Timer Alarm Circuit
Created: Aug 29, 2014
No description available.
This circuit is a type of alarm system in which different values of resistors are used to adjust the triggering time of its buzzer. The design has fewer components than a conventional timing circuit.
The circuit is supplied by a 9V DC source. The S1 is a switch that controls the supply. The S2 serves as a triggering switch in order to start the timer. The 500kΩ, 1MΩ, 1.5MΩ and 2.2MΩ resistors are the set values to acquire 5, 10, 15 and 20 minutes intervals of time in order to produce alarm. The capacitors controls the delay of timing. The 555 IC is used as pulse generator and main component for the timer.
The design is suitable for fixed timing applications. It is cheap and easy to build.