Gas-discharge lamp
Gas-discharge lampsare a family of artificial light sources that generate light by sending anelectric dischargethrough anionizedgas, aplasma.
Typically, such lamps use a noble gas(argon,neon,krypton,andxenon) or a mixture of these gases. Some include additional substances, such asmercury,sodium,andmetalhalides,which are vaporized during start-up to become part of the gas mixture.
Single-ended self-starting lamps are insulated with amicadisc and contained in aborosilicate glassgas discharge tube (arc tube) and a metal cap.[1][2]They include thesodium-vapor lampthat is the gas-discharge lamp in street lighting.[3][4][1][2]
In operation, some of the electrons are forced to leave theatomsof the gas near theanodeby theelectric fieldapplied between the two electrodes, leaving these atoms positivelyionized.The free electrons thus released flow to the anode, while thecationsthus formed are accelerated by the electric field and flow towards thecathode.
The ions typically cover only a very short distance before colliding with neutral gas atoms, which give the ions their electrons. The atoms which lost an electron during the collisions ionize and speed toward the cathode while the ions which gained an electron during the collisions return to alower energy state,releasing energy in the form ofphotons.Light of a characteristic frequency is thus emitted. In this way, electrons are relayed through the gas from the cathode to the anode.
The color of the light produced depends on theemission spectraof the atoms making up the gas, as well as the pressure of the gas,current density,and other variables. Gas discharge lamps can produce a wide range of colors. Some lamps produceultravioletradiation which is converted to visible light by afluorescentcoating on the inside of the lamp's glass surface. Thefluorescent lampis perhaps the best known gas-discharge lamp.
Compared toincandescent lamps,gas-discharge lamps offer higherefficiency,[5][6]but are more complicated to manufacture and most exhibitnegative resistance,causing the resistance in the plasma to decrease as the current flow increases. Therefore, they usually require auxiliary electronic equipment such asballaststo control current flow through the gas, preventing current runaway (arc flash).
Some gas-discharge lamps also have a perceivable start-up time to achieve their full light output. Still, owing to their greater efficiency, gas-discharge lamps were preferred overincandescent lightsin many lighting applications, until recent improvements inLED lamptechnology.[citation needed]
History
[edit]The history of gas-discharge lamps began in 1675 when the French astronomerJean Picardobserved that the empty space in his mercurybarometerglowed as the mercury jiggled while he was carrying the barometer.[7]Investigators, includingFrancis Hauksbee,tried to determine the cause of the phenomenon. Hauksbee first demonstrated a gas-discharge lamp in 1705.[8]He showed that an evacuated or partially evacuated glass globe, in which he placed a small amount of mercury, while charged by static electricity could produce a light bright enough to read by. The phenomenon of electric arc was first described byVasily V. Petrovin 1802.[9][10][11]In 1809, SirHumphry Davydemonstrated theelectric arcat theRoyal Institutionof Great Britain.[12][13]Since then, discharge light sources have been researched because they create light from electricity considerably more efficiently thanincandescent light bulbs.
The father of the low-pressure gas discharge tube was German glassblowerHeinrich Geissler,who beginning in 1857 constructed colorful artisticcold cathodetubes with different gases in them which glowed with many different colors, calledGeissler tubes.It was found that inert gases such as thenoble gasesneon, argon, krypton or xenon, as well ascarbon dioxideworked well in tubes. This technology was commercialized by the French engineerGeorges Claudein 1910 and becameneon lighting,used inneon signs.
The introduction of the metal vapor lamp, including various metals within the discharge tube, was a later advance. The heat of the gas discharge vaporizes some of the metal and the discharge is then produced almost exclusively by the metal vapor. The usual metals aresodiumandmercuryowing to their visible spectrum emission.
One hundred years of research later led to lamps without electrodes which are instead energized by microwave or radio-frequency sources. In addition, light sources of much lower output have been created, extending the applications of discharge lighting to home or indoor use.
The "Ruhmkorff" lamp
[edit]Ruhmkorff lamps were an early form of portable electric lamp, named afterHeinrich Daniel Ruhmkorffand first used in the 1860s. The lamp consisted of aGeissler tubethat was excited by a battery-powered Ruhmkorffinduction coil;an early transformer capable of converting DC currents of low voltage into rapid high-voltage pulses. Initially the lamp generated white light by using a Geissler tube filled with carbon dioxide. However, the carbon dioxide tended to break down. Hence in later lamps, the Geissler tube was filled with nitrogen (which generated red light), and the clear glass was replaced withuranium glass(which fluoresced with a green light).[14]
Intended for use in the potentially explosive environment of mining, as well as oxygen-free environments like diving or for a heatless lamp for possible use in surgery, the lamp was actually developed both by Alphonse Dumas, an engineer at the iron mines ofSaint-Priestand of Lac, nearPrivas,in the department ofArdèche,France, and by Dr Camille Benoît, a medical doctor in Privas.[15]In 1864, the French Academy of Sciences awarded Dumas and Benoît a prize of 1,000 francs for their invention.[16]The lamps, cutting-edge technology in their time, gained fame after being described in several ofJules Verne's science-fiction novels.[17]
Color
[edit]Each gas, depending on its atomic structure emits radiation of certain wavelengths, itsemission spectrum,which determines the color of the light from the lamp. As a way of evaluating the ability of a light source to reproduce the colors of various objects being lit by the source, theInternational Commission on Illumination(CIE) introduced thecolor rendering index(CRI). Some gas-discharge lamps have a relatively low CRI, which means colors they illuminate appear substantially different from how they do under sunlight or other high-CRI illumination.
| Gas | Color | Spectrum | Notes | Image |
|---|---|---|---|---|
| Helium | Whitetoorange;under some conditions may begray,blue,orgreen-blue. | 
|
Used by artists for special-purpose lighting. | 
|
| Neon | Red-orange | 
|
Intense light. Used frequently inneon signsandneon lamps. | 
|
| Argon | Violettopale lavender blue | 
|
Often used together withmercury vapor. | 
|
| Krypton | Grayoff-whitetogreen.At high peak currents,bright blue-white. | 
|
Used by artists for special-purpose lighting. | 
|
| Xenon | Grayorblue-graydim white. At high peak currents,very bright green-blue. | 
|
Used inflashlamp,xenon HID headlamps,andxenon arc lamps. | 
|
| Nitrogen | Similar toargonbut duller, morepink;at high peak currentsbright blue-white. | 
|
used in theMoore lamp(historically) | 
|
| Oxygen | Violettolavender,dimmer thanargon | 
|
| |
| Hydrogen | Lavenderat low currents,pinktomagentaover 10 mA | 
|
| |
| Water vapor | Similar tohydrogen,dimmer | |||
| Carbon dioxide | Blue-whitetopink,at lower currents brighter thanxenon | Used incarbon dioxide laser,theMoore lamp(historically). | 
| |
| Carbon Monoxide | Similar tocarbon dioxide. | |||
| Methane | Magenta,but morepurpleandpink. | |||
| Chlorine | Limeorchartreuse. | used in theHalogen lamp(historically) | ||
| Fluorine | Mustardorivory. | used in theHalogen lamp(historically) | ||
| Ammonia | Fuchsia,but morepurple. | |||
| Ozone | Indigoornavy,similar tooxygen | |||
| Mercury vapor | Light blue,intenseultraviolet | 
|
Ultravioletnot shown on this spectral image.
Used in combination withphosphorsused to generate many colors of light. Widely used inmercury-vapor lampsandfluorescent tubes. |
|
| Sodium vapor(low pressure) | Bright orange-yellow | 
|
Widely used insodium-vapor lamps. | 
|
Types
[edit]Lamps are divided into families based on the pressure of gas, and whether or not the cathode is heated.Hot cathodelamps have electrodes that operate at a high temperature and are heated by the arc current in the lamp. The heat knockselectronsout of the electrodes bythermionic emission,which helps maintain the arc. In many types the electrodes consist ofelectrical filamentsmade of fine wire, which are heated by a separate current at startup, to get the arc started.Cold cathodelamps have electrodes that operate at room temperature. To start conduction in the lamp a high enough voltage (thestriking voltage) must be applied to ionize the gas, so these lamps require higher voltage to start.
Low pressure discharge lamps
[edit]Low-pressure lamps have working pressure much less than atmospheric pressure. For example, commonfluorescent lampsoperate at a pressure of about 0.3% of atmospheric pressure.
Fluorescent lamps,a heated-cathode lamp, the most common lamp in office lighting and many other applications, produces up to 100lumensperwatt
Neon lighting,a widely used form of cold-cathode specialty lighting consisting of long tubes filled with various gases at low pressure excited by high voltages, used as advertising inneon signs.
Low pressuresodium lamps,the most efficient gas-discharge lamp type, producing up to 200 lumens per watt, but at the expense of very poorcolor rendering.The almostmonochromaticyellow light is only acceptable for street lighting and similar applications.
A small discharge lamp containing abi-metallicswitchis used tostart a fluorescent lamp.In this case the heat of the discharge is used to actuate the switch; the starter is contained in an opaque enclosure and the small light output is not used.
Continuous glow lamps are produced for special applications where the electrodes may be cut in the shape of alphanumeric characters and figural shapes.[18]
A flicker light bulb, flicker flame light bulb or flicker glow lamp is a gas-discharge lamp which produces light byionizingagas,usuallyneonmixed withheliumand a small amount ofnitrogengas, by an electric current passing through two flame shapedelectrodescreens coated with partially decomposedbarium azide.The ionized gas moves randomly between the two electrodes which produces a flickering effect, often marketed as suggestive of a candle flame (see image).[19]
High pressure discharge lamps
[edit]High-pressure lamps have a discharge that takes place in gas under slightly less to greater than atmospheric pressure. For example, a high pressure sodium lamp has an arc tube under 100 to 200torrpressure, about 14% to 28% of atmospheric pressure; some automotive HID headlamps have up to 50baror fifty times atmospheric pressure.
Metal halide lampsproduce almost white light, and attain 100 lumen per watt light output. Applications include indoor lighting of high buildings, parking lots, shops, sport terrains.
High pressure sodium lamps,producing up to 150 lumens per watt produce a broader light spectrum than the low pressure sodium lamps. Also used for street lighting, and for artificialphotoassimilationfor growing plants
High pressuremercury-vapor lampsare the oldest high pressure lamp type and have been replaced in most applications by metal halide and the high pressure sodium lamps. They require a shorter arc length.
High-intensity discharge lamps
[edit]
A high-intensity discharge (HID) lamp is a type ofelectrical lampwhich produces light by means of an electric arc betweentungstenelectrodeshoused inside a translucent or transparentfused quartzor fusedaluminaarc tube. Compared to other lamp types, relatively high arc power exists for the arc length. Examples of HID lamps includemercury-vapor lamps,metal halide lamps,ceramic discharge metal halide lamps,sodium vapor lampsandxenon arc lamps
HID lamps are typically used when high levels of light and energy efficiency are desired.
Other examples
[edit]TheXenon flash lampproduces a single flash of light in the millisecond-microsecond range and is commonly used in film,photographyand theatrical lighting. Particularly robust versions of this lamp, known asstrobe lights,can produce long sequences of flashes, allowing for thestroboscopic examination of motion.This has found use in the study of mechanical motion, in medicine and in the lighting of dance halls.
Alternatives
[edit]- Incandescent lamps:They have low manufacturing costs;[20]
- White LED lamp.The efficiency of white LED lamps is 61-200 lm/W.[21]
- Battery-powered lanterns (filling with krypton or xenon).
See also
[edit]References
[edit]- ^ab"The Low Pressure Sodium Lamp".
- ^ab"The Low Pressure Sodium Lamp".
- ^"Lighting Comparison: LED vs High Pressure Sodium/Low Pressure Sodium".www.stouchlighting.com.
- ^"The Sodium Lamp - How it works and history".edisontechcenter.org.
- ^"Types of Lighting".Energy.gov.US Department of Energy.Retrieved10 June2013.
- ^"Lighting technologies: a guide to energy-efficient illumination"(PDF).Energy Star.US Environmental Protection Agency.Retrieved10 June2013.
- ^See:
- (Staff) (1676)."Experience faire à l'Observatoire sur la Barometre simple touchant un nouveau Phenomene qu'on y a découvert"[Experiment done at the [Paris] observatory on a simple barometer concerning a new phenomenon that was discovered there].Journal des Sçavans (Paris edition)(in French): 112–113.From pp. 112–113:"On sçait que le Barometre simple n'est autre chose qu'un tuyau de verre… toutes les circonstances qu'on y découvrira."(One knows that the simple barometer is nothing more than a glass tube [that is] hermetically sealed at the top and open at the bottom, in which there is mercury which usually stands at a certain height, the remainder [of the tube] above being void. Mr Picard has one of them at the observatory [in Paris] which in the dark — when one shakes it enough to make the mercury jiggle — makes sparks and throws a certain flickering light which fills all of the part of the tube that's void: but it happens during each swing only in the void and only during the descent of the mercury. One has tried to perform the same experiment on various other barometers of the same composition; but so far one has succeeded with only [this] one. As one has resolved to examine the thing in every way, we will give at greater length all the circumstances of this as one discovers them.)
- Reprinted in:(Staff) (1676)."Experience faire à l'Observatoire sur la Barometre simple touchant un nouveau Phénomène qu'on y a découvert"[Experiment done at the [Paris] observatory on a simple barometer concerning a new phenomenon that was discovered there].Journal des Sçavans (Amsterdam edition)(in French): 132.
- (Staff) (1694)."Sur la lumière du baromètre"[On the light of the barometer].Histoire de l'Académie Royale des Sciences(in French).2:202–203.From p. 202:"Vers l'année 1676, M. Picard faisant transporter son Baromètre,… il ne s'en trouva aucun qui fit de la lumière."(Towards the year 1676, [while] Mr Picard [was] transporting his barometer from the observatory [in Paris] to the port of Saint Michel during the night, he perceived a light in the part of the tube where the mercury was moving; this phenomenon surprising him, he immediately announced it to the[Journal des] Sçavans,and those who had barometers having examined them, they found nothing which made light.) By the time of Picard's death (1682), his barometer had lost its ability to produce light. However, after Philippe de La Hire (1640–1718) restored Picard's barometer, it once again produced light. Cassini (1625–1712) also owned a barometer that produced light.
- See also:Barometric light
- ^Hauksbee, Francis (1 January 1705)."Several experiments on the mercurial phosphorus, made before the Royal Society, at Gresham-College".Philosophical Transactions of the Royal Society of London.24(303): 2129–2135.doi:10.1098/rstl.1704.0096.S2CID186212654.
- ^Petrov, Vasily (1803).Извѣстіе о Гальвани-Вольтовскихъ Опытахъ[News of Galvanic-Voltaic Experiments] (in Russian). Saint Petersburg, Russia: Printing House of the State Medical College.From pp. 163–164: "Естьли на стеклянную плитку или на скамеечку со стеклянными ножками будуть положеныдва или три куска древесного угля,…и отъ которого темный покой довольно ясно освѣщенъ быть можетъ. "(If on a glass plate or on a bench with glass legs there be placed two or three pieces of charcoal, capable of producing light-bearing phenomena by means of the Galvanic-Voltaic fluid, and if there are then insulated metal conductors (electrodes), in communication with both poles of a huge battery, bring these closer to each other to a distance [i.e., separation] of one to three lines [2.5-7.5 mm]; then there is between them a very bright white light or flame, from which these coals burn quickly or slowly, and by which the darkness may be quite clearly illuminated.)
- ^Anders, Andre (2003)."Tracking down the origin of arc plasma science. II. Early continuous discharges".IEEE Transactions on Plasma Science.31(5): 1060–1069.Bibcode:2003ITPS...31.1060A.doi:10.1109/TPS.2003.815477.S2CID11047670.
- ^Petrov also observed electric discharges through low-pressure air. From (Petrov, 1803), p. 176: "Впрочемъ, свѣтъ, сопровождавшій теченіе Гальвани-Вольтовской жидкости въ безвоздушномъ мѣстѣ, былъ яркій, белаго цвѣта, и при томъ не рѣдко оть разкаленнаго конца иголки, либо и ото дна стакана отскакивали искры или какъ бы маленькія звѣздочки." (However, the light accompanying the flow of the Galvanic-Voltaic fluid in the airless space was bright, white in color; and at the same time, not rarely from the incandescent ends of the needles [i.e., electrodes] or from the bottom of the glass, came sparks like small stars.) From (Petrov, 1803), p. 190: "3) Електрическій свѣтъ въ весьма изтонченномъ воздухѣ предстовляетъ несравненно величественнѣйшія явленія, нежели какія могъ я примѣтить отъ свѣта Гальвани-Вольтовской жидкости." (Electric light in very rarefied air presents an incomparably more majestic phenomenon than any that I could perceive from the light of the Galvanic-Voltaic fluid.)
- ^In 1801 and 1802, Davy observed bright electrical sparks, but not a continuous arc. His battery lacked sufficient voltage and current to sustain an electric arc.
- Davy, H. (1802)."Account of some experiments in Galvanic electricity, made in the theatre of the Royal Institution".Journals of the Royal Institution of Great Britain.1:165–167.
- Davy, H. (1802)."Account of some experiments made in the laboratory of the Royal Institution, relating to the agencies of Galvanic electricity, in producing heat, and in effecting changes in different fluid substances".Journals of the Royal Institution of Great Britain.1:209–214.
- (Ayrton, 1902), pp. 20-21.
- Davy, Humphry (1810)."The Bakerian Lecture. An account of some new analytical researches on the nature of certain bodies, particularly the alkalies, phosphorus, sulphur, carbonaceous matter, and the acids hitherto undecompounded; with some general observations on chemical theory".Philosophical Transactions of the Royal Society of London.100:39–104.From p. 47: "… the electricity passed through the vapour of the potassium, producing a most brilliant flame, of from half an inch to an inch and a quarter in length;…"
- (Ayrton, 1902), pp. 24–27.
- ^For the early history of electric arcs, see:Ayrton, Hertha (1902).The Electric Arc.New York City, New York, USA: D. Van Nostrand Co. pp. 19 ff.
- ^Paolo Brenni (2007)"Uranium glass and its scientific uses,"Archived2014-06-30 at theWayback MachineBulletin of the Scientific Instrument Society,no. 92, pages 34–39; see page 37.
- ^See:
- A. Dumas and Benoit (1862)"Physique Appliquée — Note sur un appareil propre à éclairer les ouvriers mineurs dans leurs travaux souterrains au moyen de la lumière d'induction"(Applied physics — Note on an apparatus suitable for providing light for miners in their underground work by means of the induction lamp),Comptes Rendus,vol. 55, pages 439–440.
- Dumas,"Note descriptive de la lampe photo-électrique",Bulletin de la Société de l'Industrie Minérale,vol. 9, pages 5–14 (1863–1864).
- "Lampe Dumas,"Bulletin de la Société de l'Industrie Minérale,vol. 9, pages 113–117 (1863–1864).
- "Note sur la lampe électrique de Dumas et Benoît",Bulletin de la Société de l'Industrie Minérale,vol. 9, pages 118–120 (1863–1864).
- Bulletin des Lois de l'Empire Français,series 9, vol. 23,page 639(1864); see patent application no. 1160°.
- "New safety light for coal mines",Journal of the Franklin Institute,3rd series, vol. 49, pages 262–263 (1865). Reprinted from theAthenæum(literary magazine of London, England), February 25, 1865.
- Théodose du Moncel,"Application à l'éclairage des galeries de mines,"Notice sur l'appareil d'induction électrique de Ruhmkorff(Paris, France: Gauthier-Villars, 1867), pages 394–398.
- See also: Andreas Fehrmann's Jules Verne collection: "Jules Verne und die Elektrizität: Kapitel 2: Die Ruhmkorfflampe" [in German]. Available on-line at:Jules Verne.
- ^"Prix dit des arts insalubres",Comptes rendus,60:273 (1865).
- ^Journey to the Center of the Earth(1864),From the Earth to the Moon(1865), and20,000 Leagues Under the Sea(1869).
- ^"kilokat's ANTIQUE LIGHT BULB site: neon lamps".bulbcollector.com.
- ^US patent 3238408,Kayatt Philip J., "Flicker glow lamps", issued 1966-03-1
- ^"FAQ: phasing out conventional incandescent bulbs".europa.eu.RetrievedJuly 22,2022.
- ^"LED Light Bulb".yourelectricianbrisbane.com.au.15 March 2022.RetrievedJuly 22,2022.
Further reading
[edit]- Waymouth, John (1971).Electric Discharge Lamps.Cambridge, MA: The M.I.T. Press.ISBN978-0-262-23048-3.
- National Highway Traffic Safety Administration."Glare from headlamps and other front mounted lamps".Federal Motor Vehicle Safety Standard No. 108.US Department of Transportation. Archived fromthe originalon 2011-09-27.Retrieved2006-01-23.
External links
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