delay switch help ( I think)

Discussion in 'The Projects Forum' started by Tricki, Apr 21, 2009.

  1. Tricki

    Thread Starter New Member

    Apr 21, 2009
    Hi all,

    I need some help please.

    I would like a 12v bulb in my car that comes on when the ignition is on but only for about 3 seconds. The light must go off again after the 3 seconds and not come on again until the ignition has been turned off and then on again.

    I think it would work something like a glow plug in a diesel vehicle.

    Any help is appreciated. Please be gentle I have very limited knowledge of electrics.

  2. Wendy


    Mar 24, 2008
    This circuit will do it...


    You can read more about the core part of the circuit in this article...

    555 Monostable

    What part of the world are you? It matters because different components (such as transistors) are more available in some places than others.
  3. Tricki

    Thread Starter New Member

    Apr 21, 2009

    Thanks for posting back.

    Is there something I can buy straight off the shelf?

    I am in England.
  4. tkng211

    AAC Fanatic!

    Jan 4, 2008
    You may try to get it from some electrical components shop selling relays. The device you need is called ' time delay off ' relay. You must tell the shopkeeper that the supply vpltage of the relay is 12Vdc (your car's supply voltage). If you can't find a proper one, just buy the electronic parts from some on line shop and build it. It's a simple and easy project if you have done some electronics DIY projects.