Time Delay Relay Circuit

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



Notes:
1. R1 adjusts the on time.

2. You can use 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.