Quote Originally Posted by kevj View Post
2) Polarity protection. Assume my circuit is all complete with a voltage regulator, pic, and varous components. It's powered from a single battery cell, and I want to add reverse polartiy proection (if the user puts the batt in backward). I put a batt in backward and it seems fine but again, I'd like to add some intentional protection for this.
Assuming your circuit, regulators, etc. can handle it (i.e. drop out voltages, etc), a couple of diodes could make it so that it wouldn't really matter if a person did plug the battery in backwards...but at the same time, ground would act a bit goofy since it would be offset just a bit.