BASIC POWER SUPPLY CIRCUIT DIAGRAM

In the above circuit, AC VOLTAGE is the input. It passes through the Bridge circuit and gets converted to DC VOLTAGE. Then the converted voltage is filtered by using the ELECTROLYTIC CAPACITORS to reduce the AC spikes that are present in the converted DC VOLTAGE. After filter capacitor the dc voltage needs to be regulated to get the required voltages like 12v,5v,3.3v. After regulating the voltage, LED is connected to the output for POWER indication.