Simple step-up DC – DC converter on a single transistor
This converter works almost with any elements. I assembled with his pile of rubbish over, literally 5-10 minutes. Although current output goes low (about 30mA), but with a small strapping power will be enough for LED or microcontroller .
Its main advantage is that it works from 1.2V battery. But be careful if you give it more than 3.0V, then the circuit may fail.