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Encyclopedia > Incandescent light bulb

The incandescent light bulb or incandescent lamp is a source of artificial light that works by incandescence, (a general term for heat-driven light emissions which includes the simple case of black body radiation). An electrical current passes through a thin filament, heating it until it produces light. The enclosing glass bulb prevents the oxygen in air from reaching the hot filament, which otherwise would be destroyed rapidly by oxidation. For other uses, see Light (disambiguation). ... Molten glassy material glows orange with incandescence in a vitrification experiment. ... As the temperature decreases, the peak of the black body radiation curve moves to lower intensities and longer wavelengths. ... In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ... An electrical filament is a thread of metal, usually tungsten, which is used to convert electricity into light in incandescent light bulbs (as developed in 1878 by Joseph Wilson Swan, among others), and into heat in vacuum tube devices. ... This article is about the chemical element and its most stable form, or dioxygen. ...


Incandescent bulbs are sometimes called electric lamps, a term originally applied to the original arc lamps. They are also known as globes or light globes with the theater, television and film industries, and both these terms are commonly used in Australia. 15 kW Xenon short-arc lamp. ... For other usages see Theatre (disambiguation) Theater (American English) or Theatre (British English and widespread usage among theatre professionals in the US) is that branch of the performing arts concerned with acting out stories in front of an audience using combinations of speech, gesture, music, dance, sound and spectacle — indeed... This article is about motion pictures. ...


Incandescent bulbs are made in a wide range of sizes and voltages, from 1.5 volts to about 300 volts. They require no external regulating equipment and have a low manufacturing cost, and work well on either alternating current or direct current. As a result the incandescent lamp is widely used in household and commercial lighting, for portable lighting, such as table lamps, some car headlamps and electric flashlights, and for decorative and advertising lighting. International safety symbol Caution, risk of electric shock (ISO 3864), colloquially known as high voltage symbol. ... This article does not cite any references or sources. ... For the Parliament song, see Flash Light (song). ...


Some applications of the incandescent bulb make use of the heat generated, such as incubators (for hatching eggs), brooding boxes for young poultry, heat lights for reptile tanks, infrared heating for industrial heating and drying processes, and the Easy-Bake Oven toy. In cold weather the heat shed by incandescent lamps contributes to building heating, but in hot climates lamp losses increase the energy used by air conditioning systems. Look up Incubation in Wiktionary, the free dictionary. ... Ducks amongst other poultry The Poultry-dealer, after Cesare Vecellio Poultry is the category of domesticated birds kept for meat, eggs, and feathers. ... A terrarium is a clear container (often plastic or glass) used to grow plants and to examine or hold small creatures. ... An infrared heater is a body with a higher temperature which transfers energy to a body with a lower temperature through electromagnetic radiation. ... The Easy-Bake Oven, currently a product of Hasbro, is a working toy oven that uses an ordinary light bulb as a heat source. ... Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ...


Incandescent light bulbs are gradually being replaced in many applications by (compact) fluorescent lights, high-intensity discharge lamps, LEDs, and other devices, which give more visible light for the same amount of electrical energy input. Some jurisdictions are attempting to ban the use of incandescent lightbulbs in favour of more energy-efficient lighting. Low-energy light-bulb redirects here. ... A compact fluorescent lamp A fluorescent lamp is a type of electric lamp that excites argon and mercury vapor to create luminescence. ... 15 kW Xenon short-arc lamp used in IMAX projectors High-intensity discharge (HID) lamps include these types of electrical lamps: mercury vapor, metal halide (also HQI), high-pressure sodium (Son), low-pressure sodium (Sox) and less common, xenon short-arc lamps. ... External links LEd Category: TeX ...

Contents

History of the light bulb

Original carbon-filament bulb from Thomas Edison
Original carbon-filament bulb from Thomas Edison

In addressing the question "Who invented the incandescent lamp?" historians Robert Friedel and Paul Israel [1] list 22 inventors of incandescent lamps prior to Swan and Edison. They conclude that Edison's version was able to outstrip the others because of a combination of factors: an effective incandescent material, a higher vacuum than others were able to achieve and a high resistance lamp that made power distribution from a centralized source economically viable. Another historian, Thomas Hughes, has attributed Edison's success to the fact that he invented an entire, integrated system of electric lighting. "The lamp was a small component in his system of electric lighting, and no more critical to its effective functioning than the Edison Jumbo generator, the Edison main and feeder, and the parallel-distribution system. Other inventors with generators and incandescent lamps, and with comparable ingenuity and excellence, have long been forgotten because their creators did not preside over their introduction in a system of lighting."[2][3] Edison redirects here. ...

Early evolution of the light bulb

[4]

Early pre-commercial research

In 1802 Humphry Davy had what was then the most powerful battery in the world at the Royal Institution of Great Britain. In that year, he created the first incandescent light by passing the current through a thin strip of platinum, chosen because the metal had an extremely high melting point. It was not bright enough nor did it last long enough to be practical, but it was the precedent behind the efforts of scores of experimenters over the next 75 years until Thomas Edison's creation of the first practical incandescent lamp in 1879.[5] In 1809, Davy created the first arc lamp by making a small but blinding electrical connection between two charcoal rods connected to a 2000 cell battery. Demonstrated to the Royal Institution in 1810, the invention came to be known as the Arc lamp. Sir Humphry Davy, 1st Baronet FRS (17 December 1778 – 29 May 1829) was a British chemist and physicist. ... For other uses, see Battery. ... The Royal Institution of Great Britain was set up in 1799 by the leading British scientists of the age, including Henry Cavendish and its first president George Finch, the 9th Earl of Winchilsea, for diffusing the knowledge, and facilitating the general introduction, of useful mechanical inventions and improvements; and for... Edison redirects here. ... 15 kW Xenon short-arc lamp. ... Charcoal is the blackish residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. ... 15 kW Xenon short-arc lamp. ...


In 1835, James Lindsay demonstrated a constant electric light at a public meeting in Dundee, Scotland. He stated that he could "read a book at a distance of one and a half feet". However, having perfected the device to his own satisfaction, he turned to the problem of wireless telegraphy and did not develop the electric light any further. His claims are not well documented. James Lindsay, (March 3, 1988-). Currently residing at Bryanston School, Dorset. ... Wireless telegraphy is the practice of remote writing (see telegraphy) without the wires normally involved in an electrical telegraph. ...


In 1840, British scientist Warren de la Rue enclosed a platinum coil in a vacuum tube and passed an electric current through it. The design was based on the concept that the high melting point of platinum would allow it to operate at high temperatures and that the evacuated chamber would contain fewer gas molecules to react with the platinum, improving its longevity. Although an efficient design, the cost of the platinum made it impractical for commercial use.[6] [7] Warren De la Rue (18 January 1815 - 19 April 1889) was a British astronomer and chemist, most famous for his pioneering work in astronomical photography. ... A coil is a series of loops. ... Look up Vacuum in Wiktionary, the free dictionary. ... The article on electrical energy is located elsewhere. ... The melting point of a solid is the temperature range at which it changes state from solid to liquid. ...


In 1841, Frederick de Moleyns of England was granted the first patent for an incandescent lamp, with a design using powdered charcoal heated between two platinum wires contained within a vacuum bulb. Charcoal is the blackish residue consisting of impure carbon obtained by removing water and other volatile constituents from animal and vegetation substances. ...


In 1845, American John W. Starr acquired a patent for his incandescent light bulb involving the use of carbon filaments.[8] He died shortly after obtaining the patent. Aside from the information contained in the patent itself, little else is known about him.


In 1851, Jean Eugène Robert-Houdin publicly demonstrated incandescent light bulbs on his estate in Blois, France. His light bulbs are on permanent display in the museum of the Chateau of Blois. Jean Eugène Robert-Houdin (Zhean Yuzhean Ro-bayr oo-da) (December 6, 1805 - June 13, 1871) was a French magician. ...


In 1872 A. N. Lodygin invented an incandescent light bulb. In 1874 he obtained a patent for his invention. Alexander Nikolayevich Lodygin Alexander Nikolayevich Lodygin (1847 – 1923) (Александр Николаевич Лодыгин in Russian) was a Russian electrical engineer and inventor, one of inventors of the Incandescent light bulb. ...


In a suit filed by rivals seeking to get around Edison's lightbulb patent, German-American inventor Heinrich Göbel claimed he developed the first light bulb in 1854: a carbonized bamboo filament, in a vacuum bottle to prevent oxidation, and that in the following five years he developed what many call the first practical light bulb. Lewis Latimer demonstrated the bulbs Göbel had purportedly built in the 1850s had actually been built much later, and found the glassblower who had constructed the fraudulent exhibits.[9] In a patent interference suit in 1893, the judge ruled Göbel's claim "extremely improbable." Heinrich Göbel, or later: Henry Goebel (April 20, 1818 - December 4, 1893), born in Germany, was a precision mechanic and inventor, an early pioneer who did much work on developing the light bulb. ... For other uses, see Bamboo (disambiguation). ... Lewis Howard Latimer (September 4, 1848 - December 11, 1928) was an African American inventor. ...

Carbon filament lamp (E27 socket, 220 volts, approx. 30 watts, left side: running with 100 volts
Carbon filament lamp (E27 socket, 220 volts, approx. 30 watts, left side: running with 100 volts

Image File history File links Size of this preview: 696 × 600 pixelsFull resolution (1061 × 914 pixel, file size: 92 KB, MIME type: image/jpeg) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Incandescent light bulb ... Image File history File links Size of this preview: 696 × 600 pixelsFull resolution (1061 × 914 pixel, file size: 92 KB, MIME type: image/jpeg) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Incandescent light bulb ...

Commercialization

Joseph Wilson Swan (1828–1914) was an English physicist and chemist. In 1850 he began working with carbonized paper filaments in an evacuated glass bulb. By 1860 he was able to demonstrate a working device but the lack of a good vacuum and an adequate supply of electricity resulted in a short lifetime for the bulb and an inefficient source of light. By the mid-1870s better pumps became available, and Swan returned to his experiments. With the help of Charles Stearn, an expert on vacuum pumps, Swan developed a method of processing that avoided the early bulb blackening in 1878. This received a British Patent No 8 in 1880.[10] On 18th December 1878 a lamp using a slender carbon rod was shown at a meeting of the Newcastle Chemical Society, and Swan gave a working demonstration at their meeting on 17th January 1879. It was also shown to 700 who attended a meeting of the Literary and Philosophical Society of Newcastle on 3rd February 1879. These lamps used a carbon rod from an arc lamp rather than a slender filament. Thus they had low resistance and required very large conductors to supply the necessary current, so they were not commercially practical, although they did furnish a demonstration of the possibilities of incandescent lighting with relatively high vacuum, a carbon conductor, and platinum lead-in wires. Besides requiring too much current for a central station electric system to be practical, they had a very short lifetime.[11] Swan turned his attention to producing a better carbon filament and the means of attaching its ends. He devised a method of treating cotton to produce 'parchmentised thread' and obtained British Patent 4933 in 1880.[12] From this year he began installing light bulbs in homes and landmarks in England, and in the early 1880s he had started his company.[13] This article needs cleanup. ...


In North America, parallel developments were also taking place. On July 24, 1874 a Canadian patent was filed for the Woodward and Evans Light by a Toronto medical electrician named Henry Woodward and a colleague Mathew Evans. They built their lamps with different sizes and shapes of carbon rods held between electrodes in glass cylinders filled with nitrogen. Woodward and Evans attempted to commercialize their lamp, but were unsuccessful. They ended up selling their patent (U.S. Patent 0,181,613 ) to Thomas Edison in 1879 [3]. is the 205th day of the year (206th in leap years) in the Gregorian calendar. ... Year 1874 (MDCCCLXXIV) was a common year starting on Thursday (link with display the full calendar) of the Gregorian calendar (or a common year starting on Saturday of the 12-day slower Julian calendar). ... For other uses, see Patent (disambiguation). ... Canadian Patent application Henry Woodward was an early pioneer in the development of the incandescent lamp. ... A portion of the 1874 actual patent application. ... For other uses, see Carbon (disambiguation). ... Alternative meanings: There is also an Electric-type Pokémon named Electrode. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ...


Thomas Edison began serious research into developing a practical incandescent lamp in 1878. Edison filed his first patent application for "Improvement In Electric Lights" on October 14, 1878 (U.S. Patent 0,214,636 ). After many experiments with platinum and other metal filaments, Edison returned to a carbon filament. The first successful test was on October 22, 1879;[14] and lasted 13.5 hours. Edison continued to improve this design and by Nov 4, 1879, filed for a U.S. patent (granted as U.S. Patent 0,223,898  on Jan 27, 1880) for an electric lamp using "a carbon filament or strip coiled and connected ... to platina contact wires."[15] Although the patent described several ways of creating the carbon filament including using "cotton and linen thread, wood splints, papers coiled in various ways,"[15] it was not until several months after the patent was granted that Edison and his team discovered that a carbonized bamboo filament could last over 1200 hours. Edison redirects here. ... For other uses, see Carbon (disambiguation). ... is the 295th day of the year (296th in leap years) in the Gregorian calendar. ... Year 1879 (MDCCCLXXIX) was a common year starting on Wednesday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Monday of the 12-day slower Julian calendar). ...


Hiram S. Maxim started a lightbulb company in 1878 to exploit his patents and those of William Sawyer. His United States Electric Lighting Company was the second company to sell practical incandescent electric lamps, after Edison. They made their first commercial installation of incandescent lamps at the Mercantile Safe Deposit Company in New York City in the fall of 1880, about six months after the Edison incandescent lamps had been installed on the steamer Columbia. Maxim in October 1880 patented a method of coating carbon filaments with hydrocarbons to extend their life. Lewis Latimer, his employee at the time, developed an improved method of heat treating them which reduced breakage and allowed them to be molded into novel shapes, such as the characteristic "M" shape of Maxim filaments. On January 17, 1882, Latimer received a patent for the "Process of Manufacturing Carbons", an improved method for the production of light bulb filaments which was purchased by the United States Electric Light Company. Latimer patented other improvements such as a better way of attaching filaments to their wire supports.[9] Hiram S. Maxim Sir Hiram Stevens Maxim (February 4, 1840 - November 24, 1916) was the inventor of the Maxim Gun in 1884, the first portable, fully automatic machine gun. ... Lewis Howard Latimer (September 4, 1848 - December 11, 1928) was an African American inventor. ...


In Britain, the Edison and Swan companies merged into the Edison and Swan United Electric Company (later known as Ediswan, which was ultimately incorporated into Thorn Lighting Ltd). Edison was initially against this combination, but after Swan sued him and won, Edison was eventually forced to cooperate, and the merger was made. Eventually, Edison acquired all of Swan's interest in the company. Swan sold his United States patent rights to the Brush Electric Company in June 1882. Swan later wrote that Edison had a greater claim to the light than he did, in order to protect Edison's patents from claims against them in the US. Joseph Swan Sir Joseph Wilson Swan (October 31, 1828 – May 27, 1914) was an English physicist and chemist, most famous for the development of the light bulb. ... THORN Electrical Industries Ltd. ...

U.S. Patent 0,223,898  by Thomas Edison for an improved electric lamp, January 27, 1880
U.S. Patent 0,223,898  by Thomas Edison for an improved electric lamp, January 27, 1880

The United States Patent Office gave a ruling October 8, 1883 that Edison's patents were based on the prior art of William Sawyer and were invalid. Litigation continued for a number of years. Eventually on October 6, 1889, a judge ruled that Edison's electric light improvement claim for "a filament of carbon of high resistance" was valid. Light bulb - Edison This image is in the public domain in the United States and possibly other jurisdictions. ... Light bulb - Edison This image is in the public domain in the United States and possibly other jurisdictions. ... Edison redirects here. ... is the 27th day of the year in the Gregorian calendar. ... Year 1880 (MDCCCLXXX) was a leap year starting on Thursday (link will display the full calendar) of the Gregorian calendar (or a leap year starting on Tuesday of the 12-day slower Julian calendar). ... PTO headquarters in Alexandria The United States Patent and Trademark Office (PTO or USPTO) is an agency in the United States Department of Commerce that provides patent and trademark protection to inventors and businesses for their inventions and corporate and product identification. ... is the 281st day of the year (282nd in leap years) in the Gregorian calendar. ... Year 1883 (MDCCCLXXXIII) was a common year starting on Monday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Saturday of the 12-day slower Julian calendar). ... William Sawyer (born 3 December 1712 at Richmond, Surrey; died 2 April 1761 at Richmond) was an English cricketer. ... is the 279th day of the year (280th in leap years) in the Gregorian calendar. ... Year 1889 (MDCCCLXXXIX) was a common year starting on Tuesday (link will display the full calendar) of the Gregorian calendar (or a common year starting on Sunday of the 12-day slower Julian calendar). ...


In the 1890s, the Austrian inventor Carl Auer von Welsbach worked on metal-filament mantles, first with platinum wiring, and then osmium, and produced an operative version in 1898. Carl Auer von Welsbach ( 9 September 1858 - 8 April 1929) was an Austrian scientist and inventor who had a talent for not only discovering advances, but turning them into commercially successful products. ... General Name, Symbol, Number platinum, Pt, 78 Chemical series transition metals Group, Period, Block 10, 6, d Appearance grayish white Standard atomic weight 195. ... General Name, Symbol, Number osmium, Os, 76 Chemical series transition metals Group, Period, Block 8, 6, d Appearance silvery, blue cast Standard atomic weight 190. ...


In 1897, German physicist and chemist Walther Nernst developed the Nernst lamp, a form of incandescent lamp that used a ceramic globar and did not require enclosure in a vacuum or inert gas. Twice as efficient as carbon filament lamps, Nernst lamps were briefly popular until overtaken by lamps using metal filaments. Walther Hermann Nernst (June 25, 1864 – November 18, 1941) was a German physicist who is known for his theories behind the calculation of chemical affinity as embodied in the third law of thermodynamics, for which he won the 1920 Nobel Prize in chemistry. ... Nernst lamp, complete, model B with cloche, DC-lamp 0. ... A Globar is a silicon carbide bar of 5 to 10 mm width and 20 to 50 mm length which is electrically heated up to 1800 to 3000 degrees Fahrenheit (equivalent to 982 to 1649 degrees Celsius or 1255 to 1922 Kelvin) with a downstream variable interference filter. ...


In 1903, Willis Whitnew invented a filament that would not blacken the inside of a light bulb. (Some of Edison's experiments to stop this blackening led to the invention of the electronic vacuum tube.) It was a metal-coated carbon filament. On December 13th 1904, Sándor Just and Ferenc Hanaman were granted a Hungarian patent (No. 34541) for a tungsten filament lamp, which lasted longer and gave a brighter light than the carbon filament. Tungsten filament lamps were first marketed by the Hungarian company Tungsram in 1905, so this type is often called Tungsram-bulbs in many European countries.[16] In 1906, the General Electric Company patented a method of making tungsten filaments for use in incandescent light bulbs. Sintered tungsten filaments were costly, but by 1910 William David Coolidge (1873–1975) had invented an improved method of making tungsten filaments. The tungsten filament outlasted all other types of filaments and Coolidge made the costs practical. In 1913 Irving Langmuir found that filling a lamp with inert gas instead of a vacuum resulted in twice the luminous efficacy and reduction of bulb blackening. Marvin Pipkin, an American chemist, in 1924 patented a process for frosting the inside of lamp bulbs without weakening them, and in 1947 patented a process for coating the inside of lamps with silica. In 1936 the coiled-coil filament was introduced which further improved the efficiency of lamps. [17] Surface mount electronic components Electronics is the study of the flow of charge through various materials and devices such as semiconductors, resistors, inductors, capacitors, nano-structures and vacuum tubes. ... Structure of a vacuum tube diode Structure of a vacuum tube triode In electronics, a vacuum tube, electron tube, or (outside North America) thermionic valve or just valve, is a device used to amplify, switch or modify a signal by controlling the movement of electrons in an evacuated space. ... Franjo Hanaman (Franjo Hannaman) (1878–1941) was a Croatian inventor, engineer, and chemist, who gained world recognition for inventing the worlds first applied electric light-bulb with a metal filament (tungsten) with his assistant Aleksandar Just, independently of his contemporaries. ... Tungsram is a Hungarian manufacturer of light bulbs and vacuum tubes since 1896, now a subsidiary of General Electric and used as a brand name only. ... GE redirects here. ... For other uses, see Tungsten (disambiguation). ... Sintering is a method for making objects from powder, increasing the adhesion between particles as they are heated. ... William David Coolidge (October 23, 1873–February 3, 1975) was an American physicist. ... Irving Langmuir (January 31, 1881 in Brooklyn, New York - August 16, 1957 in Woods Hole, Massachusetts) was an American chemist and physicist. ... Marvin Pipkin (Nov. ... The chemical compound silicon dioxide, also known as silica, is the oxide of silicon, chemical formula SiO2. ...


By 1964 improvements in efficiency and production of incandescent lamps had reduced the cost of providing a given quantity of light by a factor of thirty, compared with the cost at introduction of Edison's lighting system [18]


Cartels

Main article: Phoebus cartel

Between 1924 and 1939 the international market for incandescent light bulbs was controlled by the Phoebus cartel, which dictated wholesale prices and whose members controlled most of the world market for lamps. The Phoebus cartel was a cartel set up in 1924 that existed to control the manufacture and sale of light bulbs. ...


Construction

Incandescent light bulbs consist of a glass enclosure (the envelope, or bulb) which is filled with an inert gas to reduce evaporation of the filament. Inside the bulb is a filament of tungsten wire, through which an electrical current is passed. The current heats the filament to an extremely high temperature (typically 2000 K to 3300 K depending on the filament type, shape, size, and amount of current passed through). The heated filament emits light that approximates a continuous spectrum. The useful part of the emitted energy is visible light, but most energy is given off in the near-infrared wavelengths. This article is about the material. ... An inert gas is any gas that is not reactive under normal circumstances. ... An electrical filament is a thread of metal, usually tungsten, which is used to convert electricity into light in incandescent light bulbs (as developed in 1878 by Joseph Wilson Swan, among others), and into heat in vacuum tube devices. ... For other uses, see Tungsten (disambiguation). ... In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ... As the temperature decreases, the peak of the black body radiation curve moves to lower intensities and longer wavelengths. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... For other uses, see Infrared (disambiguation). ...

  1. Outline of Glass bulb
  2. Low pressure inert gas(argon, neon)
  3. Tungsten filament
  4. Contact wire (goes out of stem)
  5. Contact wire (goes into stem)
  6. Support wires
  7. Stem (Glass mount)
  8. Contact wire (goes out of stem)
  9. Cap (Sleeve)
  10. Insulation (Vitrite)
  11. Electrical contact

Incandescent light bulbs usually contain a glass mount, which supports the filament lead wires and allows the electrical contacts to run through the envelope without gas/air leaks. Many arrangements of electrical contacts are used. Large lamps may have a screw base (one or more contacts at the tip, one at the shell) or a bayonet base (one or more contacts on the base, shell used as a contact or used only as a mechanical support). Some tubular lamps have an electrical contact at either end. Miniature lamps may have a wedge base and wire contacts, and some automotive and special purpose lamps have screw terminals for connection to wires. Contacts in the lamp socket allow the electrical current to pass through the base to the filament. Power ratings range from about 0.1 watt to about 10,000 watts. Image File history File links Incandescent_light_bulb. ... For other uses, see Watt (disambiguation). ...


To improve the efficacy of the lamp, the filament usually consists of coils of fine wire, also known as a 'coiled coil'. For a 60 watt 120-volt lamp, the uncoiled length of the filament is usually 22.8 inches or 580 mm [19] and the filament diameter is 0.0018 inches (0.045 mm).


One of the problems of the standard electric light bulb is evaporation of the filament. Small variations in resistivity along the filament cause "hot spots" to form at points of higher resistivity; a variation of diameter of only 1% will cause a 25% reduction in service life [20]. The hot spots evaporate faster than the rest of the filament, increasing resistance at that point—a positive feedback which ends in the familiar tiny gap in an otherwise healthy-looking filament. Irving Langmuir found that an inert gas, instead of vacuum, would retard evaporation. General service incandescent light bulbs over about 25 watts in rating are now filled with a mixture of mostly argon and some nitrogen,[21] or krypton[22]. However, a filament breaking in a gas-filled bulb can form an electric arc, which may spread between the terminals and cause very heavy current flow; intentionally thin lead-in wires or more elaborate protection devices are therefore often used as fuses built into the light bulb. [23] More nitrogen is used in higher-voltage lamps to reduce the possibility of arcing. // Headline text POOP!! Danny Hornsby (also known as Gnome) is a measure indicating how strongly a Gnome can opposes the flow of electric current. ... Positive feedback is a mechanism by which an output is enhanced. ... Irving Langmuir (January 31, 1881 in Brooklyn, New York - August 16, 1957 in Woods Hole, Massachusetts) was an American chemist and physicist. ... General Name, symbol, number argon, Ar, 18 Chemical series noble gases Group, period, block 18, 3, p Appearance colorless Standard atomic weight 39. ... General Name, symbol, number nitrogen, N, 7 Chemical series nonmetals Group, period, block 15, 2, p Appearance colorless gas Standard atomic weight 14. ... For other uses, see Krypton (disambiguation). ... A 3000 volt electricity arc between two nails Electricity arcs between the power rail and electrical pickup shoe on a London Underground train An electric arc can melt calcium oxide An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, resulting from a current... 200 A Industrial fuse. ...


During ordinary operation, the tungsten of the filament evaporates; hotter, more-efficient filaments evaporate faster. Because of this, the lifetime of a filament lamp is a trade-off between efficiency and longevity. The trade-off is typically set to provide a lifetime of several hundred to 2000 hours for lamps used for general illumination. Theatrical, photographic, and projection lamps may have a useful life of only a few hours, trading life expectancy for high output in a compact form. Long life general service lamps have lower efficiency but are used where the cost of changing the lamp is high compared to the value of energy used.


In a conventional lamp, the evaporated tungsten eventually condenses on the inner surface of the glass envelope, darkening it. For bulbs that contain a vacuum, the darkening is uniform across the entire surface of the envelope. When a filling of inert gas is used, the evaporated tungsten is carried in the thermal convection currents of the gas, depositing preferentially on the uppermost part of the envelope and blackening just that portion of the envelope.


An incandescent lamp which gives 93% or less of its initial light output at 75% of its rated life is regarded as unsatisfactory, when tested according to IEC Publication 60064. Light loss is due to filament evaporation and bulb blackening. [24])


Filament notching describes another phenomenon that limits the life of lamps. Lamps operated on direct current develop random stair-step irregularities on the filament surface, reducing the cross section and further increasing heat and evaporation of tungsten at these points. In small lamps operated on direct current, lifespan may be cut in half compared to AC operation. Different alloys of tungsten and rhenium can be used to counteract the effect. [25] [26] General Name, Symbol, Number rhenium, Re, 75 Chemical series transition metals Group, Period, Block 7, 6, d Appearance grayish white Standard atomic weight 186. ...


A very small amount of water vapor can significantly affect lamp darkening. Water vapor dissociates into hydrogen and oxygen at the hot filament. The oxygen attacks the tungsten metal, and the resulting tungsten oxide particles travel to cooler parts of the lamp. Hydrogen from water vapor reduces the oxide, reforming water vapor and continuing this water cycle. The equivalent of a drop of water distributed over 500,000 lamps will significantly increase darkening. [27]


In a halogen lamp uneven evaporation of the filament and darkening of the envelope is reduced by filling the lamp with a halogen gas at low pressure. These lamps can operate at a higher filament temperature without unacceptable loss of life, giving them a higher luminous efficiency. The incandescent light bulb uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation). ... This article is about the chemical series. ...


Some old, high-powered lamps used in theater, projection, searchlight, and lighthouse service with heavy, sturdy filaments contained loose tungsten powder within the envelope. From time to time, the operator would remove the bulb and shake it, allowing the tungsten powder to scrub off most of the tungsten that had condensed on the interior of the envelope, removing the blackening and brightening the lamp again. [28]


If a light bulb envelope leaks, the hot tungsten filament reacts with the air, yielding an aerosol of brown tungsten nitride, brown tungsten dioxide, violet-blue tungsten pentoxide, and yellow tungsten trioxide which then deposits on the nearby surfaces or the bulb interior.[29] Tungsten nitride (WN2) is an inorganic compound, a nitride of tungsten. ... Tungsten dioxide is the chemical compound with the formula WO2. ... Tungsten trioxide (tungstic anhydride, WO3) is an intermediary compound in the process of converting tungstates to pure tungsten. ...


The glass bulb of a general service lamp can reach temperatures between 400 and 550 degrees Fahrenheit (200 to 260 degrees Celsius). Lamps intended for high power operation or used for heating purposes will have envelopes made of hard glass or fused quartz. [30]


Electrical characteristics

Incandescent lamps are nearly pure resistive loads with a power factor of 1. This means the actual power consumed (in watts) and the apparent power (in volt-amperes) are equal. The actual resistance of the filament is temperature dependent. The cold resistance of tungsten filament lamps is about 1/15 the resistance when the lamp is lit. For example, a 100 watt, 120 volt lamp has a resistance of 144 Ω when lit, but the cold resistance is much lower (about 9.5 ohms) [31]. Since incandescent lamps are resistive loads, simple triac dimmers can be used to control brightness. Electrical contacts may carry a "T" rating symbol indicating that they are designed to control circuits with the high inrush current characteristic of tungsten lamps. For a 100-watt 120 volt general service lamp, the current stabilizes in about 0.10 seconds, and the lamp reaches 90% of its full brightness after about 0.13 seconds. [32] The power factor of an AC electric power system is defined as the ratio of the real power to the apparent power, and is a number between 0 and 1. ... In the United States the term (Volt-amps) in Electrical terms, means watts. ... Circuit symbol for a thyristor The thyristor is a solid-state semiconductor device with four layers of alternating N and P-type material. ...


Power

Comparison of efficacy by power (120 Volt lamps)
Power (W) Output (lm) Efficacy (lm/W)
5 25 5
15 110 7.3
25 200 8.0
35 350 10.3
40 500 12.5
50 700 13.5
55 800 14.2
60 850 14.5
65 1000 15.0
70 1100 15.7
75 1200 16.0
90 1450 16.1
95 1600 16.8
100 1700 17.0
135 2350 17.4
150 2850 19.0
200 3900 19.5
300 6200 20.7

Incandescent light bulbs are usually marketed according to the electrical power consumed. This is measured in watts and depends mainly on the resistance of the filament, which in turn depends mainly on the filament's length, thickness and material. For two bulbs of the same voltage, type, colour, and clarity, the higher-powered bulb gives more light. For other uses, see Watt (disambiguation). ... The lumen (symbol: lm) is the SI unit of luminous flux. ... Next big thing redirects here. ... For delivered electrical power, see Electrical power industry. ... For other uses, see Watt (disambiguation). ... Electrical resistance is a measure of the degree to which an electrical component opposes the passage of current. ...


The table shows the approximate typical output, in lumens, of standard incandescent light bulbs at various powers. Note that the lumen values for "soft white" bulbs will generally be slightly lower than for standard bulbs at the same power, while clear bulbs will usually emit a slightly brighter light than correspondingly-powered standard bulbs.


Comparison of electricity cost

The kilowatt-hour, is the usual unit of electrical energy purchase. The cost of electricity in the United States normally ranges from $0.06 to $0.18 per kilowatt-hour (kWh), but can be as high as $0.23 per kWh in certain areas such as Hawaii. The watt-hour (symbol W·h) is a unit of energy. ... This article is about the U.S. State. ...


As for any other electrical appliance, the hourly cost of operation can be calculated by multiplying the input in watts by the cost per kilowatt-hour and divding by 1000; for example, a 100-watt lamp operated on electricity that costs 10 cents per kilowatt-hour will cost 100 * 10/1000 = 1 cent per hour to operate.


The desired product of any electric lighting system is illumination (lumens), not power. To compare incandescent lamp operating cost with other light sources, the calculation must also consider the lumens produced by each lamp. For commercial and industrial lighting systems the comparison must also include the required illumination level, effectiveness of the lighting fixtures, the capital cost of the lamp, the labor cost to replace lamps, the various depreciation factors for light output as the lamp ages, effect of lamp operation on heating and air conditioning systems, and also the energy consumption.


Overall cost of lighting must also take into account light lost within the lamp holder fixture; internal reflectors and updated design of lighting fixtures can improve the amount of usable light delivered. Since human vision adapts to a wide range of light levels, a 10% or 20% decrease in lumens may still provide acceptable illumination, especially if the changeover is accompanied by cleaning of lighting equipment or improvements in fixtures.


Physical characteristics

Bulb shapes, sizes, and terms

Incandescent light bulbs come in a range of shapes and sizes. The names of the shapes may be slightly different in some regions. Many of these shapes have a designation consisting of one or more letters followed by one or more numbers, e.g. A55, PAR38. The letters represent the shape of the bulb. The numbers represent the maximum diameter, either in eights of an inch, or in milimetres, depending on the shape and the region. For example, in Europe, Australia and elsewhere, 63mm reflectors are known as R63, whereas in the US they are known as R20 (2.5 inches). However, in both regions, a PAR38 reflector is known as PAR38.


These designations may also apply to non incandescent lamps. For example, compact fluorescent lamps.


Common shapes:

General Service
Light emitted in all directions. Available in either clear or frosted.
Types: General (A), Mushroom
High Wattage General Service
Lamps greater than 200 watts.
Types: Pear-shaped (PS)
Decorative
lamps used in chandeliers, etc.
Types: Candle(B), Twisted Candle, Bent-tip Candle (CA & BA), Flame (F), Fancy Round(P), Globe(G)
Reflector (R)
Reflective coating inside the bulb directs light forward. Flood types (FL) spread light. Spot types (SP) concentrate the light. Reflector (R) bulbs put approximately double the amount of light (foot-candles) on the front central area as General Service (A) of same wattage.
Types: Standard Reflector(R), Elliptical Reflector (ER), Crown Silvered
Parabolic Aluminized Reflector (PAR)
Parabolic Aluminized Reflector (PAR) bulbs control light more precisely. They produce about four times the concentrated light intensity of General Service (A), and are used in recessed and track lighting. Weatherproof casings are available for outdoor spot and flood fixtures.
120V Sizes:PAR 16, 20, 30 and 38
230V Sizes:Par 38 & 56
Available in numerous spot and flood beam spreads. Like all light bulbs, the number represents the diameter of the bulb in 1/8s of an inch. Therefore, a PAR 16 is 2" in diameter, a PAR 20 is 2.5" in diameter, PAR 30 is 3.75" and a PAR 38 is 4.75" in diameter.
Multifaceted Reflector (MR)
HIR
"HIR" means that the bulb has a special coating that reflects infrared back onto the filament. Therefore, less heat escapes, so the filament burns hotter and more efficiently.[33]

Standard fittings

A light bulb with a standard E26 Edison screw base
A light bulb with a standard E26 Edison screw base
The double-contact Bayonet Cap (The bulb shown is actually a CFL.)
The double-contact Bayonet Cap (The bulb shown is actually a CFL.)

Most domestic and industrial light bulbs have a metal fitting (or lamp base) compatible with standard sockets. General Electric introduced standard fitting sizes for tungsten incandescent lamps under the Mazda trademark in 1909. This standard was soon adopted across the United States, and the Mazda name was used by many manufacturers under license through 1945. Image File history File links Size of this preview: 361 × 600 pixelsFull resolution (768 × 1276 pixel, file size: 757 KB, MIME type: image/png) Other versions Original at Image:Gluehlampe 01 KMJ.jpg File historyClick on a date/time to view the file as it appeared at that time. ... Image File history File links Size of this preview: 361 × 600 pixelsFull resolution (768 × 1276 pixel, file size: 757 KB, MIME type: image/png) Other versions Original at Image:Gluehlampe 01 KMJ.jpg File historyClick on a date/time to view the file as it appeared at that time. ... Low-energy light-bulb redirects here. ... GE redirects here. ... Mazda was a trademarked name used by General Electric and others on incandescent light bulbs from 1909 through 1945. ...


Screw thread

Main article: Edison screw

In each designation, the E stands for Edison, who created the screw-base lamp, and the number is the diameter of the screw base in millimeters. (This is even true in North America, where designations for the bulb glass diameter are in eighths of an inch.) There are four common sizes of screw-in sockets used for line-voltage lamps: A 230/240 V AC incandescent light bulb with Edison E27 (27 mm) Male screw base. ... DIAMETER is a computer networking protocol for AAA (Authentication, Authorization and Accounting). ... An inch (plural: inches; symbol or abbreviation: in or, sometimes, ″ - a double prime) is the name of a unit of length in a number of different systems, including English units, Imperial units, and United States customary units. ...

  • candelabra: E12 North America, E10 & E11 in Europe
  • intermediate: E17 North America, E14 (SmallES) in Europe
  • medium or standard: E26 (MES) in North America, E27 (ES) in Europe
  • mogul: E39 North America, E40 (GoliathES) in Europe.

Other screw thread sizes include: Three-branched brass candelabrum without candles Candelabra is the term traditionally referring to a pair (or more) of large, decorative candlesticks often shaped as a column or pedestal and having several arms or branches for holding candles. ...

  • "admedium" size (E29), larger than common lamp sockets, intended to frustrate thieves of bulbs used in public places;
  • miniature size (E5) generally used only for low-voltage applications such as with a battery.

The largest size E39 is now used in large street lights, and high-wattage lamps (such as a 100/200/300-watt three-way) and many non-incandescent high-intensity discharge bulbs. Medium Edison screw (MES) bulbs for 12 volts are also produced for recreational vehicles. Large outdoor Christmas lights use an intermediate base, as do some desk lamps and many microwave ovens. Formerly Emergency exit signs also tended to use the intermediate base (but US and Canadian rules now require more energy-efficient lamps). A medium screw base should not carry more than 25 amperes current; this may limit the practical rating of low-voltage lamps. [34] For other uses, see Battery. ... A high pressure sodium vapor street lamp from Australia. ... “RV” redirects here. ... Microwave oven A microwave oven, or microwave, is a kitchen appliance employing microwave radiation primarily to cook or heat food. ... Emergency Exit, by Manlio Santanelli, is a play written originally in Italian. ...


Bayonet

Bulbs with a bayonet (push-twist) base for use with sockets having spring-loaded base plates, are produced in similar sizes and are given a B, BA or BY designation. These are also common in 12-volt automobile lighting worldwide, in addition to wedge-base lamps which have a partial plastic or even completely glass base. In this case, the wires wrap around to the outside of the bulb, where they press against the contacts in the socket. Miniature Christmas bulbs use a plastic wedge base as well. BC or B22 or B22d or double-contact bayonet cap are used in Australia, India, Ireland, New Zealand and the UK for most 220–240 V mains lamps. A miniature bayonet is used in North America for appliances such as sewing machines and vacuum cleaners. The lighting system of a motor vehicle consists of lighting and signalling devices mounted or integrated to the front, sides and rear of the vehicle. ... Look up wedge in Wiktionary, the free dictionary. ... A bayonet mount A bayonet mount before and after insertion A bayonet mount or bayonet connector is a fastening mechanism that relies on mated surfaces; a male side with one or more pins or slots, and a female receptor with matching slots and a spring that maintains a clamping force. ... Elias Howes lockstitch machine, invented 1845 A sewing machine is a textile machine used to stitch fabric or other material together with thread. ... Regular canister vacuum cleaner for home use. ...


Pin base

A pin base, has two contacts on the underside of the bulb. These are given a G or GY designation, with the number being the center-to-center distance in millimeters. For example, a 4 mm pin base would be indicated as G4 (or GY4). Some common sizes include G4 (4 mm), G6.35 (6.35 mm), G8 (8 mm), GY8.6 (8.6 mm), G9 (9 mm), and GY9.5 (9.5 mm). The second letter (or lack thereof) indicates pin diameter. Some spotlights or floodlights have pins that are broader at the tips, in order to lock into a socket with a twist. Other lamps come in a tube, with blades or dimples at either end. A Source 4 ERS with major parts labeled Stage Lighting instruments are used in stage lighting to illuminate theatrical productions, rock concerts and other performances taking place in live performance venues. ... A Source 4 ERS with major parts labeled Stage Lighting instruments are used in stage lighting to illuminate theatrical productions, rock concerts and other performances taking place in live performance venues. ...


Special lamp bases

There are also special bases for projectors and stage lighting instruments. Projector lamps[35], in particular, may run on unusual voltages (such as 82), perhaps intended as a vendor lock-in or to optimize light output for a particular optical system. Projectors are used for displaying an image on a projection screen or similar surface for the view of an audience. ... A Source 4 ERS with major parts labeled Stage Lighting instruments are used in stage lighting to illuminate theatrical productions, rock concerts and other performances taking place in live performance venues. ... In economics, vendor lock-in, also known as proprietary lock-in, customer lock-in, lock-in is where a customer is dependent on a vendor for products and services and cannot move to another vendor without substantial switching costs, real and/or perceived. ...


Lamps intended for use in optical systems (such as film projectors, microscope illuminators, or theatrical lighting instruments) have bases with alignment features so that the filament is positioned accurately within the optical system. A screw-base lamp may have a random orientation of the filament when the lamp is installed in the socket.


Tubular lamps such as R7S-75 for halogen lamp tubes, in this case a 7 mm diameter socket with 75 mm tube length.[36]


Voltage, light output, and lifetime

See also: Lamp rerating

Incandescent lamps are very sensitive to changes in the supply voltage. These characteristics are of great practical and economic importance.


For a supply voltage V,

  • Light output is approximately proportional to V 3.4
  • Power consumption is approximately proportional to V 1.6
  • Lifetime is approximately inversely proportional to V 16
  • Colour temperature is approximately proportional to V 0.42 [37]

This means that a 5% reduction in operating voltage will more than double the life of the bulb, at the expense of reducing its light output by about 20%. This may be a very acceptable trade off for a light bulb that is in a difficult-to-access location (for example, traffic lights or fixtures hung from high ceilings). So-called "long-life" bulbs are simply bulbs that take advantage of this trade off. Since the value of the electric power they consume is much more than the value of the lamp, general service lamps for illumination usually emphasize efficiency over long operating life; the objective is to minimize the cost of light, not the cost of lamps. [38]


The relationships above are valid for only a few percent change of voltage around rated conditions, but they do indicate that a lamp operated at much lower than rated voltage could last for hundreds of times longer than at rated conditions, albeit with greatly reduced light output. The Centennial Light is a light bulb which is accepted by the Guinness Book of World Records as having been burning almost continuously at a fire station in Livermore, California since 1901. However, the bulb is powered by only 4 watts. A similar story can be told of a 40-watt bulb in Texas which has been illuminated since September 21, 1908. It once resided in an opera house where notable celebrities stopped to take in its glow, but is now in an area museum.[39] The Centennial Light hanging in the Livermore, California Firehouse. ... The Guinness Book of Records (or in recent editions Guinness World Records, and in previous US editions Guinness Book of World Records) is a book published annually, containing an internationally recognized collection of superlatives: both in terms of human achievement and the extrema of the natural world. ... Fire station in Kostroma, Russia (1823-26). ... Livermore is a city in Alameda County, California, United States. ... For other uses, see Texas (disambiguation). ... is the 264th day of the year (265th in leap years) in the Gregorian calendar. ... Year 1908 (MCMVIII) was a leap year starting on Wednesday (link will display the full calendar) of the Gregorian calendar (or a leap year starting on Tuesday of the 13-day-slower Julian calendar). ... New York State Theater, Lincoln Center, home of the New York City Opera Bolshoi Theatre. ... For other uses, see Museum (disambiguation). ...


In flood lamps used for photographic lighting, the trade-off is made in the other direction. Compared to general service bulbs, for the same power, these bulbs produce far more light, and (more importantly) light at a higher colour temperature, at the expense of greatly reduced life (which may be as short as 2 hours for a type P1 lamp). The upper limit to the temperature at which metal incandescent bulbs can operate is the melting point of the metal. Tungsten is the metal with the highest melting point. A 50-hour-life projection bulb, for instance, is designed to operate only 50 °C (90 °F) below that melting point. Such a lamp may achieve up to 22 lumens/watt , compared with 17.5 for a 750-hour general service lamp. [40]-1... The melting point of a solid is the temperature range at which it changes state from solid to liquid. ... For other uses, see Celsius (disambiguation). ... For other uses, see Fahrenheit (disambiguation). ...


Lamps designed for different voltages have different luminous efficacy. For example a 100 watt 120 volt lamp will produce about 17.1 lumens per watt. A lamp with the same rated lifetime but designed for 230 V would produce only around 12.8 lumens/watt, and a similar lamp designed for 30 volts (train lighting) would produce as much as 19.8 lumens/watt. [41]


Lamps also vary in the number of support wires used for the tungsten filament. Each additional support wire makes the filament mechanically stronger, but removes heat from the filament, creating another trade-off between efficiency and long life. Many modern general service 120 volt lamps use no additional support wires, but lamps designed for "rough service" often have several support wires and lamps designed for "vibration service" may have as many as five. Lamps designed for low voltages (for example, 12 volts) generally have filaments made of much heavier wire and do not require any additional support wires. Very low voltages are inefficient since the lead wires would conduct too much heat away from the filament, so the practical lower limit is 1.5 volts. Very long filaments for high voltages are fragile, and lamp bases become more difficult to insulate so lamps for illumination are not made with rated voltages over 300 V. [42] Some infrared heating elements are made for higher voltages, but these use tubular bulbs with widely-separated terminals.


Luminous efficacy and efficiency

Close-up of a tungsten filament inside a halogen lamp. The two ring-shaped structures left and right are filament supports.
Close-up of a tungsten filament inside a halogen lamp. The two ring-shaped structures left and right are filament supports.

Approximately 90% of the power consumed by an incandescent light bulb is emitted as heat, rather than as visible light. [43] Image File history File linksMetadata Download high-resolution version (1110x1125, 215 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Tungsten Incandescent light bulb Metadata This file contains additional information, probably added from the digital camera or scanner... Image File history File linksMetadata Download high-resolution version (1110x1125, 215 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Tungsten Incandescent light bulb Metadata This file contains additional information, probably added from the digital camera or scanner... For other uses, see Heat (disambiguation) In physics, heat, symbolized by Q, is energy transferred from one body or system to another due to a difference in temperature. ... For other uses, see Light (disambiguation). ...


Luminous efficacy is a ratio of the visible light energy emitted ( the luminous flux) to the total power input to the lamp. It is measured in lumens per watt (lm/W). The maximum efficacy possible is 683 lm/W for monochromatic green light at 555 nanometres wavelength, the peak sensitivity of the human eye. For white light, the maximum luminous efficacy is around 240 lumens/watt. Luminous efficiency is the ratio of the luminous efficacy to this maximum possible value. It is expressed as a number between 0 and 1, or as a percentage.[44] However, the term luminous efficiency is often used for both quantities. Two related measures are the overall luminous efficacy and overall luminous efficiency, which divide by the total power input rather than the total radiant flux. This takes into account more ways that energy might be wasted and so they are never greater than the standard luminous efficacy and efficiency. The term "luminous efficiency" is often misused, and in practice can refer to any of these four measures. Luminous efficacy is a property of light sources, which indicates what portion of the emitted electromagnetic radiation is usable for human vision. ... The lumen (symbol: lm) is the SI unit of luminous flux. ... For other uses, see Watt (disambiguation). ...


The chart below lists values of overall luminous efficacy and efficiency for several types of general service, 120 volt, 1000-hour lifespan incandescent bulb, and several idealized light sources. A similar chart in the article on luminous efficacy compares a broader array of light sources to one another. Luminous efficacy is a property of light sources, which indicates what portion of the emitted electromagnetic radiation is usable for human vision. ...

Type Overall luminous efficiency Overall luminous efficacy (lm/W)
40 W tungsten incandescent 1.9% 12.6[45]
60 W tungsten incandescent 2.1% 14.5[45]
100 W tungsten incandescent 2.6% 17.5[45]
glass halogen 2.3% 16
quartz halogen 3.5% 24
high-temperature incandescent 5.1% 35[46]
ideal black-body radiator at 4000 K 7.0% 47.5[47]
ideal black-body radiator at 7000 K 14% 95[47]
ideal white light source 35.5% 242.5[46]
ideal monochromatic 555 nm (green) source 100% 683[48]

A 100 W bulb for 120 V systems, produces 17.5 lm/W, compared to a theoretical "ideal" of 242.5 lm/W for white light. Unfortunately, tungsten filaments radiate mostly infrared radiation at temperatures where they remain solid (below 3683 kelvins). Donald L. Klipstein explains it this way: "An ideal thermal radiator produces visible light most efficiently at temperatures around 6300 °C (6600 K or 11 500 °F). Even at this high temperature, a lot of the radiation is either infrared or ultraviolet, and the theoretical luminous efficiency is 95 lumens per watt."[46] No known material can be used as a filament at this ideal temperature, which is hotter than the sun's surface. The spectrum emitted by a blackbody radiator does not match the sensitivity characteristics of the human eye. An upper limit for incandescent lamp luminous efficacy is around 52 lumens per watt, the theoretical value emitted by tungsten at its melting point. [49] As the temperature decreases, the peak of the black-body radiation curve moves to lower intensities and longer wavelengths. ... This box:      For other uses, see Solid (disambiguation). ... For other uses, see Kelvin (disambiguation). ... As the temperature decreases, the peak of the black body radiation curve moves to lower intensities and longer wavelengths. ...


For a given quantity of light, an incandescent light bulb, produces more heat (and consumes more power) than a fluorescent lamp. Incandescent lamps' heat output increases load on air conditioning in the summer, but the heat from lighting can contribute to building heating in cold weather. [50] Fluorescent lamps Assorted types of fluorescent lamps. ... Note: in the broadest sense, air conditioning can refer to any form of heating, ventilation, and air-conditioning. ...


Quality halogen incandescent lamps have higher efficacy, which will allow a 60 W bulb to provide nearly as much light as a non-halogen 100 W. Also, the lower wattage halogen lamp can be designed to produce the same amount of light as a 60 W non-halogen lamp, but with much longer life. The incandescent light bulb uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation). ...


Alternatives to standard incandescent lamps for general lighting purposes include:

None of these devices rely on incandescence to produce light. Instead, all these devices produce light by the transition of electrons from one energy level to another. These mechanisms produce discrete spectral lines and so are not associated with the broad "tail" of invisible infrared emissions produced by incandescent emitters, which is energy not usable for illumination. By careful selection of which electron energy level transitions are used, the spectrum emitted can be tuned to either mimic the appearance of incandescent sources or else produce different color temperatures of white for visible light. Fluorescent lamps Assorted types of fluorescent lamps. ... Low-energy light-bulb redirects here. ... 15 kW Xenon short-arc lamp used in IMAX projectors High-intensity discharge (HID) lamps include these types of electrical lamps: mercury vapor, metal halide (also HQI), high-pressure sodium (Son), low-pressure sodium (Sox) and less common, xenon short-arc lamps. ... LED Lamp with GU10 twist lock fitting, intended to replace halogen reflector lamps. ... A spectral line is a dark or bright line in an otherwise uniform and continuous spectrum, resulting from an excess or deficiency of photons in a narrow frequency range, compared with the nearby frequencies. ... The CIE 1931 x,y chromaticity space, also showing the chromaticities of black-body light sources of various temperatures, and lines of constant correlated color temperature Color temperature is a characteristic of visible light that has important applications in photography, videography, publishing and other fields. ...


Laws and regulations to discontinue use

Main article: Banning of incandescent lightbulbs

Due to the higher energy usage of incandescent light bulbs in comparison to more energy efficient alternatives, like compact fluorescent lamps and LED lamps, some governments have passed laws and regulations that have started to phase out their usage. Brazil and Venezuela started to phase them out in 2005, and other nations are planning scheduled phase-outs: Ireland in 2009, Australia in 2010, Canada in 2012, and the U.S. between 2012 and 2014. Most of these laws and regulations do not ban the usage of incandescents, but rather ban their sale. Low-energy light-bulb redirects here. ... LED Lamp with GU10 twist lock fitting, intended to replace halogen reflector lamps. ...


Efforts to improve efficiency

Various efforts to improve the efficiency of incandescent lamps have been made recently, due to legislation and other movements to ban incandescent lamps. The consumer lighting division of General Electric has announced that they are working on what they have dubbed "high efficiency incandescent" (HEI) lamps, which are ultimately expected to be four times as efficient as current incandescent lamps, although their initial production goal is to be 30 lumens per watt or twice as efficient. [51][52] GE redirects here. ...


In 2006, David Cunningham, who has produced many innovations in entertainment lighting, filed for a US Patent for a lamp using an infrared reflector. [53] This is a current Stagecraft collaboration! Please help improve it to good article standard. ...


The US Department of Energy at Sandia National Laboratories is also currently developing a filament lamp with improved efficiency from 5% to 60%.[54][55] It has been suggested that Sandia Base be merged into this article or section. ...


See also

Energy Portal

Image File history File links Portal. ... The Centennial Light hanging in the Livermore, California Firehouse. ... Fluorescent lamps Assorted types of fluorescent lamps. ... A light bulb The lightbulb joke is an example of an endless-variations joke and has possibly thousands of versions covering every imaginable culture, belief, occupation and special-interest group. ... The worlds longest lasting light bulb is the Centennial Light located at 4550 East Avenue, Livermore, California. ... LED redirects here. ... A chandelier light fixture A light fixture or luminaire is an electrical device used to create artificial light or illumination in architecture. ... LED Lamp with GU10 twist lock fitting, intended to replace halogen reflector lamps. ... A Common Household Light bulb This is a list of sources of light, including both natural and artificial sources, and both processes and devices. ... Luminous efficacy is a property of light sources, which indicates what portion of the emitted electromagnetic radiation is usable for human vision. ... A typical MR16 lamp MR16 (sometimes referred to as MR-16) is a standard format for halogen reflector lamps made by a variety of manufactures. ... This cosmetics store has lighting levels over twice recommended levels and sufficient to trigger headaches and other health effects Over-illumination is the presence of lighting intensity (illuminance) beyond that required for a specified activity. ... Photopic (black) and scotopic [1] (green) luminosity functions. ... Spectrometer A spectrometer is an optical instrument used to measure properties of light over a specific portion of the electromagnetic spectrum, typically used in spectroscopic analysis to identify materials. ... Edison redirects here. ...

References

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  16. ^ The History of Tungsram.
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  25. ^ Toshiba Lighting Products Miniature Lamp Characteristics, retrieved 2008 March 23
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  29. ^ Hochgraf, Fredrick G. (1985). Review of Lamp Examination for ON or OFF in Traffic Accidents. Northwestern University Traffic Institute. Retrieved on 2007-05-02.
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  33. ^ Lighting Glossary
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  35. ^ The Basics About Projector Lamps. Published by PartStore, accessed on June 29, 2007.
  36. ^ butiken.su.se Stockholms universitet."MT0414 Lampa, halogen, 300W, R7s-15 Haloline" / see picture
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  46. ^ a b c Klipstein, Donald L. (1996). The Great Internet Light Bulb Book, Part I. Retrieved on 2006-04-16.
  47. ^ a b Black body visible spectrum
  48. ^ See luminosity function.
  49. ^ General Electric TP-110 page 19
  50. ^ Prof. Peter Lund, Helsinki University of Technology,[2] on p. C5 in Helsingin Sanomat Oct. 23, 2007.
  51. ^ Daley, Dan (February 2008), “Incandescent's Not-So-Dim Future”, Projection Lights and Staging News (PLSN) (Timeless Communications Corp.) 09 (1): 46 
  52. ^ GE Announces Advancement in Incandescent Technology; New High-Efficiency Lamps Targeted for Market by 2010
  53. ^ Cunningham, David (2006), Incandescent lamp incorporating extended high-reflectivity IR coating and lighting fixture incorporating such an incandescent lamp (United States Patent 20060226777) 
  54. ^ Proposed Bulb Ban Causes Chain Reaction”, Projection Lights and Staging News (PLSN) Online, January 2008, <http://www.plsn.com/index.php?option=com_content&task=view&id=1606&Itemid=41> 
  55. ^ Daley, Dan (February 2008), “Incandescent's Not-So-Dim Future”, Projection Lights and Staging News (PLSN) (Timeless Communications Corp.) 09 (1): 46 

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Incandescent light bulb
For devices such as table lamps and reading lamps, see Light fixture. ... Not to be confused with lightning. ... Molten glassy material glows orange with incandescence in a vitrification experiment. ... The incandescent light bulb uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation). ... A Parabolic Aluminized Reflector light, or PAR light, is a type of light commonly used in motion picture production when a substantial amount of light is required for a scene. ... Nernst lamp, complete, model B with cloche, DC-lamp 0. ... The Centennial Light hanging in the Livermore, California Firehouse. ... Image File history File links Size of this preview: 361 × 600 pixelsFull resolution (768 × 1276 pixel, file size: 757 KB, MIME type: image/png) Other versions Original at Image:Gluehlampe 01 KMJ.jpg File historyClick on a date/time to view the file as it appeared at that time. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized Cadmium selenide (CdSe) quantum dots. ... Fluorescent lamps Assorted types of fluorescent lamps. ... Low-energy light-bulb redirects here. ... In contrast with all other electrical lamps that use electrical connections through the lamp envelope to transfer power to the lamp, in electrodeless lamps the power needed to generate light is transferred from the outside of the lamp envelope by means of (electro)magnetic fields. ... 15 kW Xenon short-arc lamp used in IMAX projectors High-intensity discharge (HID) lamps include these types of electrical lamps: mercury vapor, metal halide (also HQI), high-pressure sodium (Son), low-pressure sodium (Sox) and less common, xenon short-arc lamps. ... A Mercury-vapor lamp is a gas discharge lamp which uses mercury in an excited state to produce light. ... Example of a light source using a broad spectrum metal halide lamp pointing upward towards the sky. ... 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  Results from FactBites:
 
incandescent, incandescent light bulb, incandescent lamp, incandescent light, incandescent bulb, incandecsnt light ... (611 words)
Halogen bulbs are technically incandescent light bulbs - illumination is produced in both when a tungsten filament is heated sufficiently to emit light or "incandescence." The difference between the two is in the composition of the glass envelope and the gas inside the envelope.
When the tungsten filament is heated it evaporates and deposits metal on the cooler glass envelope (this is why incandescent bulbs appear fl at the end of life).
This process requires incandescent bulb filaments to be heated less than optimally to give the bulb a reasonable life.
ipedia.com: Incandescent light bulb Article (2593 words)
The incandescent 'light bulb uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation).
The invention of the light bulb is sometimes attributed to Thomas Alva Edison, who made contributions to its development and marketing, but today it is well-known that Heinrich Göbel built functional bulbs three decades earlier.
The incandescent light bulb is still widely used in domestic applications, and is the basis of most portable lighting (for instance, some car headlamps and electric torcheses).
  More results at FactBites »

 
 

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