Abstract: In an opto-electronic transimpedance amplifier for the amplification of optical signals supplied by a photovoltaic cell and having a transistor as amplifier, the load resistor of the amplifier transistor is a transistor and two ohmic resistors whose series connection is parallel to the emitter-to-collector path of the load resistor transistor and whose connection point is connected to the base of the load resistance transistor.

Abstract: A circuit arrangement for actuating semiconductor lasers with the transmitted optical power being controlled with the aid of a photodiode optically coupled to the laser radiation, whose amplified photoelectric current controls the current of the laser in such a way that its radiation capacity remains constant, is to be improved, in particular, such that the circuitry expenditure is low, the band width large and the operating point of the laser easy to set, and, furthermore, such that a digital or HF signal for modulation of the laser radiation can be coupled without difficulty.