A bipin or bi-pin (sometimes referred to as two-pin, bipin cap or bipin socket) is a type of
lamp fitting. They are included in the
IEC standard "IEC 60061 Lamp caps and holders together with gauges for the control of interchangeability and safety". They are used on many small
incandescent light bulbs (especially
halogen lamps), and for starters on some types of
fluorescent lights.
Some sockets have pins placed closer together, preventing the low-power bulbs they use from being replaced by bulbs that are too high
power, which may generate excessive heat and possibly cause a fire. These are sometimes called "mini-bipin". Where the terminals of the lamp are bent back onto the sides of the base of the bulb, this forms a
wedge base, often used in small bulbs for
automotive lighting
The lighting system of a motor vehicle consists of lighting and signalling devices mounted to or integrated into the front, rear, sides, and in some cases the top of a motor vehicle. They illuminate the road ahead for the driver and increase t ...
.
The bi-pin base was invented by
Reginald Fessenden for the
1893 World's Fair
The World's Columbian Exposition (also known as the Chicago World's Fair) was a world's fair held in Chicago in 1893 to celebrate the 400th anniversary of Christopher Columbus's arrival in the New World in 1492. The centerpiece of the Fair, hel ...
in
Chicago. After
Westinghouse won the
contract to wire and illuminate the first electrified fair with
AC instead of arch-rival
Thomas Edison's
DC, Edison and his
General Electric company refused to allow his
patented
Edison screw
Edison screw (ES) is a standard lightbulb socket for electric light bulbs. It was developed by Thomas Edison (1847–1931), patented in 1881, and was licensed in 1909 under General Electric's Mazda trademark. The bulbs have right-hand threaded ...
-base bulbs to be used. Westinghouse overcame this by developing the bi-pin base for use at the fair. An incandescent electric lamp with a bi-pin base was patented by the Westinghouse (G. Westinghouse, Jr.) in 1895.
Types
The suffix after the G indicates the pin spread; the G dates to the use of Glass for the original bulbs. GU usually also indicates that the lamp provides a mechanism for physical support by the
luminaire: in some cases, each pin has a short section of larger diameter at the end (sometimes described as a "peg" rather than a "pin"); the socket allows the bulb to lock into place by
twisting it; in others, the base of the lamp has a groove which can be held by a spring or clip.
A
lowercase
Letter case is the distinction between the Letter (alphabet), letters that are in larger uppercase or capitals (or more formally ''majuscule'') and smaller lowercase (or more formally ''minuscule'') in the written representation of certain lang ...
"q" at the end of the designation indicates that it is a quad-pin base, with two bi-pin pairs. These are used with
compact fluorescent tubes that plug into a
light fixture that has a permanent ballast.
There are also double-ended halogen and fluorescent tubes with one pin at each end, and high-output fluorescents with recessed or shrouded contacts, which are not covered here.
File:Lampg4.jpg, Halogen lamps with GU4 (left) and G4 (right) bases
File:Lamp6-35.jpg, Halogen lamp with G6.35 base
File:Halogenmetalldampflampe.jpg, Metal halide lamp with G8.5 base
File:Lampg9.jpg, Halogen lamp with G9 looped-pin base
File:Lampgu10.jpg, Halogen lamp with GU10 twist-lock base
See also
*
Bayonet mount
*
Fluorescent-lamp formats
*
Fluorescent lamp
*
Multifaceted reflector (MR)
References
External links
*
Cross-reference for EU/US
{{DEFAULTSORT:Bi-Pin Connector
Types of lamp
Electrical power connectors
Mechanical standards