltmeter range, and is the full-scale deflection current. Substituting these values: Given that the galvanometer has an internal resistance of , the resistance to be added is:

Step 1: A moving coil galvanometer is a highly sensitive device used to detect small currents.
Step 2: To modify it into an ammeter, which can measure large currents, a shunt resistance ( ) is connected in parallel: where represents the galvanometer's resistance, is the total current, and is the current corresponding to full-scale deflection of the galvanometer. \bigskip