Time delay Relay circuit with IC555

Time Delay Relay with IC555 circuit

Parts List

C1    10uf 16V Electrolytic Capacitor
C2         0.01uf Ceramic Disc Capacitor
R1           1  Meg Pot
R2       10 K 1/4 Watt Resistor
D1,D2        1N914 Diodes
U1         555 Timer IC
RELAY          9V Relay
S1          Normally Open Push Button Switch

Remark:
1. We used R1 adjusts the on time.

2. You can get a different capacitor for C1 to change the maximum on time.

3. S1 is used to activate the timing cycle. S1 can be replaced by a NPN transistor so that the circuit may be triggered by a computer, other circuit, etc.