ADJUSTABLE_LIGHT_DETECTION_SWITCH

Published:2009/6/24 22:45:00 Author:May | From:SeekIC

R2 sets the circuit's threshold. When the light intensity at PCI's surface is decreased, the resistance of PC1 a cadmium-sulfide photoresistor is increased. This decreases the voltage atthe inverting input of the 741. When the reference voltage atthe 741's noninverting input isproperly adjusted via R2, the comparator will switch from low to high when PC1 is darkened. This turns on Q1 which, in turn, pulls in relay K1.



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