$8 DIY Variable Digital Power Supply




About: Hi, I'm Tamas (Thomas), a 19 years old Hungarian guy. My hobby started more than 10 years ago. I learn electronics, physics, programming, IoT and I'm sharing my projects with you, hope you like it!

Hi in this instructable I'll show you that how can you make a variable 12v power supply, that can be used to design electronics projects or as a project power supply. The device is based on the LM2596 NC Voltage Switching Regulator, that is a very effective integrated circuit. I bought mine from Amazon with a voltage display. It's easy, and very glad to use. All link appears in the "Parts" step. Of course you can use this circuit for battery charging, powering up an electronicts project. I think every hobbyist needs a lab bench power supply, but I'm usually using Arduino for my project and I don't work with more then 12 volts, so I don't want to buy an expensive lab bench power supply. That's why I made this cheap and simple power supply. For me cost only 8 bucks because I should buy only the main circuit that was 7.99 dollars. But almost every hobbyist has the other parts in his inventory.

It's easy to use there are four buttons:

  • if you press "+" the voltage will increase with 0.1 volt, if you press and hold the voltage increases with 1 volt
  • if you press "-" the voltege decreases with 0.1 volt...
  • if you press "I" the build in voltmeter measures the input voltage
  • if you press "O" the voltmeter measures the regulated output voltage

The maximum current of this circuit is 2A, this is more then enough to power up Arduinos. It's simply amazing! Now let's see what else will you need!

Step 1: Parts and Tools


  1. Soldering Iron
  2. Glue Gun
  3. Wire Cutter/Stripper


Step 2: Step 1

Use your soldering iron and and solder one short and one longer wire to the DC barrel input jacks. Usually the positive pin is on right and the negative is on the left (look at the 3rd image).

Step 3: Step 2

You should use agian your soldering iron to solder the crocodile clips to the DC barrel jack. If you want you can connect the crocodile clips directly to your circuit, but I think this is a better solution.

Step 4: Step 3

Use your srewdriver and connect the cables to the circuit.

Step 5: A Quick Test

Power up the circuit and try it out. Mine works fine.

Step 6: Step 4

Now you are close to finish this project, just glue the parts on a plastic sheet just like me. Well, you can make a better case, but isn't neccesary. I wanted to make this gadget portable, this is very important for me. When I'm working with Arduino I need sometimes a small and portable power supply.

Step 7: The End

Thanks for watching, I hope you liked!



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    17 Discussions


    1 year ago

    Hello, good idea and especially thank you for sharing, iown this regulator i will do it and as a bonus i will add an Arduino pin output for possibly used with 3.3V (if possible ) 5V or 9V, Thanks for sharing, cordially.


    2 years ago

    Can you add a potentiometer to the output to regulate the current?


    3 years ago

    Aren't you supposed to either (a) make a case with a very expensive laser cutter or (b) put it in an Altoids tin? We have traditions around here!

    Would be nice to see the input and output traces on a scope to see if the PSU is any good.

    4 replies

    Reply 3 years ago

    Hey hey it was only a joke. ;-) I have a 3d printer so I am only envious when I see laser cut boxes. I have a pile of Altoids tins now though.


    Reply 3 years ago

    Yes, I understand :). I haven't 3D printer, so I'll make a case from transparent plastic soon.


    3 years ago

    Nice! It's very similar to mine. I used an small etch a sketch toy as a case. I like the way you added the plugs. Interesting that yours uses buttons to adjust the voltage. Most of the ones I've seen (mine included) use a potentiometer.


    1 reply

    Reply 3 years ago

    WOW! Your design is very good. I'll put mine into a transparent box. Thanks for sharing your project! Your conception is clear and simpy good...


    Reply 3 years ago

    There is no control to limit current on that supply, it will put out whatever it can up to its limit or the limit of the input supply. You need something fancier if you want to set a max current; I saw someone here yesterday using this:


    It looks like it might have a settable limit based on the very poorly translated manual.


    3 years ago

    the problem with this kind of PSUs is, that they are very noisy. Even with commom mode choke you won't get a smooth output as you would get it from linear PSU.