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Car PC swich

Discussion in 'Automotive Electronics' started by shahabmusic, Jan 23, 2009.

  1. shahabmusic

    shahabmusic New Member

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    Hi

    guys its more than 6months im looking to find a way to fix this problem but I couldn't find anyone who can help me.
    I don't know anything about electronic except very simple stuff.

    I have installed a PC inside the car but I need the pc turns on whenever I turn on the car and turns off whenever I turn off the car.

    I replace the PC power switch with a relay so whenever I start the engine power goes to relay and relay acts as switch and my pc turns on. in real world when you decide to turn your pc on, you push the power button for less than a second and then you release it but now when I turn the car, relay starts working and never turn off until I turn off the car.

    I need a electronic circuit or a part that put power into relay for less than a second when I turn on the car, and put power into relay again for less than a second when I turn the car off.

    Hopefully I could say what I meant. Sorry for my bad English.
     
  2. KMoffett

    KMoffett Well-Known Member

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    The attached will give you a momentary contact closure when powered up. The ON time depends on the relay coil resistance and the value of capacitor C1.

    Ken
     

    Attached Files:

  3. shahabmusic

    shahabmusic New Member

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    Thank you very much for reply but I think in this diagram when I connect power into this circuit, the relay starts clicking until I disconnect the power from circuit. is this right? I need when I connect the power, the relay clicks just once and when I disconnect the power the relay clicks once again.
     
  4. dave

    Dave New Member

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  5. KMoffett

    KMoffett Well-Known Member

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    No. When you power up this circuit, the relay contacts close for a short period, until the capacitor charges. Then they open, and stay open until the power is removed. What makes you think it will start clicking?

    Ken
     
  6. shahabmusic

    shahabmusic New Member

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    my bad:D yes you are right. thank you very much for help.
     

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