Bench power supply

I got inspired by this video:

The kit can be obtained for less than 10$, so you "only" need the rest of the stuff (case, better potentiometers, voltmeter, ampermeter, connectors, switches, etc.). I have purchased my kit from aliexpress (click on the image below):

I had a broken UPS, so I could reuse its case and transformer. I also had a cooler (heat sink with a fan) from my old processor, so I got this:

Here is a different point of view:

And, finally, here is the completed project (I have connected my Raspberry Pi 3):

For voltage regulation I have replaced the original potentiometer from the kit with the precise one, with multiple turns. That way I can set very precise voltage. For current limitation, I have left the original potentiometer. This power supply has the overcurrent protection and when it happens, the LED turns on. I have connected that LED connector to the UPS built-in LED.

Conclusion

This power supply is a linear one. It means that all the voltage difference between input and output  multiplied by current gets dissipated on a large transistor with the heat sink. It is not the most efficient way of regulating power, but for couple of bucks it is a nice project.