Galvanometer

A Galvanometer directly measurescurrent (flowelectric charges) throughwire. It issmall pivoting coilwire infield ofpermanent magnet. The coilattached tothin pointer that traversescalibrated scale. A tiny spring pullscoilpointer tozero position. In some meters,magnetic field acts onsmall pieceironperformsame effect asspring.

Whencurrent flows throughcoil,coil generatesmagnetic field. This field actsor againstpermanent magnet. The coil pivots, pushing againstspring,movingpointer. The hand points atscale indicatingelectric current.

Some scales have mirrors next tomarkings. The reflection ofhandmore accurate, because thereless parallax error.

Extremely sensitive equipment once used mirror galvanometers that substitutedmirror forpointer. A beamlight reflected formmirror acted aslong, massless pointer.

Galvanometers have been replaced by analogdigital convertersmost uses. The term "galvanometer" derives fromnameLuigi Galvani.

See also electrometer, electricity, electronics, electric currentelectric charge.