Abstract: With a self-protect thyristor, having a MOSFET (M1) that is connected in series with the thyristor and a second, self-controlled MOSFET (M2) between the p-base of the thyristor and the external cathode (KA), several unit cells for the thyristor are arranged parallel connected in a semiconductor wafer. The voltage at the series MOSFET (M1) functions as an indicator for the overcurrent and excess temperature, and an additional MOSFET (M4) is provided where source (region) is connected conducting to the source of the series MOSFET (M1), where drain is conductivity connected with the gate of the series MOSFET (M1) and where gate conductivity connected with the drain of the series MOSFET (M1). A resistance (Rg) is provided between the gate electrode (G1) of the series MOSFET (M1) and the gate (G) of the thyristor.