How to distinguish the positive and negative poles of a cigarette lighter?
2 Answers
The method to distinguish the positive and negative poles of a cigarette lighter: The elastic head in the middle of the plug is the positive pole, and the clamping ears on both sides are the negative poles. The cigarette lighter is a component found in all cars, designed to provide a convenient fire source for drivers who smoke. Generally, cigarette lighters are mainly used in places where open flames are prohibited, such as factories and workshops, where smoking requires the use of a cigarette lighter. In addition to lighting cigarettes, car cigarette lighters can also be equipped with a car inverter, which converts the 12V, 24V, or 48V DC power in the car into 220V 50Hz AC power for use with ordinary electrical appliances, such as charging mobile electronic devices.
I've researched this when I was into car audio modifications. The small metal round tip in the center of the cigarette lighter socket is the positive pole, while the surrounding metal spring clips are the negative. The most accurate way is to use a multimeter: touch the red probe to the center hole and the black probe to the metal ring on the side. If it shows around 12V, then the red probe side is positive. Never reverse the polarity when connecting dash cams or air pumps, or at best you'll blow a fuse. By the way, don't exceed 10 amps for cigarette lighter power supply, which translates to about 120 watts as the safe upper limit for appliances. Long-term high-power usage can cause the plug to overheat and deform - my friend's navigation system wiring harness burned out exactly this way.
