555 amplification exposure time automatic controller circuit

Published:2011/5/24 2:53:00 Author:TaoXi | Keyword: amplification, exposure, time, automatic controller | From:SeekIC

As the figure 17-10 shows, the controller circuit is composed of the step-down rectifier circuit, the monostable delay circuit and the relay control circuit. When the controller is amplifying the photo, it can automatic detect the thickness of the negative film to decide the exposure time.The monostable timing circuit is composed of the IC(555) and the photosensitive detection head R0, the C1～C4.etc. The timing length is determined by the circuit's charge-discharge time constant. The photosensitive detection head uses the photoconductive resistance, K2 is the toggle switch and it has four kinds of exposure method, 1,2,3 tap positions are the automatic control, there is three kinds of exposure value: light , normal and dark , the fourth gear is the manual control gear.



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