Hi All I'm working in a project well a simple pic multi-meter based on on bench power supply one I have working ok, Now I want to make a portable meter of it now this would be ok if you made sure you got the connections the correct way roun, I know I could add reverse polarity diodes but I would like to some how have it where it does not matter how you connect the leads to the input the output to the ADin pin on the pic would read say 0-2.5V if the leads wrong way round(where I could display a - sign) and 2.5-5V if they was correct way connected or same again no matter how the leads are connected I get 0-5V to the ADin pin and then can add a circuit to go high and the pic chip looks for this, Now I've tried a differnational configured op-amp but no matter if there is no leads or whcih way round they go I always get a 5v output, Now this may be the way I had it set up. What would be the best method and the correct way so no matter how you connect the leads up you get a 05V out to the ADin pin hope you can understadn what I'm trying to explain what I'm doing Thanks