This circuit is a battery eliminator 1.5 V , that is, a power supply of 1.5 volts , low consumption that takes as input the output of the USB PC or notebook. The power adapter is simple , it converts the voltage from 5V to 1.5V USB ports , using the popular LM317 IC and a few other components . To be exact this circuit uses only three components , one is the LM317 , R1 = R2 = 470 ohm and 100 ohm . Eliminator 1.5 Volt battery using LM317 Circuit Diagram