5V DC POWER SUPPLY

This is a simple way to power some 5 V logic from a 240 V AC source. If a 120 V AC power adapter is used, the circuit will also work for 120 V AC power lines.

Schematic

Fig.  5 V Power Supply

Working

Here the step down transformer reduce the 240 V AC supply to 9 V AC. The main purpose of using diode is to rectify the AC supply (Converts AC to DC). Here 1 ampere diode bridge is used and it provide maximum 1 ampere of current. But the converted AC voltage into DC voltage is not pure DC voltage, it contains ripples. So to remove these ripples we need a filter. Here a 470 uF of capacitor is used. It would act as a filter and it provides smooth DC supply. In end section, 7805 voltage regulator is used. Its main purpose is to regulate the DC supply (current and voltage) according to load connected.