Ansar's Blog

⚡Turning an old PC power supply into a fully adjustable electronics workhorse.

For the past few weeks, I’ve been hinting at a big project I’ve been working on. Well… here it is: I built my very own variable power supply.

Now, I know what you’re thinking:

• Why not just buy one?
• Isn’t that dangerous?
• Does it actually perform like a professional one?

Let’s answer those questions and I’ll show you exactly why this project was worth it — and why you might want to try it yourself.

What is a Variable Power Supply?

A variable power supply (or adjustable power supply) is a device that lets you set and adjust the output voltage and current to match your needs.

They’re essential for:

• Circuit testing
• Prototyping electronics
• Troubleshooting devices
• Educational experiments

By giving you precise, repeatable voltage and current control, they ensure your projects run exactly as intended.

In short: If you like building electronics, you need one.

Why I Built Instead of Bought

I had an old ATX computer power supply gathering dust. It already outputs 3.3V, 5V, and 12V, has its own fan, and is built like a tank.

The thought hit me:

“Why not repurpose this into a bench power supply?”

The only missing parts were:

• Banana plug to alligator clip leads
• Buck-boost converter
• Push-button switch
• High-power resistor

The beauty of the ATX PSU is that it’s safe, powerful, and ready to adapt — all you need is a bit of modification.

My Build Process (and Failures!)

I’ll be honest… I failed twice before I got it right.
Why? I initially tried to build my own DC converter instead of buying one. Cheaper? Maybe. Safer? Absolutely not.

Eventually, I ordered a buck-boost converter online — simple, cheap, and reliable. That removed a lot of risk.

For the case, I used a 3D printed design by Caelestis Workshop.

If you want the step-by-step guide, check out their excellent Instructables tutorial.

⚠ Safety note: You’re working with mains voltage inside the PSU. Do this at your own risk and only if you’re confident handling electronics.

The Finished Build

Now I have a sturdy, adjustable power source for all my future projects. The voltage can go anywhere I want, and the built-in cooling keeps everything safe.

What I’ll Use It For

Here’s where it gets exciting — this power supply will fuel some big upcoming projects:

1. Solar Tracker 🌞
   • A motorized system to follow the sun for better solar efficiency.
2. Shape Optimization Research 🌀
   • Using CFD simulations to design better wind turbine blades, drone propellers, and underwater propellers.
3. Hydrogen Production Experiments 💧⚡
   • Testing how different electrode shapes affect hydrogen output efficiency.

And that’s just the beginning.

Why You Might Want to Build One

Even if you don’t have my exact project list, a bench power supply is an electronics Swiss army knife.
With one on your desk, you can:

• Power microcontrollers
• Test LED circuits
• Drive motors
• Charge batteries
• Experiment safely with new components

Plus, building it yourself means you’ll learn more about electronics than you would by buying one ready-made.

Resources

• 3D printed enclosure by Caelestis Workshop
• Detailed Instructables guide
• Safety tip: Always discharge capacitors and unplug the PSU before working on it.

💬 Your Turn — Have you ever built your own electronics lab tool? Would you try converting an old ATX PSU into a variable supply?