- Published in issue 7/1999 on page 58
Electronic circuits must never be operated with an excessive supply voltage. Such a situation may be prevented with the protection circuit shown in the diagram. If the current through the IC becomes excessive, or the IC overheats, an external silicon-controlled rectifier (thyristor), Th1, is triggered, whereupon the supply voltage is short-circuited. This causes the current limiting in the power supply to be enabled or the relevant fuse in the supply to blow. Whatever, the circuit being supplied is protected.