A method for changing the inductance of a multiple-tap transformer in a circuit having a current regulator and the transformer, including the steps of comparing the current regulator's duty-cycle to a duty-cycle setpoint, increasing the turns ratio of the transformer when the duty-cycle is less than the setpoint. An apparatus for switching the taps of a multiple-tap transformer connected to a power supply and a load circuit, including a load regulator for generating a desired duty-cycle signal, and an inductance controller having a first reference signal generator, a comparator for comparing the reference signal to the desired duty-cycle, and relays connected to the transformer taps that are responsive to the comparator.