| 摘要 |
A preamplifier circuit is disclosed for use with a photoconductive sensing device having a conductance linearly dependent upon incident photon flux. A forwardly biased diode, which in the preferred embodiment comprises a transistor having a commonly connected base and collector, is coupled to one terminal of the photoconductive sensing device. An output transistor is connected to the sensing device and the diode to provide an output signal dependent upon the magnitude of incident photon flux upon the sensing device. This output signal is not dependent upon the magnitude of conductance of the sensing device, and thus the present circuit may be used in a photoconductive sensor array to eliminate the requirement of sensor alignment. A plurality of series connected diodes are connected between a source of bias voltage and the output transistor to provide a selected constant gain to the output signal.
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