$10 DC Power Supply – 1 Day DIY

In this 1 Day DIY we take an old ATX size computer power supply and convert it into a handy, high current, DC power supply for our electronics projects.

You’ll need the following parts:
1 x Computer Power Supply
5 x Binding posts
2 x LEDs and 330ohm resistors
1 x power switch
1 x Dummy load resistor
– Heat shrink tubing

You’ll need the following tools:
-Soldering Iron
-Heat gun
-Various Screwdrivers
-Various Pliers
-Hand Drill

Recommended dummy load resistors:
New power supplies(12v): 22ohm 10W
Old power supplies(5v): 5ohm 10w

Always exercise good safety practices and common sense when working with high voltage electronics. The Recreational Engineer does not claim responsibility for any damages to person or property related to attempts to replicate the actions in this video.


James Kiricov says:

Thank you for going in to more details, as most just fly right thru it. I particularly appreciated the standby mode. I have an older model but no main power switch that came with it. Without a main power switch, the one LED lite that came with it would stay on as soon as you plug the unit in and even when you connect a switch to green and black, the LED would stay on until you unplug the AC. The details you did go over in your video was enough to fill in all the little gaps I was experiencing on my mod!

Stoica Ion Gabriel says:

Hello where in the line you solder this load resistor i see they have 2 cable but they start from where and they go where?

Ian Harwin says:

What does one do if the power unit doesn’t have a power switch? I just pulled the unit out of an old computer and it does not have a separate switch.

Andy says:

This is a great video. I am wanting to wire up a couple of railway wigwag lights in my garage. The bulbs are 12.8 volt, so why not hook them up? Right?? Great for the Man Cave and looks cool when someone comes in. I want to hook them up to my garage door opener. I bought the wigwag relay and the computer power supply, but now I wonder if I have enough power to operate the incandescent lights. The bulbs are 12.8 V and 26.9W. The power supply states that +12 has 16A. I don’t know what the Watts are.

INCC74656I says:

i would like to have a 9-15V variable supply that can output 1-150A @ 12.5V. think one of these guys would work for that and if so how do i limit hte current?

Hamza Farid says:

Bro I have 12v and 18A power supply as a charger for 12v and 100 A battery. But when I plugged the terminals it gives 1 or half ampere on multimeter why???

Ring Neck says:

Did you solder the standby led to the 3.3v brown sense? Does it need a resistor?

Jon Fisher says:

Hello! Good helpful video!! I do have a little problem though. I want to use a computer power supply to power a led panel that I made. The +12 supply which I will use is rated at 10 amps. When I hook my led panal to a 12 volt battery it draws about 6 amps at 12 volts which is correct. When I hook it up to the computer power supply rated at 10 amps in 12 volts, the voltage drops down to about 10.5 volts and it draws a little under 4 amps. I tried hooking a power resistor (5 ohm, 20 watts) to the 5 volt supply and then to ground and the voltage going to the 12 volt led panal went up to 11 volts from 10.5 volts and the current went up to about 4.7 amps from under 4 amps. So that is an improvement but still not optimum. Any suggestions? Should I put a resistor also on the 3.3 volt supply. Thanks for any help. Oh I tried using a different power supply (almost new and even more powerful) and I had the same problem so I don’t think there is a problem with the power supply. Thanks !

emil gabl says:

hello, I made a mistake of hooking up all the wires before testing the power supply to see if it was working is there a way to test the power supply to see if it is getting power…the fan doesn’t even work?

elson richards says:


Colin Dunbar says:

if you don’t have any of those big resistors you can use a 12 volt tail light bulb

Kai Peters says:

8:30 Chip n dale

Ryan Rambhajan says:

Can you connect the 12v and 3v to get 15v???…..or can you connect 2 power supply together to get double the A???

Prashanth Nayak says:

I have a similar power supply and it naturally shuts down after few moments as it senses no or least load. My question is without using the Dummy load which generates a lot of heat, Can we modify the sensing circuit and make the power supply work as normal?

Guitar Guy기터 남자 says:

Your voice is like a cartoon character you can be a good dubbing artist

Yemanebirhan Tadesse says:

wonderful! thanks so much

Adam shinny77 says:

So if my ps unit says the 5 volt side is the strongest volt line at 25 amps. Which wires would I hook to my power load resistor?

lawrence aldridge says:

can it be modified to run a burnmaster wood burning pen or a razer tip pyrograph pen forgot to ask in my last q, any helpand i mean help would very greatfull,HELP!!!!

Urchman ogboo says:

sir, if you are to power it with battery, where will you plug the wire

The Rider says:

You can use the -12v wire with the +12 and have 24v max and -5v, -3v

John Leon says:

What is the name for the type of connector/terminal you put on the front panel for the power lines?

Your Local Memeist says:

Took me 4 hours to do but it was worth it

Brandon-Lee Louw says:

Can you maybe show us how to make a power supply for a tattoo machine???

simple brian says:

hey,, thnx 4 the great work… am brian kigula brian,, am electrical engineer at MRU1 university east africa, (Uganda),,,,
hav u done some power factor measurement with any micro controller like arduino b4????
if u hav pliz help me out on how i can do it

Rochdale Surilla says:

dude can i have two 5 volt or 12 volts

boowonder888 says:

Hi again. I made my first one last year. It is from 1999 and shaped like a panini. Only 65 watts but it works without the load resistor. Also , it turned on without having to use a jump wire.
I`m ready to graduate on th project so I want to Make a second one from a 300w psu. I see you are putting the load resister between 2 yellow 12 v wires. Why not use the 5v wires? I dug up a lot of ceramic rectangular 5 and 10 w load resistors from old small TV’s. Which one should I use and why? Can you explain the function of the resistor again? Anyone may reply, just means more knowledge transference!

Tech-U-Train says:

Can you add a pot for variable resistance?

Yolin Pinacate says:

hi, dad got mad at me ’cause i “borrowed” the power supply of his beloved pc.

Scott Paige says:

My power supply has a small button which I need push before it will work. How do I fix this?

Ian Harwin says:

Great video. Any chance you could put a link to where you got the dummy load and 330ohm resistors

lawrence aldridge says:

wil this run a 10 ohms 15 volt ac pyrograph pen master burn or a razer tip pyrograph so for i have asked three other people and have not gotten any answers can you help thanks some are videos with subtitles if you could help iwould be very greatful

Roto Vicious says:

nice video, but you left out how important it is to be careful as these amounts of energy will kill. all the same very simple straight forward video i enjoyed.

paige sparkle says:

Thanks for the video. Is this too small for DIY? There have another similar 4 digital dc power supply with an attractive price on Amazon.

Nurezku says:

Or you can pay 10$ more and buy powersupply from china

emil gabl says:

hello, I made a mistake of hooking up all the wires before testing the power supply to see if it was working is there a way to test the power supply to see if it is getting power…the fan doesn’t even work?

Noah Swarz says:

Is it better to use this setup to power multiple 12v devices vs using separate power supply for each device??? Any input helps 🙂

Kendall says:

That Delta PSU you used for your first build was about 1000x the quality of the one you used in this video. I wouldn’t connect anything expensive to this one. Those cheap PSUs are called “gutless wonders” by us geeks for a reason. They lack vital parts to ensure the safety of components attached to them in a failure.

Raj nisha says:

Nice video sir

Nikola Pepic says:

What I do is that I disconnect the fan, and rewire it as a dummy load. Nothing exploded ….yet.

Raymond Hermogenes says:

Yellow is 12v. RED is 5v. What happen if I get 2 red wires then connect it to yellow wires???

Jeffrey Yeager says:

Don’t really understand that high speed gibberish.

rochat says:

Electronics are my Achilles heel, so I’m trying to learn. My question is that if the 12v source has high amperage (my supply is rated at 19a), will I fry a 12v 6a motor (for example) if I hook it up? I’m trying to wrap my head around this, so I hope it makes sense.

PlacideBolack says:

Hello have another old dell power supply to convert. This power supp0ly have 2 rail on 12v. yellow wires and white wires.. can i put this 2 rail for making one 12 v out. thx..

Jimmy Virgo says:

In my PSU im abit confused i have a grey, purple and blue that im not sure about what are they for

Phil Sheppard says:

Would leaving a Molex Connectot conected not be a good idea as it is a commonly used power connector ? Just Saying is all.

JackstandJohnny says:

It looks like these 5 phm 10 watt dummy load resistors you say we need dont exist. I cant find them on eBay, home of the chinese generic electronic component.

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