| 摘要 |
PURPOSE:To change optionally and simply the power of the output electric current of a photoelectric converting means by converting to the photometric signal of the desired power of the output electric current of the photoelectric converting means. CONSTITUTION:The circuit consists of a photoelectric converting means, the first logarithm compressing means to output the output electric current of the photoelectric converting means as the logarithm-compressed voltage, the second logarithm compressing means to output the output electric current of a constant electric power source as the logarithm-compressed voltage, and an amplifying means to amplify and output the difference voltage between the output voltage of the first logarithm compressing means and the output voltage of the second logarithm compressing means by the amplifying ratio set in accordance with the desired power of the output electric current of the photoelectric converting means. For example, a silicon diode 1 is equivalent to the photoelectric converting means, transistors 2 and 16 for compressing the logarithm and operation amplifiers 3 and 17 are equivalent to the first logarithm compressing means, constant electric current sources 4 and 13 and transistors 5 and 14 for compressing the logarithm are equivalent to the second logarithm compressing means, and a resistance 6 to a transistor 12, a resistance 18 to a transistor 25 and an analog switch 26 to a transistor 34 for compressing the logarithm are equivalent to the amplifying means respectively.
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