DIY Bench Supply





Introduction: DIY Bench Supply

About: I live on Venus. Check my location for more info and tell Deltronn Connections to fix their Internet beacon in the Alhora Mountains! OK on a better note, I have got A collection of ancient video games. I hav...

Here is a hobby/work bench power supply for those poor folks out there. It was taken from an old tower PC running Windows Millennium. For a size comparison, I put a Raspberry Pi next to it. It is completely free and only requires some electrical tape, a knife and a multimeter to get it going. I got this ATX power supply from the computer I pulled out of the garbage bin. Enjoy the hack!

Step 1: Slicing Wires

All of these ATX power supplys have connectors that would hook up to the computer's components. You will need to cut these off as close to the end as possible. When you're done, it should look like the picture above.

Step 2: Make It Turn On

That's right. You will see a green wire that you need to strip and twist together with a ground wire. If you don't do this, your power supply won't turn on.

Step 3: Tape It Up!

Now, take the electrical tape and sort out the wires according to color. When that is done, you need to tape the wires together. Look above for a visual aid. Tape the grey wire, purple wire and blue wire's off and make sure they don't touch any other wires. just keep them out of the way. I have found no use for them.

Step 4: Voltages

I've found with my multimeter that the voltages of the wires are this:

Red wire: 5 volts.

Orange wire: 3 volts.

Yellow wire: 12 volts.

Black wire: Ground.

Take your own multimeter and test the wires. You can follow my test results but remember, I'm not responsible if you fry your RPI using this result chart.

Step 5: Strip

Now take the knife or a wire stripper and cut off the ends of the wires. You can strip them all or just one wire of each kind. I find that by only stripping one wire of each kind, the others will stay away from that chance of short circuiting some stray wires.

Step 6: Make a Guide (Optional)

You can take the wires with a piece of cardboard and poke a hole in the cardboard for some wires. iThen write down the voltages below the wires for reference. I don't do this, I just remember what wire goes where when I test something. I don't mind the wires not being harnessed. (No photos because I didn't do this)

Step 7: Use Your Power

Just plug the power supply into a computer cord. It should start right up. Please note that it has been suggested that you should add a 200 ohm resistor between a 5 volt wire and ground to keep the supply from turning off. I've never had trouble with this. Test and power stuff with some aligator clips or extra wire. (Above I tested my tiny screen from the Simple Camcorder Viewfinder Hack) If you're feeling really geeky, you can even take an adjustable stereo volume knob to control the voltage coming from the supply. You may even wire a screen to display what voltage is being put out. Enjoy your new toy!



    • Water Contest

      Water Contest
    • Creative Misuse Contest

      Creative Misuse Contest
    • Oil Contest

      Oil Contest

    7 Discussions

    I forgot the fire cracker that explodes when something goes wrong...

    Simple, but usefull! (some Atx's need a minimum power consuption to work. So i should attach a (200 ohm 10 w) resistor between an output wire and a ground.. maybe its a good idea to add this to your instructable :) )

    1 reply

    Thank you! I added this little reminder although I never had trouble with it. Maybe I just didn't get my hands on the headache I thought it would be...


    1 year ago

    Nice! These things get tossed daily and could be still useful.
    Do you know how many amps/watts it supports on each secondary?

    1 reply

    3 volts gets 1 amp, 5 volts gets 4.26 amps and 12 volts cut my multimeter off. I'm guessing that it is about 10/13 amps for 12 volts. My multimeter can't read the watts, so I need to get a better multimeter. Thanks for reading!


    1 year ago

    missing pictures. bad cable isolation. you could put a switch between the blue and the black cable. no resistor to keep the power. supply alive when it have no load. rpi on picture that's not even used

    1 reply

    I am sorry about that. I didn't consider this: I added some pictures, I
    never even really needed cable isolation and the supply never shut off
    unless I unplugged it. Oh, the RPI was for a size comparison. (I added
    that line after seeing this comment) As soon as I can get a switch, I'll add it to the tutorial. Thanks for the pointers though! I really appreciate it.