Control arrangement

A control arrangement for use in controlling the electrical supply from a power supply unit including a capacitance to an output, the control arrangement comprising first and second magnetically linked inductors arranged in series with one another and defining therebetween a connection by which they are interconnected, third and fourth magnetically linked inductors each being connected to the connection between the first and second inductors, switch means providing switched connections between the third and fourth inductors and ground, and a controller operable to control the operation of the switch means such that closing of a switch of the switch means results in the formation of an LCR circuit, the capacitance of the power supply unit forming the capacitance of the LCR circuit and the first inductor in combination with the third or fourth inductor forming the inductance of the LCR circuit, the magnetic link between the third and fourth inductors allowing an output to be generated from the other of the third and fourth inductors.