This is my first time posting on this site so first of all let me say hello to everyone. I think this will be a very simple problem for most of you but I am electronicly challenged so I can't seem to figure it out. I have a simple light bulb circuit (+ on one side - on the other) What I need is some sort of timer. When 12 volts hits it I need for it to stay on 8 seconds and go off. I need it to do this same thing every time the power is cycled. I have tried different variations of a resistor and capacitor but can't get the results I'm looking for. I have been working on this problem for weeks and I'm begging for help. Thanks

 

You will need an active device like an LM555 timer for this function. Do you know the current draw of the bulb?

 

and are you saying that the input "control" signal is 12v?

Will the input be gnd (like the output of another device) or floating (like one side of an open switch) and when this signal switches to 12v, you want the light bulb on for 8 seconds?

 

If you'd like the delay adjustable, and the bulb to gradually dim as it goes out, here's a circuit for you:
http://www.csgnetwork.com/dimmerdelayproj.html