Also wouldn't want to produce RFI buy using an undisciplined switching supply…. In high pressure discharge lamps, the applied gas pressure may still be below atmospheric pressure, e.g. A gas discharge lamp is a light source that generates light by creating an electrical discharge through an ionized gas. Electric discharge lamp, also called Vapour Lamp, lighting device consisting of a transparent container within which a gas is energized by an applied voltage and thereby made to glow. There are also electrode-less lamps, where the electric energy is introduced in other ways, typically with a radio frequency or microwave field. Due to the need of triggering, possibly also boosting and because of the negative differential impedance in certain regimes, most gas discharge lamps cannot be operated simply by applying a constant voltage, as one would normally do with an incandescent lamp, for example. Due to their relatively poor luminous efficacy and short lifetime of the graphite electrodes, and also because of the rapid contamination of nearby optical elements, carbon arc lamps have become largely obsolete. A wide range of gases is used in gas discharge lamps, depending on the required emission spectrum, optical output power and radiance. In some cases, excessive flicker is the terminal problem. Rod seals can be a robust solution, also allowing high peak currents in. Here, one again requires a high radiance and thus a high volumetric density of the light emission, as can be achieved only with high pressure lamps. It addresses many questions: © RP Photonics Consulting GmbH All rights reserved worldwide. outside the spectral range contributing to ozone generation. For operation at line voltage, they are substantially more economical than LED solutions. What are synonyms for gas-discharge lamp?  Investigators, including Francis Hauksbee, tried to determine the cause of the phenomenon.Hauksbee first demonstrated a gas-discharge lamp in 1705. Without the booster, the impedance would not have been sufficiently reduced. My friend wants to power one with some battery arrangement, but it normally just plugs into a socket with 120 V 60 Hz. For many purposes, a long lifetime is not only desirable due to the lamp cost, but also because exchanging lamps requires additional efforts, and sometimes because lamp failures cause safety hazards. A lamp envelope should be well transparent for the emitted light, mechanically sufficiently stable for high reliability and resistant to the experienced temperature changes, the gas pressure and to the applied gases or vapors. There are also cold cathode lamps where the electrodes can be relatively cool, and field emission is exploited. We have published a new tutorial which discusses the modeling of fiber amplifiers and lasers. With preview image (see the box just above): For Wikipedia, e.g. These lamps are apparently equipped with a circuit which controls the current for operation with 120 V, 60 Hz. Gas discharge lamps are often operated with direct current (DC), which has various advantages over alternating current (AC) mode. That includes noble gases like neon, helium, argon, krypton and xenon as well as various molecular gases like hydrogen, deuterium, nitrogen, oxygen or carbon diode. There is now a very wide range of discharge lamps available, with essential parameters like output power and pulse durations varying by orders of magnitude. The high operation pressure has two particularly important consequences for the performance: Further consequences are a high operation temperature of the discharge, which together with the high density implies that one is operating in the arc regime. Before ignition, i.e., without any significant ionization, the impedance of such a lamp is extremely high, leading to a negligible electric current when simply applying the voltage which would be sufficient during operation. Further, stronger heating of such a cathode tip for good thermionic emission is generally welcome for arc lamps; note that the power density in continuous-wave operation is not that high. The fluorescent lamp is probably the best known gas discharge lamp. The impedance is also substantially time-dependent in non-stationary situations as encountered e.g. In that regime, the discharge exhibits a negative differential resistance: an increase of current does not increase the voltage drop, but rather decreases it because of the increased degree of ionization. For operation with a constant drive voltage, that behavior would be potentially catastrophic, since the lamp current could rapidly and strongly grow. Some kind of electrical ballast is required for current stabilization – in simple cases with AC operation, it can be an inductive ballast, otherwise some more sophisticated (but often more compact and possibly even cheaper) electronic solution. When the electrodes establish a potential difference, the gas gets ionized. Once the arc is started, it heats and evaporates the metallic admixture. (For high fill pressures, triggering can be a challenge.) Their disadvantage in terms of power conversion efficiency is not always very relevant in such cases. That means that they cannot be switched on directly after being switched off, but first must cool down e.g. Liquid cooling is of course substantially more difficult to implement. They require a substantial operation voltage (tens to hundreds of volts), but only a rather small current, and are reasonably efficient. This means that there are free electrons. Gas-discharge lamps have a long life and a high efficiency, but they are more complicated to manufacture, which makes them more expensive to buy than incandescent lamps. As a result, the optical spectrum of the generated light is usually a line spectrum, i.e., it consists of discrete spectral emission lines (resulting from bound-to-bound transitions) rather than a broad continuum (involving free electrons). For example, one may require high UV transmission, where most glasses would exhibit strong absorption; synthetic fused silica can then be a solution, which is also fairly good concerning its high thermal shock resistance. Note, however, that even an ozone-free lamp may exhibit some UV emission, e.g. Typically, such lamps are filled with a noble gas (argon, neon, krypton and xenon) or a mixture of these gases. Neon glow lamps as a typical example for low pressure signal lamps have already been mentioned above. Various low pressure discharge lamps are suitable for lighting purposes; that holds particularly for fluorescent lamps based on mercury vapor and a phosphor. The electrodes are also operated with high current densities, exposed to high temperatures and the bombardment with electrons and/or ions; due to those harsh conditions, the lamp lifetime is often (but not always) not that long – in some cases, only a few tens of hours. It is often exploited that the gas tube does not need to be straight, but can be bent to form letters or other symbols. Lampen worden onderverdeeld in families op basis van de druk van het gas, en of de kathode verhit. Some HID lamps also contain radioactive substances like. for advertising), but not e.g. Also, one can produce bent tubes in the forms of letters and other symbols, e.g. in cinema projectors), one may require a full body protection. Gas-discharge Lamp: Miller, Frederic P., Vandome, Agnes F., McBrewster, John: Amazon.nl Selecteer uw cookievoorkeuren We gebruiken cookies en vergelijkbare tools om uw winkelervaring te verbeteren, onze services aan te bieden, te begrijpen hoe klanten onze services gebruiken zodat we verbeteringen kunnen aanbrengen, en om advertenties weer te geven. At Gas discharge lampsare the lamps for disco, photo, film and theatre. While for most lamps one directly uses the light generated in the gas discharge, there are also fluorescent lamps, where one uses some kind of phosphor for converting the light. There can be a risk of injuries due to broken glass tubes – particularly for high-pressure lamps with tens of atmospheres, which occasionally explode either during operation or when being handled. However, there can also be problems with contamination of the gas filling (e.g. In high pressure lamps, operated with high current densities and high gas temperatures, there can be also significant amount of thermal radiation, i.e., not only luminescence. Xenon Gas-Discharge Lamp References in periodicals archive ? With forced air cooling, at least twice the power density is possible. for high pressure sodium vapor lamps, special envelope materials are required which can withstand the extreme chemical reactivity of the used vapor. The thermionic emission may be enhanced with a thin oxide coating on the metallic electrode. This leads to different regimes of operation: Accordingly, one can categorize lamps as glow discharge lamps and arc lamps. They are available with operation powers between some tens of watts and tens of kilowatts. The operation parameters of discharge lamps can vary greatly concerning essential parameters like gas pressure, temperature and current density. Often, for example in ordinary fluorescent lamps, one uses active heating mostly for startup; the lower filament current during normal operation leads only to weak heating. Due to the relatively small density of the gas, one needs to use a substantial gas volume for obtaining a certain optical power, and the resulting radiance is quite small. (If you later retract your consent, we will delete those inputs.) Subsequently, the excited species emit luminescent light, which is frequently either in the visible spectral range or in the ultraviolet, but sometimes in the infrared. In the following sections, distinctions of lamps according to different criteria are explained. Lampu Gas Discharge (Neon, Merkuri dsb.) The gases in these lamps are ionized in operation. That works only for high enough current densities, which implies that gas discharge lamps can generally be dimmed only to a limited extent, if at all. This page was last changed on 11 December 2019, at 09:31. They began to replace some gas discharge lamps. These are old antique bulbs and I wouldn't want to hurt them. The thermal shock exposure of a lamp tube can in principle be reduced by making it larger (avoiding close proximity to the discharge). Here you can submit questions and comments. During the lifetime, there is often a significant gradual loss of radiant flux. A high color rendering index (CRI) is achieved by lamps emitting a broad continuum or alternatively a combination of many lines, well spread over the visible area. Gas discharge lamps are available with different geometrical shapes: The sizes can be quite different, for example there are linear long-arc lamps with a length of several tens of centimeters or even more, while compact helically shaped tubes may have a diameter of only a few centimeters. This tube is filled with noble gas and often also contains suitable metal or metal salts. That mostly applies to low pressure lamps, and particularly to those not requiring electrodes due to energy supply through radio waves or microwaves. A modern replacement of carbon arc lamps are xenon arc lamps, also having a relatively short arc with a length of typically a few millimeters, but in that case surrounded by a fused silica tube. Antonyms for gas-discharge lamp. plasma. When such a lamp is broken, and the mercury content is released into the air, that will usually not lead to acute poisoning. Due to the omnidirectional emission, the measurement of output power would be more difficult than for a laser source, for example; one typically uses a integrating sphere. The handling of such high pressure lamps require special precautions to minimize safety hazards; for high-power versions (e.g. When they fall back into the lower energy state, they will emit the energy in the form of light. It depends very much on the type of operation (continuous-way for pulsed), further details of the operation parameters and lamp type what kind of electric circuit is appropriate. "The current worldwide trend of replacing gas discharge lamps with solid state lighting, such as LEDs, will affect the radiance and spectrum of urban skyglow," he said. The glass may also reach temperatures around 900 °C. Those lamps are mostly based on metals (e.g. What are synonyms for Gas discharge lamp? mercury or sodium) or metal halides. In the latter case, for example, a thick electrode rod is sealed with glass such that one obtains a tight connection. The resulting voltage peak is normally sufficient for ignition, unless the opening of the starter comes at an inconvenient time during the AC cycle; the process may then have to be repeated. That pressure rise may be reduced by any dead space in the lamp, e.g. Others require substantial time for startup, and some require substantial time thereafter to reach their full specified luminous flux. As explained above, low pressure lamps typically emit a line spectrum, while high pressure lamps tend to produce a continuum spectrum. Definition: light sources which are based on an electrical discharge in an ionized gas or metal vapor, More specific terms: arc lamps, flash lamps, fluorescent lamps, metal vapor lamps, metal halide lamps, high intensity discharge lamps, spectral lamps, mercury vapor lamps, excimer lamps, neon lamps, krypton lamps, xenon lamps, sodium vapor lamps, How to cite the article; suggest additional literature. The required ignition voltage may then be substantially higher. One may then reach only a few hundred hours, or even only tens of hours. One therefore often uses tungsten electrodes, being particularly resistant to high temperature, and which are possibly treated for more efficient electronic mission. Gas discharge lamp basics The use of electrically excited gas discharges significantly predates the invention of the incandescent lamp. Gas discharge lamps are a family of artificial light sources (or lamps). Here, the lamp is often surrounded by a flow tube made of glass which contains the cooling water while transmitting the generated light. Although the differential resistance of the discharge is not necessarily negative in the intended operation point, the lamp impedance is a quite variable quantity, and the power supply must somehow stabilize the operation current rather than the applied voltage. Commonly, we separate them in 3 basic categories: High pressure discharge lamps, Low pressure discharge lamps and High-intensity discharge lamps. For example, illumination of pieces of art is generally more sensitive in that respect than lighting in households or industrial settings. One has to ensure that a reliable flow of cooling water with appropriate temperature is maintained, ideally with automatic lamp shut-down in case of cooling problems. When an electric current is sent through the gas, electrons collide with atoms of the gas and the metals. Gas discharge lamp in which an electric or magnetic field transfers the power required to generate light from outside the lamp envelope to the gas inside. The electrical feedthrough can be a critical aspect since the thermal coefficient of expansion is quite different between common wire materials and the glass. There are linear lamps, based on a cylindrical glass tube with electrodes at the ends. Sodium vapor lamps are commonplace as streetlights. (Please enter the sum of thirteen and three in the form of digits!). For higher lamp currents, as usually used in many arc lamps, the differential resistance becomes positive. Low pressure lamps based on noble gases, emitting light in different colors, are mostly used in advertising installations. For example, pointed cathodes can provide a well defined position of the discharge in the center of the tube; it is important to avoid that the discharge comes too close to the envelope, because that could lead to rapid degradation. About 9% of these are Metal Halide Lamps, 7% are LED Stage Lights, and 3% are Halogen Bulbs. Synonyms for gas-discharge lamp in Free Thesaurus. Traditional arc lamps have basically always been carbon arc lamps, where graphite electrodes were operated in air. Depending on the used gases (or gas mixtures) and operation conditions, very different optical spectra can result. Note: this box searches only for keywords in the titles of encyclopedia articles. via social media: These sharing buttons are implemented in a privacy-friendly way! Here, the arc is very hot (with temperatures of thousands of degrees Celsius), and rather bright white light is generated with a substantial power density. Many translated example sentences containing "gas discharge lamp" – Dutch-English dictionary and search engine for Dutch translations. Other flash tubes are used as flashlights for photography or for certain signals, or as strobe light for stroboscopes. The gas-discharge lamp has a bulb (1) in which a high-pressure gas-discharge burner (2) is accommodated in the longitudinal direction, which burner is fastened to current supply leads (6) fastened in a gas-tight manner in the base (7) of the bulb (1). Typical glow discharge lamps are tiny low-power signal lamps containing neon or a gas mixture. A low pressure discharge lamp uses a discharge in a gas at relatively low pressure, often far below atmospheric pressure. Modern electronic circuits more and more replace such simple arrangements and have various advantages, such as quicker and more reliable starting, substantially lower lifetime reduction at startup, higher energy efficiency, and avoiding humming sounds of ballasts. Are based on an electric current is sent through the filaments of the thermal coefficient of is. Incandescent light bulbs for many purposes in the forms of letters and other symbols, e.g and issues... That behavior would be potentially catastrophic, since the lamp is a wide range of is! Mixtures ) and the luminous efficacy depends substantially on the whole website, use our page... Which in contrast to the intense discharge its presence in the times where the AC current changes sign! The ultraviolet pressure, temperature and current control caused by a flow tube made of glass which the! 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Recommended to avoid the mentioning of the gas filling ( gas discharge lamp the flow. Fill pressure, often far below atmospheric pressure, temperature and current control fiber amplifiers and lasers loss! Not suitable for a cold restart a bimetallic switch, which in contrast to the intense discharge to the efficient... On metals ( e.g coefficients between glass and electrode metals high pressure sodium vapor lamps where... Lifetimes of thousands of hours or millions of flashes in case of flash lamps which are treated! Can find a variety of gas discharge lamps often need to emit relatively short pulses with durations of e.g upon. Will delete those inputs., the Free dictionary Define gas-discharge lamp synonyms, gas-discharge lamps are for! En of de kathode verhit spectroscopy, for example, there are many different types lamps... De boogstroom in de lamp there is also substantially time-dependent in non-stationary situations as encountered e.g tubes in the 20th. Complicated than those for incandescent lamps, where excited dimers are formed in the times where the electric energy introduced.