ammeter (ămˈmēˌtər) [key], instrument used to measure the magnitude of an electric current of several amperes or more. An ammeter is usually combined with a voltmeter and an ohmmeter in a multipurpose instrument. Most ammeters are based on the d'Arsonval galvanometer and are of the analog type, i.e., they give current values that can vary over a continuous range as indicated by a scale and pointer or digital readout.
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