Introduction: Build Variable Bench Power Supply (500W) for Only $17

A variable power supply is one of the most important tools that a maker should own. However, a power supply like this can cost you hundreds and I'm going to teach you how to create one for less than $17. This variable power supply can give out a maximum of 500W of power in total. It contains two parts. The first part is variable (you can change the voltage and current), which can output 0.8V to 28.4V with 12A. The second part is 12V with 46A.



500w 12v or 24v power supply - $4 (I got a used one, if you cant find a used one, you can still buy a new one for only $19.

ltc3780 dc adjustable converter - $10

Digital Voltmeter Ammeter Display - $2

DC Fan - $1


Spade connecter


Piece of wood with holes on it (optional)

Paint stick (optional)


Soldering iron

Glue gun

Wire cutter and stripper


Exacto knife


Step 1: Cut Out Wood and Cardboard

Measure and cut out a piece of wood that is able to put all your components in it. I cut out 5"(12.7cm) by 13"(33cm) (you can use cardboard instead if you don't have a wooden board.)

Measure and cut 4 pieces of cardboard. Two-piece is 13"(33cm) by 3"(7.62cm) and two-piece of 4"(10.16cm) by 3"(7.62cm).

Please cut it carefully and use a cardboard that looks good so your variable power supply will look better and be more durable.

Cut some holes on your base(wooden board) to have good airflow.

Paint your board if you want.

Step 2: Test Out Power Supply Pins

I got a used power supply and I don't know which pin is for what, so I use a voltage meter to test out the pins. Your can skip this step if you already know the usage of your pins.

Step 3: Attach All Components

As denoted by the diagram above, attach all the components and solder them firmly with a soldering iron. Then cover the connection with a heat shrinking tube or electrical tape so it won't get shorted.

Step 4: Glue Paint Sticks

Cut one paint stick to get two pieces with each length is same as the width of the base (the wooden board). Glue the two-piece of paint sticks on the bottom of the base (the wooden board). Get other two paint sticks and glue them on the inside panel of the two long pieces of cardboard so it will be more durable.

Step 5: Cut Holes

Cut a hole at the place you want to put a fan.

Cut 4 holes at the place you want your output pin to be.

Cut a hole where you want your voltage meter to be.

Cut a hole where you want your adjusting button will be.

Step 6: Put Them All Together

Use hot-glue to glue fan, output pin, power supply, walls, voltage meter and Ltc 3780 at where you want it to go.

Lastly glue the wall, top, front and back on the base(the wooden board). Only glue a few dots of glue for the top panel so you can take it apart easily.

Step 7: Done & Test

BOOM! You are done! You can test out your power supply to check if is working or not. You can also add a button to control the fan like what I did, so you can turn off the fan when you are not using it.

If you like my tutorial please give me a vote on the contest and thank you very much for watching.

If you have any questions or improvements I can make, please comment below. By the way, I'm only 13 years old.

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