Step Down Voltage

I have a 20W source that voltage can change between 5V, 9V, 12V, and 20V that I want to step down to power a PIC with 5V. What should I use to step down that type of power. Thank you!

Have you tried LM7805?

I was thinking that the power loss would be too great but realized that the PIC is only using about 60 uA which is nothing.

Hi , Robert Gauthier

If your voltage source is dc then connect the 12v dc to pin no 1 of 7805 ic also connect a 470 mfd 25v capacitor +ive lead from pin 1 of ic and the negative lead to your supply negative also connect a 0.1 50v polyster capacitor parallel to the 470 mfd cap,now connect the 2nd pin of ic to the negative of your 12v power source. now connect a 0.1 uf polyster to the 3rd pin of the ic and connect the other end of the cap to the negative, now connect a 10mfd 25v cap +ive terminal to pin 3 0f the ic and connect the negative terminal of the cap to the negative of the 12v supply now connect a 50 ohms half watt resistor to the pin no 3 of the ic.connect the other end of the resistor to the +ive supply of the pic ic circuit and the negative of the12v source to the picic circuit negative point .this power supply will supply 5v dc and the max current it can supply to your circuit will be 100 ma. this will help you , pl review my rating .


Thank you. Sambath kumar