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Simple power supply question

  1. Jan 25, 2015 #1
    I have a power brick (transformer) that sends 12V, 17.9A to a device. I have another device that requires 12V, 10.83A. If I put a 1.7 ohm resistor in parallel to draw some of the current:

    [itex]\frac{12V}{17.90A-10.83A}=1.697312[/itex]

    Could I use it to power the 10.83A device? I'm just not sure if it is as simple as that.

    Also, when it says 17.9A on the transformer, does that just mean that is the MAX current that can be drawn, or is that what it is always sending?

    Edit: Sorry I should add that it is an external power supply, so it is outputting DC not AC.

    Thanks
     
    Last edited: Jan 25, 2015
  2. jcsd
  3. Jan 25, 2015 #2

    davenn

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    Gold Member

    no you don't need all that

    Just power the 12V 10.83 A device off the 12V 17.9A supply .... the lower current device will only draw what it needs from the 12V supply


    That's the max it can supply, and preferably you never want to push a PSU to its max


    yup I guessed that, tho my earlier answer wouldn't have made any difference


    cheers
    Dave
     
  4. Jan 25, 2015 #3
    Oh Ok. Thanks a bunch Dave!
     
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