The Columbia Encyclopedia, Sixth Edition. 2001-07.
ammeter
(m´m´´tr) (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 dArsonval 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.