- 220V/110V mains-powered
- continuously adjustable output voltage
- isolated output
- nice acrylic case
- built-in LED voltmeter
The kit and PCB comes with a few "valued-added features" unrelated to the power supply function (CD4069 square-wave generator, externally-triggered piezo buzzer, externally-triggered polarity tester), but I decided to leave those out of the build.
I also enjoyed investigating and old-school transformer-based power supply. These are getting rare .. it's hard to even find a 220/12 transformer for less than the price of the kit these days, and then they are mostly used/refurbished.
How does it perform? Nice! No smoke on power-up, but a few things to note and/or improve. And I'm sure it wouldn't pass a safety certification, so don't go building one like this for friends.
As always, all notes, schematics and code are in the Little Arduino Projects repo on GitHub.