Abstract: The invention relates to a system for processing an electrical power supply signal for a resistive heating element.The circuit provided comprises an a.c. current source, a rectifier and a chopper for supplying the resistive element with a current having two superimposed components one being d.c. and the other being a.c., both at a variable voltage.The invention applies particularly to the supplying, with a signal thus processed, of the resistive element of a connecting piece for electro-weldable plastic tubes, of an electro-heating envelope for the connection or protection of pipes, or of a heat-shrink sheath for operation on a cable having a conductor or conductors used for the carrying of electrical energy or for telecommunications.