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FLUORESCENT LAMP LIGHTING CIRCUIT IN READER FOR FACSIMILE OR THE LIKE
FLUORESCENT LAMP LIGHTING CIRCUIT IN READER FOR FACSIMILE OR THE LIKE
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机译：阅读器中的荧光灯照明电路，适合喜欢或不喜欢的人
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摘要
PURPOSE:To obtain an excellent picture without deteriorating S/N by controlling a fluorescent lamp current through a light quantity detection output and detecting light quantity and a surrounding temperature so as to raise an alarm signal to the deficient light quantity at a high temperature. CONSTITUTION:Light of a fluorescent lamp 1 is formed on a CCD3 through a reflection mirror 12 and a lens 13. The CCD3 outputs a signal having a level in response to the amount of light reception, this output signal is fed to a peak hold circuit 10 through an amplifier 5 and peak level is held. The peak level is compared with a reference voltage V1 at a comparator 6, and when the peak level is larger than the V1, an output of a flip-flop 11 goes to an ''H'' level to reduce a tube current of the fluorescent lamp and when smaller, the output goes to an ''L'' level to increase the tube current. On the other hand, when the ambient temperature reaches a prescribed value or over, since the potential at a point P is lower than a reference potential V2, an output of a comparator 7 goes to ''H'' level and an alarm signal is outputted.
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