Galvanometer

Galvanometer, instrument used for measuring minute electrical currents. The modern instrument consists of a coil of wire delicately suspended by a thin conducting filament between the poles of a permanent magnet. The galvanometer is connected to a circuit, and when an electrical current flows, the coil is deflected at an angle directly proportional to the strength of the current. A small mirror attached to the coil reflects a spot of light onto a scale that indicates the current's strength.

See also: Electric current.