Abstract: A sensor system for recording the ambient conditions of an optical sensor having a transmitter unit and a receiver unit linked by an optical gap. An electronic sensor unit is provided that predetermines a basic setting of the optical sensor independent of the ambient conditions. The electronic sensor unit contains a signal processing section with comparators for comparing a reception signal of the optical sensor with threshold values corresponding to certain ambient conditions. The electronic sensor unit recognizes and evaluates changes in the ambient conditions as a function of the comparing, and restores the basic setting of the optical sensor such that the sensor system dependably reacts to subsequent changes in the ambient conditions.

Abstract: An H.F. broadband amplifier comprises a transistorized differential amplifier input stage the potential of which is set by a voltage divider circuit, and an additional transistor for attenuating a.c. signals present at the input of the amplifier in its turned off stage, the emitter-collector parts of the additional transistor being connected into a collector current circuit of a transistor of the differential amplifier, and the base of the additional transistor being operated in base connection, and switched to a reference potential of low resistence in HF terms to reduce the capacitative coupling between input, and output of the amplifier circuit.