| 摘要 |
A receiver for responding to a light beam, especially from an optical fibre light guide, includes a photo-diode which responds to the light of the beam, and which is connected to the input of an amplifier. The output current of the amplifier flows through a light-emitting diode and a resistor in series, with the output taken across the resistor. The light emitted by the light-emitting diode is received by a second photo-diode connected to the amplifier's input. Thus the light-emitting diode - photo-diode combination forms an optical isolator in the amplifier's feedback loop. This relatively simple circuit avoids difficulties inherent in known devices where, for instance resistors and capacitors may be in the feedback loop. <IMAGE> |
