I have a logic level circuit that I need to run of a car's electrical system that can vary from 11v to 14v. What's the simplest way to provide a regulated 5v source?
Mouser is a good place to look for that part, only catch is shipping is flat rate by weight and you'll pay 24 cents for the part and then 8 bucks to have it delivered. If you can find one without outrageous shipping, that'd be better for you.
I don't know the current draw. It's a pwm circuit with a 556 and a 339 that drive a LL MOSFET.
I'm just north of Atlanta GA and I have a 7805 from Radioshack in hand. Do I hook it straight up or should a put caps between the pins? There's a Fry's local to me and a commerical/industrial electronics supply store a little further away (acksupply.com).
The caps are also at RS. Other than that, you're good to go with that part up to an amp, though you may need to heat sink it (if you go over 50ma). You'll know if this is the case, just don't burn yourself.
Low dropout regulators are made for cars. They have reverse-polarity protection (sometimes a mechanic connects a new battery backwards) and high voltage input protection. I use the LM2931-5.0.