I am making a time delay circuit but instead of keeping the circuit on I need the delay circuit to close the other circuit after 140 secs and then to let the other circuit work until the battery expire.I am using this circuit.how can i modify it to suit my purpose?

http://www.facebook.com/l.php?u=htt...ime-delay-relay&h=a78fdrR4De6649B1T_nkfQNBpBw

 

i used this delay circuit to open a circuit for and close the circuit again after an amount of time for my earlier project. i don't know if it can help you but it was useful to me.

Time(sec)=1.1x(R1)x(C1)

R in ohms
C in farads

sorry if i can't help you.
good luck!

 

oh yeah, for the relay, use a normally closed so that when the delay circuit is on, it will open the other circuit and close it again after that.