Hey all,

I'm trying to create an RC circuit such that when the switch for the power source is closed, there is a ~30 second delay followed by a buzzer and LED that go off continuously until the switch for the power source is opened.

I've tried multiple circuits (http://teachersunderground.co.uk/Electronics/555 timer/555TIMER.pdf here is one, look at the delayed timer)

I have yet to have any luck making these. Any/all help would be greatly appreciated.

C

 

You didn't post the circuit.

 

voltage of your power source?

You could just use an off the shelf "delay on make" timer module.

http://clarkson-uk.com/555-timer/operation/frames3.html
http://home.cogeco.ca/~rpaisley4/LM555.html#29