Abstract: An electrical converter equipment for providing a d.c. voltage from an alternating current source. The converter has a unique operating cycle wherein a variable control angle is effected. The operating cycle for the converter comprises a series of half periods of the alternating current source. During different periods of time, the converter operates with different control angles. The control cycles comprise n periods of the input signal, where n is an odd number not less than three. During two half periods of a cycle, the control angle is varied. During two other half periods of the cycle, the converter operates at a fixed control angle. The half periods during which the converter is controlled with a variable control angle are time equidistant.