Simple 555 timer delay on circuit needed

Discussion in 'General Electronics Chat' started by eatumup, Feb 20, 2008.

  1. eatumup

    Thread Starter New Member

    Feb 20, 2008
    3
    0
    Hi all,
    I am sure that this has been asked a million times before or is so simple its silly to ask. But after browsing for about 2 hours I dont think i have quite found what im looking for.

    I am trying to use a simple 555 tier circuit to activate a relay. Ill be using this on a 12 volt automotive circuit. Basically what i want this to do is:
    When turned on (applying a consistant 12v) it will close a N/O relay for about 1-2 seconds then open the realy back up (remove power) and remain in this state until power is completely removed from the system thus, resetting it.

    as for the application here is what i intend on making it do. when first turned on I want to have the relay trip two more 12volt relays. the first would trip a N/O relay lighting a 12 volt automotive bulb for the timed durration. The second relay would be a N/C relay that would deactivate a second automotive lighting controller while the single bulb is lit

    I have tried doing this in the past using a 555 timer and a 9v reed relay, but I dont think i properly understand the concept of the 555 timer. as a result my attempts have made the circuit automatically reset and recycle on its own. So i think its best to forget what i started using, and hope you experts can show me a way to do this right.

    Probably the easiest solution would be to buy a time delay relay off the shelf, but the ones ive found have been quite expensive or bulky. Id like to be able to put this in a small enclosure if possible. Im open for other ideas than the 555. But the bottom line is that im looking for simple inexpensive way to do this.

    Thanks
    James
     
  2. hgmjr

    Moderator

    Jan 28, 2005
    9,030
    214
    Try looking at this webpage on 555 timers.

    Then you may want to take a look at Dave Johnson's website at www.discovercircuits.com. Searh the schematic section with the keywords 555 and timer.

    hgmjr
     
  3. eatumup

    Thread Starter New Member

    Feb 20, 2008
    3
    0
    Thanks! That information was a lot of help. Hopefully I will be able to better understand what i am doing with this circuit. In fact the first link shows a one shot timer. And from what i read, it sounds exactly what im looking for. so all i think i have to do is adjust the RC constant and i should have what i need.
     
  4. eatumup

    Thread Starter New Member

    Feb 20, 2008
    3
    0
    Sorry about the misplacement of the post. I meant to put this in the projects section.
     
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