Galvanometer

Definition

A galvanometer is an instrument for detecting and measuring small electric currents by deflection of a needle. It operates on the principle that an electric current passing through a coil produces a magnetic field.

5 Must Know Facts For Your Next Test

1. Galvanometers are often used in analog voltmeters and ammeters to measure voltage and current, respectively.
2. The deflection of the needle in a galvanometer is proportional to the strength of the current passing through it.
3. A galvanometer can be converted into an ammeter by adding a low-resistance shunt parallel to it.
4. To convert a galvanometer into a voltmeter, a high resistance is added in series with it.
5. The sensitivity of a galvanometer is measured by its ability to detect small currents, typically in microamperes.

Review Questions

• What principle does a galvanometer operate on?
• How can you convert a galvanometer into an ammeter?
• What modification is required to use a galvanometer as a voltmeter?

Related terms

Ammeter:

An instrument used to measure electric current in a circuit.

Voltmeter:

An instrument used for measuring electrical potential difference between two points in an electric circuit.

Shunt Resistor: A low-resistance resistor placed parallel to the meter movement in an ammeter to bypass excess current.