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.
This is a basic application of 555 timer. It is used as part of the
timing circuit in which it varies time interval with respect to the
value of resistance given. It is useful for simple application where
fixed timing is needed.
The complete design is provided at
link-> http://schematics.com/project/timer-alarm-circuit-14342/
Project Description
Figure 1 Timer Alarm Circuit 1
Figure 2 Timer Alarm Circuit 2
The complete design is provided at
link-> http://schematics.com/project/timer-alarm-circuit-14342/
