Abstract: A flyback converter is provided in which at least part of the energy stored in the primary leakage inductance of the transformer is transferred to the output circuit and converted into a dc component of the converter output so that it is dissipated as useful energy in the load. This is achieved by providing first and second tuning capacitors connected across the transformer primary and secondary windings respectively. The first tuning capacitor sets up a ringing on turn off of the primary current, this ringing being visible on the secondary side of the transformer. The second tuning capacitor creates an anti-phase component to the ringing signal. The main ringing signal and the anti-phase component are then mixed in a non-linear device (for example, the rectifier diode of the output circuit) to produce a dc component that can be dissipated in the load.