3 step down 12v to 9v converter circuits 9v circuits battery eleccircuit Lm317 to output 3.3 volts
Lm317 diagram 3v volts output fritzing circuit if source above microcontroller
3 step down 12v to 9v converter circuits | ElecCircuit.com
LM317 to output 3.3 Volts - MicroController Electronics