History and Development of Edison Screw
– Early manufacturers of incandescent lamps used different bases in the 1880s and 1890s.
– Edison designed his screw based on the lid of a kerosene can.
– Thomson-Houston Electric Company used a threaded stud and a flat contact ring.
– Sawyer-Man or Westinghouse base used a spring clip and a contact stud.
– Smaller competitors had to produce lamps for all three types.
– Proposals for international standards for Edison screws began in 1918.
– All attempts to reach consensus by 1925 failed, but lamp makers continued the work independently.
– Two standards were developed—one for Europe and another for the Americas—which were endorsed by the IEC in 1930 and 1931.
– E-designations of screws originated in Germany and were adopted by the IEC.
– The standards harmonize the two major screw mount types.
Types and Sizes of Edison Screw
– Lamp mount types are defined in ANSI and IEC publications.
– The designation Exx indicates the diameter in millimeters of the thread on the base.
– There are four commonly used thread size groups for mains supply lamps: Candelabra, Intermediate, Medium or standard, and Mogul.
– E26 and E27 bases are usually interchangeable, as are E39 and E40.
– Other semi-standard screw thread sizes are available for specific applications.
– 7004-26: HTS with a diameter of 18mm (0.709in)
– E18: Edison Screw with a diameter of 18mm (0.709in)
– 3.0: Standard 120V lamps using E26 with a diameter of 26mm (1.024in)
– E26: Medium one-inch Edison Screw (ES) with a diameter of 26mm (1.024in)
– 7004-21A-2: Standard 230V lamps using E27 with a diameter of 27mm (1.063in)
– 3.62: Medium Edison Screw (ES) with a diameter of 27mm (1.063in)
– E39: Single-contact (Mogul in America) Goliath Edison Screw (GES) with a diameter of 39mm (1.535in)
– 120V 250+W industrial lamps use E39
– 7004-24A-1: 230V 250+W industrial lamps use E40 with a diameter of 40mm (1.575in)
– Three-way lamps have double contacts, usually E26d or E27d, or rarely E39d
Fittings and Applications of Edison Screw
– Different designations and base diameters are used for various types of bulbs.
– E5 (E5.5) is used for indicator lights and decorative lights.
– E10 is used for flashlights and bicycle lights.
– E11 is used for 120V halogen mini-candelabra.
– E12 is used for 120V candelabra/night lamp.
– E39 and E40 bases are used for street lights, high-wattage lamps, and high-intensity discharge lamps.
– Medium Edison screw (MES) bulbs for 12V are produced for recreational vehicles.
– Intermediate bases are used for large outdoor Christmas lights, desk lamps, and microwave ovens.
– E27 and E14 are the most common screw-mount sizes in countries with 220-240 Volt AC power.
– E12 is typically used for candelabra fixtures, while E14 or E17 are used in small table lamps and novelty lighting.
Other Uses and Related Concepts of Edison Screw
– Edison screw socket used as an outlet in the past.
– Edison base fuses used in buildings wired before 1960.
– Adapters for wall outlets use Edison screw for various purposes.
– Accessories like smoke detectors and flashers designed for Edison screw base.
– Some vacuum tubes, such as certain rectifiers, use Edison screw base.
– A-series light bulb.
– Multifaceted reflector.
– Screw thread diameters.
– GU24 lamp fitting.
– BC or bayonet mount fitting used in the UK and some other countries.
Regulations and Resources Related to Edison Screw
– The 2007 Energy Bill introduced regulations to phase out incandescent bulbs.
– Some countries have banned or restricted the sale of incandescent bulbs.
– However, there are exemptions in place for specific applications.
– The phasing out of incandescent bulbs aims to promote energy efficiency.
– The transition to more energy-efficient lighting options has been encouraged.
– Bailey – The lamp company is an example of a company involved in Edison screw production.
– BulbTown is a resource that provides information on Edison screw bulbs.
– The IEC (International Electrotechnical Commission) sets standards for lamp caps and holders.
– The book ‘Beyond Fear: Thinking sensibly about security in an uncertain world’ by Bruce Schneier includes information on Edison screws.
– The Thomas A. Edison, Inc. company has a historical connection to the invention of the Edison screw. Source: https://en.wikipedia.org/wiki/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 metal bases (caps) which screw into matching threaded sockets (lamp holders). For bulbs powered by AC current, the thread is generally connected to neutral and the contact on the bottom tip of the base is connected to the "live" phase.
In North America and continental Europe, Edison screws displaced other socket types for general lighting. In the early days of electrification, Edison screws were the only standard connector, and appliances other than light bulbs were connected to AC power via lamp sockets. Today Edison screw sockets comply with international standards.
Their types are designated as "Exx", such as "E26", where "xx" indicates the diameter of the socket in millimeters.
