Circuit for controlling energization of a direct current load

Claim 1

A CIRCUIT FOR CONTROLLING THE DIRECT CURRENT ENERGIZATION OF AN ELECTRICAL LOAD FROM AN ALTERNATING CURRENT SOURCE COMPRISING A CONTROLLED SEMICONDUCTOR RECTIFIER HAVING A GATE ELECTRODE, SAID RECTIFIER BEING ADAPTED TO BE CONNECTED BETWEEN SAID SOURCE AND SAID LOAD, FIRST MEANS ADAPTED TO BE COUPLED TO SAID LOAD FOR DERIVING A UNIDIRECTIONAL CONTROL SIGNAL INDICATIVE OF THE OPERATION OF SAID LOAD, CONTROL MEANS RESPONSIVE TO SAID CONTROL SIGNAL AND OPERATIVE TO PRODUCE AN OUTPUT SIGNAL COMMENSURATE WITH THE DEVIATION OF SAID CONTROL SIGNAL FROM A PREDETERMINED CONDITION SECOND MEANS ADAPTED TO BE COUPLED TO SAID SOURCE FOR PRODUCING A VARYING SIGNAL, FIRING MEANS COUPLED TO SAID SECOND MEANS AND TO SAID CONTROL MEANS FOR COMBINING SAID OUTPUT SIGNAL AND SAID VARYING SIGNAL TO PRODUCE A FIRING PULSE AT A TIME DETERMINED BY THE CHARACTERISTIC OF SAID OUTPUT SIGNAL, AND MEANS COUPLING SAID FIRING MEANS TO SAID GATE ELECTRODE TO CAUSE SAID RECTIFIER TO CONDUCT IN RESPONSE TO SAID PULSE.