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 bi-pin base was invented by
Reginald Fessenden for the
1893 World's Fair in
Chicago
Chicago is the List of municipalities in Illinois, most populous city in the U.S. state of Illinois and in the Midwestern United States. With a population of 2,746,388, as of the 2020 United States census, 2020 census, it is the List of Unite ...
. After
Westinghouse won the
contract
A contract is an agreement that specifies certain legally enforceable rights and obligations pertaining to two or more parties. A contract typically involves consent to transfer of goods, services, money, or promise to transfer any of thos ...
to wire and illuminate the first electrified fair with
AC instead of arch-rival
Thomas Edison
Thomas Alva Edison (February11, 1847October18, 1931) was an American inventor and businessman. He developed many devices in fields such as electric power generation, mass communication, sound recording, and motion pictures. These inventions, ...
's
DC, Edison and his
General Electric
General Electric Company (GE) was an American Multinational corporation, multinational Conglomerate (company), conglomerate founded in 1892, incorporated in the New York (state), state of New York and headquartered in Boston.
Over the year ...
company refused to allow his
patent
A patent is a type of intellectual property that gives its owner the legal right to exclude others from making, using, or selling an invention for a limited period of time in exchange for publishing an sufficiency of disclosure, enabling discl ...
ed
Edison screw-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 "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