12vac to 12vdc

Discussion in 'The Projects Forum' started by jerrymyersmills, May 26, 2011.

  1. jerrymyersmills

    jerrymyersmills Thread Starter New Member

    Joined:
    Mar 22, 2011
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    Dear friends
    i have bought a 12VDC relay for project work.The line voltage is 220VAC so i bought a 12V transformer to convert the 22ov into 12V for smooth operation of the relay but i keep hearing this BUZZING sound anytime the relay is working.
    Folks i am a bit confused.
    I suspect that the transformer is supplying 12 VAC to the relay instead of 12VDC.I want to convert 12vac into 12VDC and need some assistance to be able to achieve this.
     
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  2. SgtWookie

    SgtWookie Expert

    Joined:
    Jul 17, 2007
    22,158
    1,678
    Your DC relay may have a diode across its' coil. That would short out the transformers' output for 1/2 of the cycle.

    You can get a small full-wave bridge rectifier from your local Radio Shack store for around $1.39+tax.
    http://www.radioshack.com/product/index.jsp?productId=2062581

    It has four leads; two are AC (indicated by ~) and the other two leads are DC, marked + and -. You just connect it up. If the relay still buzzes, you may need to add a filter capacitor across the bridge output. This would probably do the trick:
    http://www.radioshack.com/product/i...Name=Type&filterValue=Electrolytic+capacitors
     
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  3. madhusudan.pigeonsembs

    madhusudan.pigeonsembs New Member

    Joined:
    Mar 17, 2011
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    You can follow this attachment.......
    I think you will be very much clear......
     

    Attached Files:

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