When it comes to necessary lab equipment, a lab-bench power supply is a must. I managed to get through the early days of my hobby by using salvaged wall-warts with fixed voltages and fixed current limits. But when it came to testing my new LED panel for the V-I curve, I found it really cumbersome to connect two multi-meters to a PSU, then adjust the voltage trim and record the data. That’s why I decided to build this small project.
The main crux of this project was the 3D printed case and knobs, which had to be modeled and printed on my Anet A8 printer. I used AutoDesk Fusion 360, which seems like a more 3D-printer friendly version of the Inventor software. I made sure to include small details, like structural filets on the corners, and standoffs for the main buck-converter module.
The internal circuit is really simple and inexpensive. It consists of mainly a DC-DC converter module, an ammeter, voltmeter, a button, and a pair of potentiometers. I had to replace the “trim” style potentiomers on the board with larger 10-turn variants, and also re-locate the current-limit indicator LED to the outside of the enclosure. I would rate this power supply at 0-30V 5A. The main limitations are the small-gauge wires which puts an upper limit on the current, and the maximum voltage input for the displays being at 30V.
This small project was more functional than an exersise in building something new. Regardless, it should serve me well, and the current limit should save me from burning a project or two. Here’s some more photos: