Wednesday, January 11, 2017
Galvanometer
is the historical name given to a moving coil electric current detector. When a
current is passed through a coil in a magnetic field, the coil experiences a
torque proportional to the current. If the coil's movement is opposed by a coil
spring, then the amount of deflection of a needle attached to the coil may be
proportional to the current passing through the coil. Such "meter
movements" were at the heart of the moving coil meters such as voltmeters
and ammeters until they were largely replaced with solid state meters.
The accuracy
of moving coil meters is dependent upon having a uniform and constant magnetic
field. The illustration shows one configuration of permanent magnet which was
widely used in such meters.
