Introduction: DIY Lab Bench Power Supply

About: Awesome Electronics Tutorials, Projects and How To´s

Everyone has those older or newer ATX power supplies laying around. Now you have three options. You can throw them in your garbage, salvage some good parts or build a DIY lab bench power supply. The parts are dirt cheap and this supply can deliver more amps than some modern variable ones. Let's build it.

Step 1: Watch the Video!

The video gives you all explanation you need to build this project. But I will tell you the most important steps again, this way you can not screw this up.

Step 2: Order Your Parts!

Step 3: Get the Right Resistor!

You may already noticed that we have to put a dummy load on the supply to keep it stable even when we only draw small amounts of current.

I recommend the dummy load should draw at least 0.5A.

Here is the calculation if you have most of your power on 5V/3,3V rail:



Buy it here:

Here is the calculation if you have most of your power on 12V rail:



Buy it here:

Step 4: Make the Correct Connections!

What does each wire mean and where does it connect to? You can find a schematic here which tells you how to connect the parts. Anyway here is my written version of this schematic:

Orange (3,3V) ---> 3,3V red binding post

Red (5V) ---> 5V red binding post

--------------> 10Ω 10W resistor

---------------> 220Ω resistor of 3mm green LED

White (-5V) ---> -5V red binding post

Yellow (12V) ---> 12V red binding post

Blue (-12V) ---> -12V red binding post

Brown (3,3V Sense) ---> 3,3V binding post

Purple (5V Standby) ---> 220Ω resistor of 3mm red led

Green (Power ON) ---> One side of the toggle switch

Black (Ground) ---> GND black binding post

-----------------------> Cathode of 3mm green LED

-----------------------> Cathode of 3mm red LED

-----------------------> 10Ω 10W resistor

-----------------------> other side of the toggle switch

Grey (Power Good) --> not connected

If you have most of your power on the 12V rail then you need to connect a 24Ω resistor to 12V instead of 10Ω to 5V.

Step 5: Success!

Everything works! Now you can build even more awesome electronics projects with the help of this bench power supply!

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