A D.C. supply circuit for a television receiver which has a load circuit including at least one controllable semiconductor switch, the supply circuit comprising means for rectifying an alternating mains supply, a smoothing circuit connected between the rectifying means and load circuit and delay means for delaying the application of the full rectified and smoothed voltage to the load circuit when the receiver is initially turned on, wherein the delay means include means for inhibiting a certain number of cycles of the rectified A.C. voltage from being applied to the said smoothing means, so as to provide a D.C. voltage in which the number of cycles inhibited from reaching the smoothing means determines the delay with which the said D.C. voltage reaches the full value at the load circuit.