using transformer coupling

Electronic switching or gating, i.e. not by contact-making and -breaking > characterised by the use of specified components > by the use, as active elements, of semiconductor devices > Bipolar semiconductor devices with more than two PN junctions, e.g. thyristors, programmable unijunction transistors, or with more than three electrodes, e.g. silicon controlled switches, or with more than one electrode connected to the same conductivity region, e.g. unijunction transistors > with galvanic isolation between the control circuit and the output circuit > using transformer coupling

Electronic switching or gating, i.e. not by contact-making and –breaking (gated amplifiers H03F3/72; switching arrangements for exchange systems using static devices H04Q3/52) > characterised by the components used (H03K17/04 - H03K17/30, H03K17/94 take precedence) > by the use, as active elements, of semiconductor devices (using diodes H03K17/74) > having more than two PN junctions; having more than three electrodes; having more than one electrode connected to the same conductivity region > with galvanic isolation between the control circuit and the output circuit (H03K17/78 takes precedence) > using transformer coupling