Methods and apparatus for energizing a wound component are described. In one arrangement, a method of energizing a component with an alternating voltage is provided. The component comprises a coil wound on a magnetic core. The method comprises applying a voltage across the coil that has a first waveform during a first time period and a second waveform during a second time period. The second time period is subsequent to the first time period. The second waveform comprises an oscillating function comprising a sequence of identical waveforms. The first waveform is such that if the coil had zero electrical resistance the variation of flux density in the magnetic core with time would change sign at least once during the first waveform.