Newbie Question -- how do relays work

Discussion in 'General Electronics Chat' started by Bjorn, Apr 29, 2011.

  1. Bjorn

    Thread Starter New Member

    Jun 29, 2009
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    I understand the basic princibles of a relay switch but I am confused about how the armature moves back and forth. Using a direct current how does the current get shut off and allow the armature to go back in its original position?

    I wired up a spdt relay and it keeps clicking so what shuts off the magnent? Thanks.
     
  2. nerdegutta

    Moderator

    Dec 15, 2009
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  3. t06afre

    AAC Fanatic!

    May 11, 2009
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    What kind of realy is it (type, serial number etc). And what do you use to power it. It could be that the relay draw to much current from you power supply.
     
  4. hgmjr

    Moderator

    Jan 28, 2005
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    You may also want to read the material on relays contained here in the AAC ebook. It will add to the information in the material already suggested.

    hgmjr
     
  5. Bjorn

    Thread Starter New Member

    Jun 29, 2009
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    Isnt it supposed to click? I picked it up at Radioshack, it is a 9v relay. I used a 470 uf capacitor and it slowed the clicking down considerably. From what i've read I assume the magnent attracts the armature to move. After the armature moves this cuts off the current thus the magnent has no effect on the armature. So what pulls the armature back into place? Is it a spring?
     
  6. KJ6EAD

    Senior Member

    Apr 30, 2011
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    Yes, most simple relays have leaf or coil springs to return the armature to it's off position.
     
  7. mbxs3

    Active Member

    Oct 14, 2009
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    The relay should only be clicking when it is being energized or de-energized. If you have 9v going to the relay coil and a good ground then the relay should not be constantly clicking. The clicking you are hearing is the mechanical movement of the mechanisms in the relay because of the presence or lack of electromagnetic force.
     
  8. BillB3857

    Senior Member

    Feb 28, 2009
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    Do you have the normally closed (NC) contacts in series with the coil? If so, as soon as it energizes, it will self de-energize and act like a BUZZER!
     
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