- Bi-pin connector
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A metal halide lamp with a bipin cap.
A bipin or bi-pin, (sometimes referred to as 2-pin, bipin cap or bipin socket), is a standard from the IEC for lamp fittings. These are used on many small incandescent light bulbs (especially halogen lamps), and on most fluorescent lights as well, where the filaments are involved in starting the tube when it is turned on.
Some lamps have pins placed closer together, preventing them from being interchanged with bulbs that are too high power, which may cause excessive heat and possibly fire. These are sometimes called "mini-bipin". Some of these, particularly in automotive lighting, have the pins bent back onto the sides of the base of the bulb, this is instead called a wedge base or socket.
The bi-pin base was invented by Reginald Fessenden for the 1893 World's Fair in Chicago. After Westinghouse won the contract to wire and illuminate the first electrified fair with Nikola Tesla's AC instead of archrival Thomas Edison's DC, Edison and his General Electric company refused to allow his patented Edison screw-base bulbs to be used. Westinghouse overcame this by inventing the bi-pin base to use at the fair.
Contents
Codes
Type Standard Pin centre to centre Pin diameter Usage G4 IEC 60061-1 (7004-72) 4.0 mm 0.65-0.75 mm MR11 and other small halogens of 5/10/20 watt and 6/12 volt GU4 IEC 60061-1 (7004-108) 4.0 mm 0.95-1.05 mm GY4 IEC 60061-1 (7004-72A) 4.0 mm 0.65-0.75 mm GZ4 IEC 60061-1 (7004-64) 4.0 mm 0.95-1.05 mm G5 IEC 60061-1 (7004-52-5) 5 mm T4 and T5 fluorescent tubes G5.3 IEC 60061-1 (7004-73) 5.33 mm 1.47-1.65 mm G5.3-4.8 IEC 60061-1 (7004-126-1) GU5.3 IEC 60061-1 (7004-109) 5.33 mm 1.45-1.6 mm GX5.3 IEC 60061-1 (7004-73A) 5.33 mm 1.45-1.6 mm MR16 and other small halogens of 20/35/50 watt and 12/24 volt GY5.3 IEC 60061-1 (7004-73B) 5.33 mm G6.35 IEC 60061-1 (7004-59) 6.35 mm 0.95-1.05 mm GX6.35 IEC 60061-1 (7004-59) 6.35 mm 0.95-1.05 mm GY6.35 IEC 60061-1 (7004-59) 6.35 mm 1.2-1.3 mm Halogen 100W 120V GZ6.35 IEC 60061-1 (7004-59A) 6.35 mm 0.95-1.05 mm G8 8.0 mm Halogen 100W 120V GY8.6 8.6 mm Halogen 100W 120V G9 IEC 60061-1 (7004-129) 9.0 mm Halogen 120V (US) / 230V (EU) G9.5 9.5 mm 3.10-3.25 mm Common for theatre use, several variants GU10 10 mm Twist-lock 120/230-volt MR16 halogen lighting of 35/50 watt, since mid-2000s G12 12.0 mm 2.35 mm Used in theatre and single-end metal halide lamps G13 12.7 mm T8 and T12 fluorescent tubes G23 23 mm 2 mm GU24 24 mm Twist-lock for self-ballasted compact fluorescents, since 2000s G38 38 mm Mostly used for high-wattage theatre lamps GX53 53 mm Twist-lock for puck-shaped under-cabinet compact fluorescents, since 2000s 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 two diameters, being larger near the ends, in order to twist-lock into position in the socket (the transition between the two diameters is a right-angle step rather than a taper); in others, the base of the lamp has a groove which can be held by a spring or clip.[1]
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 tubes (both halogen and fluorescent) with one pin at each end, as well as high-output fluorescents with recessed or shrouded contacts, which are not covered here.
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Halogen lamps with GU4 (left) and G4 (right) bases
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Halogen lamp with G6.35 base
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Metal halide lamp with G8.5 base
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Halogen lamp with G9 looped-pin base
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Halogen lamp with GU10 twist-lock base
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LED spotlights with GU10 base
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MR16 LED lamp with GU5.3 base
See also
- Bayonet mount
- Wedge base
References
External links
Categories:- Lamps
- Electrical connectors
- Mechanical standards
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