BURGLAR_ALARM_WITH_TIMED_SHUTOFF

Published:2009/7/9 21:36:00 Author:May | From:SeekIC

When S1 (sensor) is closed, power is applied to U2, a dual timer, After a time determined by C2, C1 is energized after a predetermined time determined by the value of C5, pin 9 of U2 becomes low, switching off the transistor in the optoisolater, cutting anode current of SCR1 and de-energizing K1. The system is now reset. Notice that (R6× C2) is less than (R7× C5). The ON time is approximately given by: (R7×C5)-(R6×C2)）＝tON



Reprinted Url Of This Article:
http://www.seekic.com/circuit_diagram/Amplifier_Circuit/BURGLAR_ALARM_WITH_TIMED_SHUTOFF.html

Print this Page | Comments | Reading(3)