Power Supply circuit

7805 is a 5V fixed three terminal positive voltage regulator IC . The IC has features such as safe operating area protection, thermal shut down, internal current limiting which makes the IC very rugged.

Output currents up to 1A can be drawn from the IC provided that there is a proper heat sink. A 12V transformer steps down the main voltage, 1A bridge rectifies it and capacitor C1 filters it and 7805 regulates it to produce a steady 5V DC.