TOUCH_PLATE_RELAY

Published:2009/7/13 3:06:00 Author:May | From:SeekIC

When 2-inch diameter disk of sheet metal or foil is firmly touched with finger, stray noise picked up by body and coupled into 10-megohm gate circuit of FET is sufficient to boost drain current to about 1.7 mA and close relay. Delayed dropout can be obtained by placing capacitor in parallel with relay coil; delay is about 0.8 s per 1000 μF of parallel capacitance.-R. P. Tumer, FET Circuits, Howard W. Sams, lndianapolis, IN, 1977, 2nd Ed., p 104-105.



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