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Schematic needed For PSU 13.8V @ 5A Regulated

Discussion in 'Electronic Design' started by Pyro_Dan_Downunder, Jan 15, 2005.

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  1. Hello All,

    I was wondering if anyone knew of somewhere or could draw up a
    schematic for a 13.8V 5A Regulated Power Supply? Any help would be
    greatly appreciated.
    Cheers.

    Downunder Dan

    It was through his shocking misfortune he found a weak spot in the
    wall....
     
  2. mike

    mike Guest

    This is a catch-22.
    If you need to ask this question, you probably don't want to start with
    a switcher.

    For a linear supply, your biggest problem is gonna be acquiring the
    transformer. If you have to buy it new, you'd be much better off buying
    a whole used power supply.
    Your only economic choice is to obtain a surplus transformer and design
    around it.

    The cheapest/most available transformers come from 12V battery chargers.
    But they don't put out quite enough volts for a simple design at 13.8V
    ....unless
    there's enough space to add a few turns. And they sometimes have rather
    high output impedance optimized for charging batteries.

    While you can easily draw a schematic, the devil is in the details.
    You need something that won't quit when the line voltage droops, or melt
    when it peaks. Current limits? Overvoltage protection? Input spike
    protection.

    This question comes up a lot in the ham radio newsgroups. People spend
    weeks building a supply that saved them 10 bucks then hook it up
    to a $1000 radio. If the supply shorts, poof goes the radio. Or if you
    get really lucky, burns down your house. False economy.

    If you decide to do this and you are gonna power something you value,
    make sure you evaluate the hell out of your design. You're gonna need
    a wideband oscilloscope and a means to apply transient loads at a rate
    sufficient to view on your scope.

    Anybody who tells you power supply design is easy has never tested one
    thoroughly.
    mike





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  3. Jeff

    Jeff Guest

    Computronics (Perth) have a meanwell S-60-12 which you can adjust up
    to 13.2V, for 32.50AUD... if that voltage is good enough the price
    makes a mockery of the cost of building one yourself.
     
  4. Mark Jones

    Mark Jones Guest

  5. Don't let potential get in the way of your life!
     
  6. Don't tell your kids they have "great potential" unless you want them to
    turn out like me.

    "Oh, you have so much potential! (why are you such a disappointment?)"

    Good Luck!
    Rich
     
  7. Thanks for the explanation. I had wondered how it happened.
     
  8. Brian

    Brian Guest

    If you really want to make your own power supply, take a look at
    http://www.fncwired.com/13_8VoltExample/ , drawn up for you.
    Brian
     
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