Those engineers applying such lamps simply need to work based on their experience how much laser output can be achieved with a certain type of lamp driven with a certain electrical power or pulse energy. Note, however, that even an ozone-free lamp may exhibit some UV emission, e.g. "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. For example, one may produce a porous tungsten matrix and impregnate it with barium or some other material with low work function. 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. These are old antique bulbs and I wouldn't want to hurt them. See the article on fluorescent lamps for more details. These lamps are apparently equipped with a circuit which controls the current for operation with 120 V, 60 Hz. Although the optical output power (radiant flux) and the radiance or a lamp would have some relevance for various applications, these are rarely specified. Various details of electrodes can have a substantial impact on the lamp performance and lifetime. Please do not enter personal data here; we would otherwise delete it soon. Gas discharge lamps. Therefore, they are often based on simple gases like xenon. 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. Note that the emission spectrum can also substantially depend on the operation conditions, particularly on the applied current density and the resulting plasma temperature. In some cases, for example for some lamp-pumped lasers, the whole lamp is surrounded by deionized cooling water (having a low electrical conductivity). The electrodes may receive some cooling through thermal conduction through the wires. Some of them have already been used from the second half of the 19th century on, while others were invented much later. (Please enter the sum of thirteen and three in the form of digits!). It is of course not easy to develop a reliable lamp construction, ensuring good heat flow while avoiding any leaks and insulation issues. The discharge is usually in the glow discharge regime. It heats up a bimetallic switch, which eventually short-circuits it. I can of course not give a guarantee, but I would expect such glow lamps not to be particularly sensitive to deviations from the ideal line voltage. They come in three different forms: high pressure discharge, low pressure discharge and high-intensity discharge. Note, however, that the impedance parameter K0 cannot be considered as a device constant. The naming is sometimes misleading; for example, some cars are said to be equipped with xenon lamps, although in reality they are actually metal halide lamps also containing some xenon as starter gas, which also provides some light output before the full luminous flux from the halides is reached. Note that it is common to say that quartz envelopes are used, but this is misleading, since what is meant is then fused silica, also called fused quartz, which is silica glass rather than a crystalline material like natural quartz. With preview image (see the box just above): For Wikipedia, e.g. Early in the 21st century, light-emitting diodes improved, with even higher efficiency. 1 synonym for gas-discharge lamp: electric-discharge lamp. 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. For conducting an electric current, the gas must be ionized (at least to some degree, normally below 1%). There is also a common tendency to avoid the mentioning of the poisonous mercury. Typically, such lamps are filled with a noble gas (argon, neon, krypton and xenon) or a mixture of these gases. 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. In the context of lighting, the quality of color rendering is often of interest. For startup, one generally requires a high-voltage trigger pulse, and sometimes an additional booster pulse. The required ignition voltage and operation voltage depend on the gas pressure and on the type of gas. Essentially, the operation principal of any gas discharge lamp involves that gas atoms or molecules are transferred into excited electronic states by impinging electrons, or alternatively by energy transfers from other gas atoms, ions or molecules. Gas discharge lamps are light sources which are based on an electric discharge in an ionized gas or metal vapor. In the latter case, for example, a thick electrode rod is sealed with glass such that one obtains a tight connection. Due to the very limited available time for starting the discharge, flash lamps cannot utilize materials which would first have to be evaporated. Those lamps are mostly based on metals (e.g. In earlier times, such lamps were also used in the form of alphanumerical displays, before those were largely replaced with devices based on light-emitting diodes. The operation temperature of the gas (e.g. At the end of durability (strong colour changes, difficult to start up or on/off), replace the lamp on time to prevent defects to the ballast. 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. Names for specific types of lamps can refer to different such aspects; for example, a neon lamp indicates that a discharge in neon gas is used (possibly with added other gases), a glow lamp is recognized to work in the glow discharge regime, a high pressure lamp obviously uses a relatively high gas pressure, and a flash lamp is used for producing light pulses. Cathodes should have a low work function (i.e., easily emit electrons) for minimizing the required voltage and maximizing the efficiency. They are used in electrical switches, for example, for indicating the “on” state, or elsewhere just to indicate that line voltage is available. There are many different types of lamps that operate under this principle. 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. While that effect can be minimal for modern fluorescent lamps, allowing many thousands of switching cycles during the lifetime, it can be serious for metal halide lamps, for example. The lamp voltage may grow in proportion to the square root of the current; that frequently observed behavior led to the definition of the impedance parameter K0, which determines the lamp impedance according to R = K0 I−1/2. However, there are important exceptions, where AC operation is possible and has the advantage of lower complexity of the electrical drive circuit. History. The excitation current through the gas is in most cases applied with two electrodes, which are typically placed at two opposite ends of a glass tube containing the gas. Many lamps can simply be operated in air, with no special cooling of the lamp envelope. High pressure lamps (e.g. are found in the RP Photonics Buyer's Guide. Also, one avoids the risk of using the ionization in the times where the AC current changes its sign. your website, social media, a discussion forum, Wikipedia), you can get the required code here. That mostly applies to low pressure lamps, and particularly to those not requiring electrodes due to energy supply through radio waves or microwaves. These lamps contain noble gases like: argon, neon, krypton and xenon. When starting with a low lamp current after triggering the discharge, the impedance of the plasma rapidly decreases with increasing current, because that increases the degree of ionization. The voltage drop is then U = R I = K0 I1/2. In other cases, one uses fused silica (“quartz”) with some dopants for introducing UV absorption, because intense ultraviolet light would be detrimental; it could damage parts of an application setup (e.g. Unfortunately, I do not know what kind of circuits they used. However, the term arc lamp is also often used for lamps which actually operate in the glow discharge regime; arc is then meant to emphasize continuous operation in contrast to pulsed operation with a spark; details of the physics of the discharge are then largely ignored. Xenon Gas-Discharge Lamp References in periodicals archive ? A gas discharge lamp consists of a transparent gas discharge enclosure containing a small quantity of gas or vapour at a low pressure and two electrodes provided for connecting the lamp to the supply mains. several or even tens of atmospheres. Commonly, we separate them in 3 basic categories: High pressure discharge lamps, Low pressure discharge lamps and High-intensity discharge lamps. Nevertheless, such mercury exposure should be avoided if at all possible. Discharge lamps often require quite high operation voltages, which may cause severe electric shocks if someone touches a wire. In other cases, one uses much higher pressures, e.g. 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. Define gas-discharge lamp. For example, some flash lamps are used for pumping of pulsed (free-running or Q-switched) solid-state lasers (→ lamp-pumped lasers). What are synonyms for Gas discharge lamp? gas-discharge lamp synonyms, gas-discharge lamp pronunciation, gas-discharge lamp translation, English dictionary definition of gas-discharge lamp. 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. 1 synonym for gas-discharge lamp: electric-discharge lamp. Different kinds of seals have been developed, in particular solder seals, ribbon seals and rod seals. Some lamps emit substantial amounts of ultraviolet light, which can be detrimental in different ways, particularly for exposed skin and eyes, sometimes also through the generation of poisonous ozone in air. 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. 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. Their disadvantage in terms of power conversion efficiency is not always very relevant in such cases. The very effective heat removal then allows for operation with substantially higher heat loads, e.g. First of all, what is a gas discharge lamp? at a few hundred millibars, which is however quite high compared with low pressure lamps. Physics labs of yesteryear as well as today have use of a variety of gas filled tubes used for numerous purposes involving light generation including spectroscopy, materials analysis, studies of gas dynamics, and laser pumping. High-intensity discharge lamps (HID lamps) are a type of electrical gas-discharge lamp which produces light by means of an electric arc between tungsten electrodes housed inside a translucent or transparent fused quartz or fused alumina arc tube. Some constructions involve water cooling for the electrodes, or at least the anode, which often gets hotter. In contrast to a typical gas discharge lamp that uses internal electrodes connected to the power supply by conductors that pass through the lamp envelope. That works particularly for flash lamps which are operated with low repetition rates. Unfortunately, long lamp lifetimes are much more difficult to achieve for lamps where a high power density is required, e.g. The envelope is usually realized as a sealed glass container (often in the form of a cylindrical glass tube with a bore diameter of a few millimeters) which is penetrated by the electrode wires. Note: the article keyword search field and some other of the site's functionality would require Javascript, which however is turned off in your browser. Compared with low pressure lamps, they exhibit a smoother optical spectrum, but still basically a yellow appearance, which is sometimes accepted for industrial lighting and plant growth but would normally not be considered as suitable for indoor lighting. For operation with a constant drive voltage, that behavior would be potentially catastrophic, since the lamp current could rapidly and strongly grow. The quasi-monochromatic emission of some low pressure lamps makes them useful as spectral lamps for applications in spectroscopy, for example. That is the case for some high-intensity projector lamps, for example. That pressure rise may be reduced by any dead space in the lamp, e.g. Encyclopedia article about gas-discharge lamp by The Free Dictionary xenon) one obtains a wide range of lines throughout the visible region and including the ultraviolet. Many translated example sentences containing "gas discharge lamp" – Dutch-English dictionary and search engine for Dutch translations. Such lamps belong to the category of high pressure discharge lamps, as further discussed below. Some important aspects are briefly explained in the following: Generally, power supplies for gas discharge lamps are somewhat more complicated than those for incandescent lamps, for example: There is a wide range of gas discharge lamps, which can greatly differ in various aspects like the used gas, the gas pressure, the type of electric discharge, the operation mode (continuous or pulsed), and details of the electrodes. 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. Flash lamps are often based on noble gases like neon, argon, krypton and xenon, while arc lamps can also involve metals and metal halides. xenon. While some gas discharge lamps are specifically made for emitting mostly ultraviolet light, others produce some unwanted ultraviolet light in addition to the actually used visible light. However, there can also be problems with contamination of the gas filling (e.g. An additional housing may be used during transport (before and after actual use) and can protect against injury by flying debris, but not necessarily against mercury contamination. There are also cold cathode lamps where the electrodes can be relatively cool, and field emission is exploited. The technology has in some areas been substantially developed further in recent decades. Lamp life is often limited by the degradation of electrodes and related problems, such as the deposition of electrode material on the inner side of the glass envelope. In particular, each electrode has a well defined function (cathode or anode) and can be optimized accordingly. for a couple of minutes. Discharge lamp definition is - an electric lamp in which an enclosed gas or vapor glows or causes a phosphor coating on the lamp's inner surface to glow. Also, one can produce bent tubes in the forms of letters and other symbols, e.g. in terms of optical spectrum, luminous efficacy, radiance and ease of ignition. Although lamp-pump lasers have been replaced with diode-pumped lasers in many areas, they remain superior, at least in terms of cost, particularly for some applications requiring high pulse energies in combination with moderate pulse repetition rates. In other cases, the electrodes are filaments, somewhat similar to those as used in incandescent lamps; they can be heated with an electrical current to the required temperature. For some applications, bent shapes are required, e.g. Sodium vapor lamps are commonplace as streetlights. 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. With modern electronics, lamp performance can be substantially enhanced. Various low pressure discharge lamps are suitable for lighting purposes; that holds particularly for fluorescent lamps based on mercury vapor and a phosphor. In some cases, the luminous efficacy depends substantially on the ambient temperature. Due to the higher rate of collision processes, which lead to, Due to the resulting high density of gas atoms, ions or molecules, one can obtain a substantially higher light output per unit volume, and accordingly a much higher. Other flash tubes are used as flashlights for photography or for certain signals, or as strobe light for stroboscopes. In some cases, e.g. Often it is recommended to avoid frequent switching, because that can degrade their lifetime. Looking for information about power supply options for an Aerolux glow lamp. They do not require a special starting circuit, but only a simple series resistor, which is sometimes integrated into the lamp. 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. Some of them contain poisonous materials such as mercury. The water flow should usually be directed from the anode to the cathode, since the heat load on the anode is substantially larger. The continuous emission often leads to the naming as arc lamps even if the physical operation parameters actually indicate the glow discharge regime. Here you can submit questions and comments. That may not only constitute a loss of energy, but also have negative side effects concerning human skin and eyes. Some lamps are optimized for particularly high volumetric emission densities; they are called high-intensity discharge lamps (HID lamps). 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. Some gas discharge lamps (hot cathode lamps) require high temperatures of the electrodes, at least of the cathode (for operation with DC current), because only then one obtains sufficiently strong thermionic emission of electrons into the gas. Therefore, lamp lifetimes of many thousands of hours are often achieved. Depending on the used gases (or gas mixtures) and operation conditions, very different optical spectra can result. When such a lamp is broken, and the mercury content is released into the air, that will usually not lead to acute poisoning. For relatively low average power densities, simple convection cooling by ambient air is normally sufficient. The luminous efficacy (specified in lm/W) depends very much on the type of lamp, mostly on the used gas, but also on the operation regime. With forced air cooling, one can accelerate the heat transfer. Essentially, the issue must be of sufficiently broad interest. Gas-discharge lamps are a family of artificial light sources that generate light by sending an electrical discharge through an ionized gas. Without the booster, the impedance would not have been sufficiently reduced. 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. mercury or sodium) or metal halides. Electrode shapes can be quite important. For example, there are translucent aluminum oxide ceramic envelopes. There is a wide range of different sockets, adapted to different operation voltages and powers. While that approach normally leads to higher construction cost, it usually allows for particularly long lamp lifetimes, since the typical degradation at the electrodes is avoided. Rod seals can be a robust solution, also allowing high peak currents in. The operation parameters of discharge lamps can vary greatly concerning essential parameters like gas pressure, temperature and current density. The fluorescent lamp is probably the best known gas discharge lamp. When an electric current is sent through the gas, electrons collide with atoms of the gas and the metals. There are also electrode-less lamps, where the electric energy is introduced in other ways, typically with a radio frequency or microwave field. Low pressure lamps based on noble gases, emitting light in different colors, are mostly used in advertising installations. for projection displays or search lamps, where a well directed light beam needs to be generated. Usually, flash lamps have a relatively large emitting volume in order to achieve sufficiently high pulse energies. The impedance is also substantially time-dependent in non-stationary situations as encountered e.g. 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. Particularly some low pressure lamps, emitting only a few such lines, are relatively poor in terms of color rendering. 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. by degrading electrodes. See also: arc lamps, flash lamps, metal vapor lamps, metal halide lamps, high intensity discharge lamps, xenon lamps, spectral lamps, fluorescent lamps, signal lamps, lamp power supplies, color rendering indexand other articles in the category non-laser light sources. for laser pumping, usually require liquid cooling, in most cases with a turbulent flow of demineralized water, e.g. The power density is also quite high; an electrical power between some tens of watts and many kilowatts is converted in a relatively small volume, leading to a very high operation temperature of the arc and to emission with a relatively high radiance – suitable for high-power projection displays (in cinemas and beamers) and directed search lights, for example. with krypton or xenon at multiple atmospheres) are also used for pumping of continuous-wave or pulsed (free-running or Q-switched) solid-state lasers (→ lamp-pumped lasers), where the light output of low pressure lamps would normally be insufficient. There can be substantial environmental pollution associated with electricity generation. However, you could use some DC-to-AC converter, producing 120 V at 60 Hz. Italian: All italiano: Luci al neon e altre lampade a scarica : Japanese: All 日本語: ネオンサインと放電ランプ: Kazakh: All Kazakh: Неон жарықтар және басқалары разрядтық жарықтар: Korean That is most problematic for inefficient lamps, but gas discharge lamps actually often belong to the most efficient light sources available. Therefore, it is sometimes preferable to use ozone-free lamps, where the UV emission is minimized e.g. plastics, seals and laser crystals) and could also cause disturbing ozone generation from ambient oxygen. Synonyms for gas-discharge lamp in Free Thesaurus. In that way, one can produce “ozone-free” lamps. 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. 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). Depending on the type of lamp, the lifetime is more or less reduced by every restart. Others require substantial time for startup, and some require substantial time thereafter to reach their full specified luminous flux. For full-text searches on the whole website, use our search page. RF interference is another matter – it just depends on the used device. In nearly all cases, a gas discharge lamp requires a kind of transparent enclosure for keeping the gas separated from the ambient atmosphere; the only notable exception is the traditional carbon arc lamp, working with air at atmospheric pressure. It must be ensured that the electrical feedthroughs do not lead to any leaks. Special care is necessary for cooled electrodes, avoiding any insulation problems despite the applied high voltages. Gas discharge lamps are a family of artificial light sources (or lamps).These lamps produce light by sending electricity through an ionized gas.Most of these lamps use a noble gas, or a combination of noble gases, but they often contain other materials, such as mercury, sodium or metal halides.The gases in these lamps are ionized in operation. Envelopes for low pressure lamps often have a simple cylindrical form. titanium oxide or cerium oxide) in the tube glass, or by operating the lamp in a nitrogen atmosphere, because ozone can be generated only by irradiating oxygen. in cinema projectors), one may require a full body protection. a U shape, a near circle or a helical shape. The French astronomer Jean Picard observed (1675) a faint glow in a mercury-barometer tube when it was agitated, but the cause of the glow (static electricity) was not then understood. Some tiny low pressure cold cathode neon lamps, also called neon glow lamps, are still widely used for signal applications. 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. mercury, some halides and xenon) and the electrodes is generally quite high. There are also lasers exploiting gain (light amplification) in gas discharges – for example, helium–neon lasers, CO2 lasers and argon ion lasers. Upon startup, that must be achieved by applying an electrical voltage which is sufficiently high for ignition, often using an auxiliary electrical circuit. 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. We have published a new tutorial which discusses the modeling of fiber amplifiers and lasers. due to a too high ignition voltage), or that it produces insufficient light output. When the electrodes establish a potential difference, the gas gets ionized. For example, that is the case for lamps involving mercury discharges, because the mercury pressure is temperature-dependent. 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. 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. Gas Discharge Lamps. There are linear lamps, based on a cylindrical glass tube with electrodes at the ends.