A Magnetic Curve Tracer

Abstract

An apparatus for photographically recording hysteresis loops and initial magnetization curves is described. It employs a rotating drum and a fluxmeter, the restoring torque of the latter being completely counter-balanced by a photoelectric cell arrangement. With this apparatus curves may be taken so slowly that eddy currents are negligible. The accuracy of the instrument is intrinsically as great as that of a ballistic galvanometer. An analysis of sources of error is included.