where is the positive on a cigarette lighter
Cigarette lighter receptacle The sockets and mating plugs are defined in the ANSI/SAE J563[7] specification. For the 12 volt systems, the "contact point", which is the center part of the plug when viewed end-on, carries the positive voltage, whereas the "can" part, which is the outer part of the connector, carries the negative voltage (which is the "ground" connection for most automobiles, which have a negative ground electrical system).