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Triggering relay with 12v

Discussion in 'General Electronics Discussion' started by pbolger, May 7, 2012.

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  1. pbolger

    pbolger

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    May 7, 2012
    Apologies for asking a really basic question, but...

    I have a rotating speaker box which requires a mains (240v ac) current to be switched via a latching footswitch to power the rotator motor. My plan is to use a small 12v psu to switch the relay. My problem is that when the footswitch closes the 12v circuit will be a dead short, and I suspect this will fry the psu rather quickly. What do I need to add to the circuit to stop this happening?
     
  2. donkey

    donkey

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    Feb 26, 2011
    if you are really concerned, try adding a LED and resistor. this will give the added knowledge the switch is working and the circuit is closed
     
  3. duke37

    duke37

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    Jan 9, 2011
    Draw your circuit showing the relay and the 12V power supply.
     
  4. pbolger

    pbolger

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    May 7, 2012
    Thanks

    That was quick! I'll give it a go.
     
  5. Rleo6965

    Rleo6965

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    Jan 22, 2012
    Small 12V relay solenoid only consumes 30ma. to activate it. This will not fry your psu. Unless you wrongly wire it.

    Show us your diagram. We might help.
     
  6. pbolger

    pbolger

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    May 7, 2012

    Thanks. Diagram attached. Please excuse my rather quick and dirty artwork...

    It's quite simple, just not sure if shorting the 12v supply is going to be a problem.
     

    Attached Files:

  7. CocaCola

    CocaCola

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    Apr 7, 2012
    You are not shorting it, the coil in the relay provides a load...
     
  8. pbolger

    pbolger

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    May 7, 2012
    Good. Better to ask than wait for that burning smell!
     
  9. davenn

    davenn Moderator

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    1,909
    Sep 5, 2009
    awwww -- where's your sense of adventure ;) ( just teasing)

    Dave
     
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