Power Supply

Discussion in 'General Electronics Chat' started by ELECTRONERD, Jul 24, 2009.

  1. ELECTRONERD

    Thread Starter Senior Member

    May 26, 2009
    1,146
    16
    Hey Everyone,

    I have a power supply that can give about six or seven amps of current and I need eleven amps. Could I put it into a power transistor to amplify the current to obtain eleven amps? I know that eleven amps is quite a bit of current, but it's what I need. Are there any power transistors out there that are capable of supplying the current I need? If there is, how would I accomplish this? On the other hand, if a power transistor can't do this, what would recommend I do?

    Thanks!
     
    Last edited: Jul 24, 2009
  2. millwood

    Guest

    you can get a new PS, you can modify the existing PS.
     
  3. ELECTRONERD

    Thread Starter Senior Member

    May 26, 2009
    1,146
    16
    Shucks, I can't implement the transistor to regulate 11 amps?
     
  4. ELECTRONERD

    Thread Starter Senior Member

    May 26, 2009
    1,146
    16
    Would I have to do much to the power supply?
     
  5. Wendy

    Moderator

    Mar 24, 2008
    20,765
    2,536
    I've thought of making my own supply, using two of these as a base. You can also parallel them, with care.

    The core problem you face is you need 11 amps from somewhere. A SMPS will do it, as long as the wattages match and you allow for some losses. The base concept of DC/DC conversion has come a long way in the last decade or so, drop the voltage, raise the current.
     
  6. millwood

    Guest

    it depends on how the power supply is designed.

    for a "linear" power supply, you are talking about brand new transformers, bigger diodes / bridge, bigger transistors and bigger heatsink.

    for a switching mode power supply, you may have to rewind the transformer, redesign the protection circuitry, and use bigger diodes.

    unless you absolutely have to reuse the existing PS, it would be cheaper to sell the existing PS and get a new one.
     
  7. Ratch

    New Member

    Mar 20, 2007
    1,068
    3
    ELECTRONERD,

    Been there, done that over 30 years ago. Follow the sequential links and see how you can use a big resistor to dissipate most of the heat from high current and voltage away from the transistors. One transistor is in series with the resistor and one is in paralled. Look at the neat circuit the folks at Hewlett Packard came up with. I can verify that it works because I used it.

    Ratch

    http://forum.allaboutcircuits.com/showthread.php?t=24714&highlight="power+supply"&page=3 see post #25
     
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