DC power supply circuit design

3volt pocket radio power supply using IC 7805 and 3 diodes.

7806, 7808, 7810 not available in Kerala.available is 7805, 7809, 7812 etc. How can get 3 volt supply from 5 v regulator ?

3x 1N4001 in series .By applying simple techniques using diodes and zeners, we can increase or decrease output voltages of regulator ics

For 15v output, use 7815 ic.if you don't get it, use 7812 ic,with 3.3 v zener diode. Zener should be connected between pin 2 and grnd in reverse bias.

Instead of 78 series you can use 79 series , which is positive às ground and negative voltage rectification

 Series diode is Increasing 0.6 volts of 5v ic , means 5.6 output, if you add one more diode in series , voltage will be 6.2 , (but these all are depends up on the type of diode, dropping of voltages may different in various types of diodes)

 The difference between 7805 and 78L05 regulator ics? Both are freely available here.

L version has lower current supply capacity. Not more than 100mA. Smaller in size also.