[′pər·mə·nənt ¦mag·nət ¦müv·iŋ ¦kōil ′in·strə·mənt] (engineering) An ammeter or other electrical instrument in which a small coil of wire, supported on jeweled bearings between the poles of a permanent magnet, rotates when current is carried to it through spiral springs which also exert a restoring torque on the coil; the position of the coil is indicated by an attached pointer.