Help with 5v-12 trigger relay

Discussion in 'General Electronics Chat' started by NormL, Dec 11, 2013.

  1. NormL

    Thread Starter New Member

    Dec 11, 2013
    2
    0
    Hi

    I have a Pioneer radio with a 5v DC output and I have installed in the back of my cabinet 3 12v PC fans (for cooling purposes) These are activated with a wall switch. I would like to have, (when I switch on the radio) the 5v output of the radio to trigger a 5v-12v trigger relay that I bought already, so that the fans will come on automatically. I have been trying to connect the leads of a 12v DC output to the relay but since I am no genius.
    IT DOES NOT WORK....

    Here is a somewhat image of the switch, mine has no signs. all I know is that the 5v leads are separate.

    http://dmohankumar.files.wordpress.com/2012/04/5v-spdt-relay-connection.jpg

    Question: Where do I connect the 12v input leads and also where do I connect the output ones for the load.

    Maybe a simple problem

    Thk

    NormL
     
  2. #12

    Expert

    Nov 30, 2010
    16,355
    6,852
    A and B get the 5 volts. 1 and 3 form a single pole switch, and that is all that is necessary to run the 12V to the fans. The 3 fans will have a second wire for, "ground" or, "common" of the 12 volt supply. There is no need to switch those wires on and off. Just leave them connected.
     
    Last edited: Dec 11, 2013
  3. MaxHeadRoom

    Expert

    Jul 18, 2013
    10,571
    2,382
    It may be advisable to use both contacts by paralleling them, I think they are a bit over confident on the rating, they seem really small relays to have 8amp rating, if anything this will be a resistive load, any thing slightly inductive would be better to use both contacts if the other is free?
    Max.
     
  4. NormL

    Thread Starter New Member

    Dec 11, 2013
    2
    0
    Tks guys

    Will check it out
     
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