El Cheapo 20A Lab Power Supply from ATX PC Supply

I decided to try and make a 12V, 5V, 3.3V DC power supply from the junk box. This is the result. Total cost under $5. I used a large load resistor to pull up the supply voltage and stabilize it. For a little more I could have added a voltage regulator. This one should run 10 amps all day long, max of 20A on 12v, 26A on 5v. That ought to charge your iphone!

Category:

Howto & Style

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• atx
• pc.power supply
• 12v
• 5v
• 3v
• lab
• homebrew
• diy
• convert
• ham
• amateur
• radio
• pc
• at
• genesis
• g50
• n0jrj
• iphone
• iphone 4
• iphone4
• geon0jrj
• george
• kit
• fan
• power
• supply
• resistor
• load

[m35a2lover]

i know you said you coulf run a transciever with that i have converted one for my cb radio and it works wonderful but i am however looking to get a new one with higher wattage i am going to add a very small linear amplifier and a frequency counter to my cb so i think the higher wattage will be better do you know where i could get a resistor similar to yours ?

[GeoN0JRJ]

@m35a2lover Sure. Try Mouser Electronics. They have all kinds of components. You might want to look at other plans for these power supplies and think about adding a 12v regulator IC. That way the load from an amp does not pull the voltage down. Watch the current draw from the amp to be sure you do not exceed the current rating of the Power supply. Let me know how it goes! Thanks for the post!

[GeoN0JRJ]

@m35a2lover You can order them from Mouser or digikey

[khancock70]

Sir,

I actually have a few of these power supplies. How would you add the potentiometer and the meter to vary the output?

[GeoN0JRJ]

@khancock70 I have not tried that. I have seen some other PC pwr supply videos where they use a pot to vary the voltage. Just make sure it can handle the current!

[SebastiaanLP670]

I've a normal PC power supply, and I want to make a normal supply to get energy from. can you tell me what I exactly need? So I can buy stuff in the stores? (like the types of resistors and stuff..)

thanks!

[DanFrederiksen]

good build. maybe smaller load resistor would do as well (higher resistance)

what would be really interesting is to make the supply variable

[P1001AT2]

for anyone how is attempting this project and does not have a derivation of what wire is what just open the pcu follow the wires and it will tell which is which and also the wire that turns on the pcu.

[Imperiatus]

Loved the video! I'm going to put one together myself!

[tristan2668]

to get the orange 3.3V output working, all the orange have to be touching? Cause when I connect one orange to my dc motor then to the black ground wire, my psu turns off ?!?!?!? I want 3.3V going into my dc motor.

[GeoN0JRJ]

@EwOkiE2 Well, it is rated at 34A with all the 12v supply lines in parallel so I would say give it a try!