1st when the A.C. is supplied to the transformer, it steps down the 230V main supply to 6 volts. It has a capability of delivering a current of 500mA. The 6 volts A.C. appearing across the secondary is the RMS value and the peak value is 8.4 volts. During the 1st half cycle of the A.C. input Diode D1 is forward biased and a current ‘I’ flows in the circuit in the direction S 1D1 ABEOS1. During this time diode D2 is reverse biased. So, it does not conduct any electric current. During the next half cycle, the diodeD2 is forward and D1 is reversed. Hence D2 conducts current in the direction S2D2 ABEOS2and D1 does not conduct any current. In subsequent half cycles of the A.C current the above processes are repeated.

In both the half cycles it is clear that current flows through the resistor in only one direction ABE. Even though the voltage across RL is unidirectional it will still contain a few A.C components. This is filtered and made smooth using a capacitor, which filters 99% of the A.C current. A resistor is then used to adjust the output voltage. Capacitor also nearly filters all A.C components from the supply and resistance is adjusted for the required output. As this is a simple circuit, only one capacitor and a resistance are being used. But there will be slight factor of A.C. current still left in the output but it is negligible. The output Direct Current and voltage light up the LED.