ATX VARIABLE BENCH POWER SUPPLY

INTRODUCTION

This is a common project for electronic students.
I already had many type of bench power supplies, always reusing old ATX power supplies I had around.
In this project I decided to show something different, a VARIABLE bench power supply.
The project is simple and easy to be done, with two independent power sources capable of a 5A load, enough for most projects.

PARTS

  • Used ATX power supply
  • 2 step down voltage regulators 5A with display
  • 2 Potentiometers 10k
  • 2 potentiometer knobs
  • 4 banana pin conectors

SCHEMATICS

BUILDING

As you can see at the above picture, there are only a few connections to be made, so I will focus in explaining some building details. You should read everything first before starting the project.

VOLTAGE REGULATOR PREPARATION
The voltage regulator has a mini potentiometer in it, but we will use our own potentiometer to control it. For this reason you need to first remove the original potentiometer and weld three wires that will be used at the external potentiometer. In my case, I welded three pins, to allow to connect and disconnect the wires, but this is optional.

WIRE CUTS
When you open the power supply and start the work, you will notice that there are many wires you will not use. You can cut all the wires and leave them with 5cm, except two of each color, that you can leave long.

ADAPT YOUR IDEA TO THE POWER SUPPLY SHAPE
Each power supply has its own internal and external characteristics. In my case, I decided to use the power supply´s back for several reasons. The first reason is that there was already a on/off button, that would be faced to the front. Another reason were the little holes that helped to attach things. My only work was to remove the power plug from the front, use the hole to place the potentiometers using a small piece of acrylic I had here,  e pass the enery cable through a hole in the other side.

CHECK INTERNAL SPACE
Power supplies usually have very tight space inside. Since you already passed byt the wire cut step, you will notice you earned a lot of space with that, but yet, depending on your design, the space may not be enough. In my design, what helped was to move the cooler to outside the power supply. A lot of more internal space and I think it became even more beautiful.



TEST THE PROJECT FIRST

Before start to drilling the power supply body, place things inside, make a test and connect the wires at the voltage regulators, like in the drawing, and use a multimeter to check if it is working. It will be no fun if at the end of the project you find out that used power supply you have chosen is burned.

CONCLUSION

I did not gave building details on purpose, because this would make you anxious, and when you started to work in a completely different power supply, you would try to do the same steps and would fail miserably.
The way it is, I have just shown the way to you, and you still need many creativity to make it work. In either case, this is the funny part. 🙂

If you need help just contact me.

Ricardo Andere de Mello
quilombodigital@gmail.com

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