> > > 1) I have a 12 volt DC supply. 12 volts seems to be > > > within the VIN range for the 7805s whose data > > > sheets I've now read. Can I simply apply 12 volts? > > > > Yes, but that regulator might get mighty hot! I would > > not do this for fear of cooking the poor thing. > > That's what I figured to start with, before reading the > datasheets.
If as your photos (in another message) suggest it will run OK from 8V with no heatsink on the 7805, then I would be pretty sure it will be OK at 12V if you bolt a reasonable heatsink to the regulator. Give it a smear of silicone grease, of course. -tony