The LM317 is a favorite for many people who want quick, cheap, reliable and ajustable power. It only takes a few parts to set up and it does its job rather well. Sometimes though, ...

It’s a simple, constant voltage power supply that’s variable from 0.6 V all the way up to 12 V. It’s powered through a micro USB port, and you get 3.3 V and 5 V rails automagically.