Hi all, I took my 12v tester appart last week and basically trying to work out how it all works. Just curiouse thats all. Inside the handle part which is clear there are two LEDS one red for positive and a green one for earth testing. They seem to be wired together with a resitor one end which then is connected to earth. The other end of the circuit is connected to the tip of the tester just wondered how it was all working thats all. Can anyone help here.