an electronic system for diverting current to a high - current load on an automobile , such as an electrically heated catalyst , is disclosed . in the system , the current of the high - current load is switched by electronic circuitry , rather than by an electromechanical relay . when current is no longer required by the high - current load , the electronic system allows current to flow to other loads on the automobile . the electronic system avoids the disadvantages presented by a relay &# 39 ; s abrupt switching of the high currents involved .