Protection of an alternating current switch

摘要

The circuit (25) has comparators (37, 39) assigned to halfwaves of signs of an AC power supply to receive reference voltages setting respective thresholds on reference inputs (40, 43). An input stage provides a voltage proportional to a voltage across a bidirectional switch to respective read inputs of the comparators. A resistor (41, 44, 45) introduces a voltage drop between terminals of the switch unit and inputs.