ALTERNATIVE_LIGHT_OPERATED_TURNOFF_TOUCH_SWITCH

Published:2009/7/14 20:11:00 Author:May | From:SeekIC

When the touch plate is touched, it turns the output of IC1 on, giving a positive potential to the base of Q2. In turn, that turns on pins 4, 5, and 6 of IC2, triggering the SCR's gate and energizing RY1.When RY1 is energized, its contacts pull in, turning on the ac bulb. When R1 is hit by a strong light, it turns on the SCR and energizes RY1. To turn the ac bulb off, just point a strong flashlight at R2; this decreases the base resistance of Q3, making its base positive and, therefore, energizing RY2. When the contact of RY2 pulls in, it disconnects the anode of the SCR from the positive supply, turning it off. Or you can press S2 to energize RY2 and turn off the ac bulb



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