This is a Burglar Alarm With Timed Shutoff Circuit Diagram. Security alarms are used in residential, commercial, industrial, and military properties for protection against burglary (theft) or property damage, as well as personal protection against intruders. Car alarms likewise protect vehicles and their contents.
This circuit when SI (sensor) is closed, power is applied to U2, a dual timer. After a time determined by C2, CI is energized after a predetermined time determined by the value of C5, pin 9 of U2 becomes low, switching off the transistor in the opto isolater, cutting anode current of SCR1 and DE-energizing Kl. The system is now reset.
Burglar Alarm With Timed Shutoff Circuit Diagram
Notice
That (i6x C2) is less than (R7xC$).
The ON time is approximately given by:
(R7xC5)-(R6xC2) = Ton
