- Joined Apr 16, 2010
I have built several simple power supplies using the LM7812 and schematics snagged from various sources, however the sources are very inconsistent in the values of the electrolytic capacitors both on the input and output sides of the 7812. Is there a simple calculation for these values or perhaps a reference table? Secondly, many do not use bypass capacitors on the input and outputs of the 7812 even though some datasheets recommend them; under what circumstances can/should they be omitted? And finally, how do I determine if a heat sink is required on the 7812 and what size it should be? As you can tell, I'm not an engineer, so help is appreciated; thanks in advance.