This circuit is universal power supply , you can use this circuit to supply . On the IC you can adjustable regulator provides short circuit protection and automatic voltage adjust . The input voltage to the circuit regulator is supplyed by AC 220 V / 110 V and down voltage by transformator then rectified by bridge diode . And output voltage is clear and stabilized .
See Universal Power Spply Schematic below :
Wiring a second LM317 , U2 , in parallel with U1 is a quick and clean way to increase the current limiting threshold to 3A without sacrifing short-circuit protection.When more than 3A is required , the regulator module can be used to drive the base of one or more pass-transisotrs.