An ammeter is an instrument used to measure the current in a circuit. Electric currents are measured in amperes, hence the name. For direct measurement, the ammeter is connected in series with the cir
Demonstration model of a moving iron ammeter. As the current through the coil increases, the plunger is drawn further into the coil and the pointer deflects to the right.
Ammeter from the University of Dundee Physics Department
Ammeter from the old New York Penn Station terminal service plant in New York City
Face of an older moving iron ammeter with its characteristic non-linear scale. The moving iron ammeter symbol is in the lower-left corner of the meter face.
A galvanometer is an electromechanical measuring instrument for electric current. Early galvanometers were uncalibrated, but improved versions, called ammeters, were calibrated and could measure the f
Ammeter
…noted by Hans Christian Ørsted in 1820, who observed a compass needle was deflected from pointing North when a current flowed in an adjacent wire. The tangent galvanometer was used to measure currents using this effect, where the restoring force returning the pointer to the zero position was provided by the Earth's magnetic…
An early D'Arsonval galvanometer showing magnet and rotating coil
Close-up view (rear) of a permanent magnet type moving coil meter
Closed-loop galvanometer-driven laser scanning mirror
A galvanometer mechanism (center part), used in an automatic exposure unit of an 8 mm film camera, together with a photoresistor (seen in the hole on top of the leftpart).