Circuit arrangement for monitoring the operating range of an operational amplifier

The invention relates to a circuit arrangement for monitoring the operating range of an operational amplifier (OP). For this purpose, the operational amplifier (OP) is followed by a rectifier bridge circuit (D1...D4) in the DC branch of which the light-emitting-diode section of an optocoupler (OK) is arranged. A monitoring circuit (ÜS) is used for detecting when the phototransistor of the optocoupler becomes conductive. A fault indication can then be triggered. The operating range of the operational amplifier to be monitored is set by a Z diode (Z) which is connected in series with the light-emitting-diode section of the optocoupler. To protect the light-emitting diode of the optocoupler against overload, a series resistor (RV) can be additionally connected in series with the light-emitting-diode section of the optocoupler and the Z diode.