Abstract: A circuit arrangement for monitoring a thyristor comprising an auxiliary thyristor disposed between the anode terminal and gate terminal the thyristor, and a signal generator device which contains a light-emitting diode for sending light signals to an evaluating device. In order to obtain a particularly simple and therefore functionally reliable design of the circuit arrangement, due to the elimination of a separate energy supply circuit, and to achieve emission of light signals with a particularly high light output, the signal generator device has a first pair of input terminals coupled in series with the auxiliary thyristor and the light-emitting diode is arranged between the input terminals of the signal generator device.