moving-iron voltmeter

moving-iron voltmeter

[′müv·iŋ ¦ī·ərn ′vōlt‚mēd·ər]
(engineering)
A voltmeter in which a field coil is connected to the voltage to be measured through a series resistor; current in the coil causes two vanes, one fixed and one attached to the shaft carrying the pointer, to be similarly magnetized; the resulting torque on the shaft is balanced by control springs.