Abstract: A saturable reactor device for limiting alternating and direct current in an external electric circuit. In one form, the required magneto-motive force (mmf) bias for the saturable reactor is provided by a controllable flux bias element in order to minimize the required bias power. A current sensor provides a control signal representative of the alternating or direct current passing between the source and the load. This signal is used to control the magnitude of the bias so that the mmf provided by the bias element is a function of the current driving the load, permitting a current limiting threshold at a predetermined percentage of the current applied to the load. In an alternate form, the device may be adapted to limit bipolar current in the external circuit. In this form, the device includes an input circuit and an associated direct current saturable reactor limiter.