How can I modify a computer power supply to use for powering a solderless breadboard for projects?

I'm trying to use a surplus computer power supply to use on my breadboard for projects but I can't figure out how to get it to sense an action to power up. I'm trying to not go out and buy a regulated power supply from Fry's for @ $30-50. I probably have like 4 power supplies laying around, so I'm just trying to put them to use instead of throwing them out. Or, Where do I go on-line to talk to someone find that kind of information?

6 Answers

  • Bjorn
    Lv 7
    1 decade ago
    Favorite Answer

    You would have to set up some kind of switch for the power supply to get it to turn on when you wanted it to.

    Generally, it is the 3rd pin on one row of pins and the 4th pin on the other row. This would be a green colored wire and a black colored wire.

    Just do a google search for what you are looking to do, there are plenty of people who use computer power supplies for just such a thing.


  • Anonymous
    1 decade ago

    There are live 12v and 5v supplies to the motherboard constantly, this is used for sensing activity as in operating the switch. For the average electronics project these may suffice.

  • Anonymous
    1 decade ago

    Most power supply's (especially older ones) need some load to start functioning. Anything like an old drive, hard or floppy, will get the job done.

  • Joe M
    Lv 5
    1 decade ago

    You will be much better off with the regulated power supply.

    Get one - you won't regret it.

    Maybe see if you can throw the old computer power supplies up on e-bay and get a few dollars towards one.

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  • 4 years ago

    If the pump draws 32A, you are not going to want to use a power supply that is not capable of supplying at least 32A. If you do, you are going to likely cause a fire hazard as the pump will try to pull 32A and the PSU will overwork trying to provide those amps.

  • 1 decade ago

    The power connector on smps has 2 voltages +5v and +12v

    the red wire is +5v the yellow wire is +12v the black is gnd. the voltage between the red wire and black wire is +5v the voltage between the yellow and black wire is +12v their is no common ground its a floating ground watch your current draw.

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