Driving a 7805 or how else to get +5VDC reg (was Re: My first good find!!!)

Ethan Dicks wrote: You don't have to build one. They are available as sealed "modules" with pins for gazinta and gazouta; very easy to use. An added advantage, when you're running off battery power, is very high efficiency for maximum operating time off your batteries. Just be sure to figure out what your battery is putting out when it's just about to be exhausted, and try to get a converter that can operate on this input voltage to get all the capacity out. Check out Jameco, Digi-Key's website to see if there's anything that fits the bill. I have a huge bin full of the venerable old 7805s. They work and they're simple, but they're also terribly inefficient and tend to run quite hot unless extensively heat-sinked, especially towards the upper end of the voltage input range and/or close to rated current flowing to the 5 volt load. I fondly remember a home-made KIM-1 power supply made with a 7812 and 7805. Despite a relatively huge heat-sinking area, the damn thing was running nearly hot enough to cause burns. I think the input voltage was around 8-10 volts somewhere. After the "MacDonald's Coffee-in-Lap" lawsuit, I wonder if I coulda sued TI for burning my fingers. ;) -- Ross