LIGHT_CHANGE_SENSOR_DRIVES_RELAY

Published:2009/7/6 6:10:00 Author:May | From:SeekIC

Capacitive coupling between phototransistor and bipolar transistor makes circuit respond only to interruptions or rapid changes in light while ignoring normal gradual changes in ambient light as caused by clouds or at sunrise. Relay pulls in when flash of light occurs and drops out when light is removed, Use Radio Shack 275-004 miniature relay.-F. M. Mims, Transistor Projects, Vol. 3, Radio Shack, Fort Worth, TX, 1975, p 69-74.



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