An automobile auxiliary power outlet (also known as car outlet, automotive power socket, automobile outlet, vehicular outlet, and similar; formerly known as a cigarette lighter receptacle, cigar lighter receptacle or cigar lighter socket) in an automobile was initially designed to power an electrically heated cigarette lighter, but became a de facto standard DC connector to supply electrical power for portable accessories used in or near an automobile, directly from the vehicle's electrical system.
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In most vehicles, at least one car outlet is present. Some vehicles, especially vans, tend to have more power outlets, usually one for the front passengers, one for the rear passengers and one for the luggage trunk.
The voltage of the power outlet is usually near 12 V DC, (14V to 15V while the running engine is turning the alternator, in order to charge the car battery while providing electrical power), because it is directly powered without regulation from the car's electrical system.
Lighter
The lighter is a metal or plastic cylinder containing a thin flat coil of nichrome metal strip, through which high current (≈10 amperes) passes when the device is activated, usually by pushing it into the socket as though it were a push-button. When pushed in, the lighter is held against the force of a spring by a clip attached to a bi-metallic strip. The heating element glows orange hot in seconds, causing the bi-metallic strip to bend and release the mechanism, and the handle pops out, eliminating the need for the user to time the heating operation. If the lighter is then promptly removed from its socket, it can light a cigarette, cigar, or tinder.
Electrical Outlet
In newer cars, the socket is equipped with a plastic cover without the lighter heating element. However, the socket has been repurposed and continues to be used to power consumer electronics in vehicles. Often, a vehicle may come with several outlets for convenience, some in the rear passenger area of the vehicle or even the cargo area, for powering portable devices. These outlets usually have a plastic cap tethered to them, and are usually labeled as being only for DC power, because they are not intended to withstand the heat produced by an electrical cigarette lighter.
Technical Details
The sockets and mating plugs are defined in the ANSI/SAE J563 specification. For the 12 volt systems, the center contact is the positive terminal and the shell is the negative terminal. Most automobiles connect the negative terminal to the frame of the vehicle (negative ground).
12 volt auto connectors are made to comply with a standard by Underwriters Laboratories for safety. UL2089 was developed to cover the requirements for portable adapters rated 24 V DC or less that are intended to be supplied from the battery powered electrical system of a vehicle. Products covered by the standard include cord assemblies of a plug that mates with the standard cigarette receptacle found in automobiles.
- 6-volt cigarette lighter receptacle and plug
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Receptacle inside diameter: 21.34–21.46 mm (median 21.4 mm)
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Plug body diameter: 21.08–21.23 mm (median 21.155 mm)
- 12-volt cigarette lighter receptacle and plug, size A
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Receptacle inside diameter: 20.93–21.01 mm (median 20.97 mm)
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Plug body diameter: 20.73–20.88 mm (median 20.805 mm)
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Most often used in American automobiles
- 12-volt cigarette lighter receptacle and plug, size B
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Receptacle inside diameter: 21.41–21.51 mm (median 21.455 mm)
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Plug body diameter: 21.13–21.33 mm (median 21.18 mm)
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Most often used in European automobiles, and sometimes as a second socket in American automobiles expressly for DC power connections.
Plugs often include a pilot light LED indicator to indicate that electrical power is connected. Optionally, the plug may be equipped with an internal fuse for electrical safety, usually rated at 10 amps or less. In some designs, the tip of the plug may be unscrewed to reveal a cylindrical glass fuse; other variants may use a blade-type fuse inserted into the side or back of the plug.
