Fluorescent lamps are a special class of gas discharge lamps where the electric current produces mostly invisible uv light which is turned into visible light by a special phosphor coating on the interior of the tube. The uk is adopting the ewcs european waste catalogue which will classify fluorescent lamps as hazardous waste. Gas discharge lamps fluorescent tubes, metal halide, sodium etc lamp disposal and recycling. Neon orange hydrogen red helium yellow carbon dioxide white mercury blue neon glow lamp electronic indicator. The character of the gas discharge critically depends on the frequency or modulation of the current. Typically, such lamps use a noble gas argon, neon, krypton and xenon or a mixture of these gases. At either end a small tungsten filament was connected to. A fluorescent lamp is a low weight mercury vapour lamp that uses fluorescence to deliver visible light. Air is the cheapest and inexhaustible insulation material.
Request pdf lowpressure gas discharge lamps this chapter provides an overview of the current technology in lowpressure discharge lamps. This circuit senses the primary current of the main transformer. Publishers pdf, also known as version of record includes final page, issue and. Gases are normally poor conductors, especially at atmospheric and higher pressures, but application of suitable voltage, called the ignition voltage, across the two electrodes can result in a discharge through the gas, which is. Us6414448b1 electronic ballast for a gas discharge lamp. Typically, such lamps use a noble gas argon, neon, krypton, and xenon or a mixture of these gases. Lamp anatomy how they produce colors how they produce white light. The fluorescent lamp is perhaps the best known gas discharge lamp. Breakdown and flashover are collectively referred as discharge. S0963025200155926 introduction to gas discharges n st j braithwaite the open university, oxford research unit, foxcombe hall, boars hill, oxford ox1 5hr. Return to updates gas discharge lamps a better theory by miles mathis first published august 5, 2015 this paper is one of the fruits of my third conference, which happened a couple of weeks ago. Aug 20, 2016 a fluorescent lamp tube is filled with a gas containing low pressure mercury vapor and argon, xenon, neon, or krypton. Neon lamps are gas discharge lamps that contain neon gas at a low pressure enveloped in a glass capsule.
A flicker light bulb, flicker flame light bulb or flicker glow lamp is a gas discharge lamp which produces light by ionizing a gas, usually neon mixed with helium and a small amount of nitrogen gas, by an electric current passing through two flame shaped electrode screens coated with partially decomposed barium azide. The french astronomer jean picard observed 1675 a faint glow in a mercurybarometer tube when it was agitated, but the cause of the glow. Highintensity 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. Definition of a plasma mixture of electrons, ions and neutral particles in different excited states and with strong. An electronic ballast for a gas discharge lamp as claimed in claim 1, in which the high frequency inverter has two switches being switched on and off during each respective cycle to drive current through the inductor and to the gas discharge lamp. Gas discharge lamps have a high light output per watt and have a long live expectancy. Request pdf thomson scattering on a lowpressure, inductivelycoupled gas discharge lamp excitation and light production processes in gas discharge lamps are the result of inelastic collisions. Gas discharge lamp basics 3 low pressure fluorescent lamp current flows through plasma between electrodes must be ac or mercury migrates to one end plasma emits mostly uv radiation uv excites coating to fluoresce and produce visible light heated electrodes improve lamp life and lower strike voltage argon and mercury vapor. Gas discharge plasmas and their applications sciencedirect. C when the neon lamp discharge changes from a glow to.
Bourns part numbering for discrete components and 5pin modules and the general operation of a gdt. The discharge gas is argon for the ql lamp, and krypton for the genura lamp. Return to updates gas discharge lamps miles mathis. Gas discharge lamps are a family of artificial light sources that generate light by sending an. When they fall back into the lower energy state, they will emit the energy in the form of light.
Cathoderay or electron stream lamps, in particular flat panel electron emission lamps. Once the discharge is extinguished, it can recover insulation performance, so the gas insulation has a kind of selfrecovery insulation property. When an electric current is sent through the gas, electrons collide with atoms of the gas and the metals. The inner surface of the lamp is coated with a fluorescent and often slightly phosphorescent coating made of varying blends of metallic and rareearth. An overview is given of transport reactions and corrosion phenomena in metal halide gas discharge lamps filled with a mixture of alkali halides with scandium or rareearth iodides. Explain the basic structure of an atom and relate it to the color of light produced by discharge lamps. Introduction gas discharge lamp basics the use of electrically excited gas discharges significantly predates the invention of the incandescent lamp. The ql lamp has an additional phosphor layer at the surface of the cavity to enhance the conversion efficiency of the uv to the visible light. At any lamp we help you find the right gas discharge lamp. Provide a basic design for a discharge lamp and explain the function of the different components. Company confidential gas discharge lamp basics 3 low pressure fluorescent lamp current flows through plasma between electrodes must be ac or mercury migrates to one end plasma emits mostly uv radiation uv excites coating to fluoresce and produce visible light heated electrodes improve lamp life and lower strike voltage argon and mercury vapor. When the electrodes establish a potential difference, the gas gets ionized.
There are many different types of lamps that operate under this principle. Comparison between discharge and led lighting fixtures. A protection circuit for the power supply of a gas. Explain why discharge lamps emit only certain colors. Electric discharge tubes or discharge lamps sparkgaps h01t. First principles of a gas discharge tube gdt primary protector. A neon lamp is made of a discharge tube filled with 95. This will mean that some reach a higher energy state. Fluorescent lamps fl, contain mercury, a highly efficient emitter of uv radi ation, which is then converted to visible radiation by a phosphor coating on the lamp. We offer you gas discharge lamps at low prices with a fast delivery.
This tube is filled with noble gas and often also contains suitable metal or metal salts. How gas discharging lamps work cold cathode ccfl and hot. Fluorescent lamp and working principle of fluorescent lamp. Most lamps are filled with additional materials, like mercury, sodium, andor metal. In gas discharge lamps, light is generated primarily by an electrically excited plasma.
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. Electronic operation and control of highintensity gas discharge lamps. The passage of an electric current through this gas vapour produces light or ultraviolet radiation. A hydrogen discharge lamp has a glass lamp enclosure formed with a radiationemitting window and receiving a body of a zirconiumcobalt alloy forming in part a hydride which constitutes a reservoir for hydrogen or deuterium and enabling controlled liberation of the hydrogen or deuterium from the reservoir. A discharge lamp consists essentially of a tube of glass, quartz or other suitable material, containing a gas and, in most cases, a metal vapour. Gasdischarge lamp article about gasdischarge lamp by the. Gas discharge lamps are a family of artificial light sources that generate light by sending an electric discharge through an ionized gas, a plasma. Gas discharge lamps are a family of artificial light sources that generate light by sending an electrical discharge through an ionized gas. Electric discharge tubes or discharge lamps sparkgaps. Chapter low pressure discharge lamps slide 7 incoherent light sources prof. High pressure discharge lamps, low pressure discharge lamps and highintensity discharge lamps. Discharge lamps 10 neon discharge lamps neon lamp metal electrodes inject free charges into dilute neon plasma formsa vapor of charged particles electric field causes current to flow in the plasma current is mostly electrons streaming toward positive electrons often collide violently with neon atoms discharge lamps 11. Design a discharge lamp to emit any desired spectrum of colors. Make sure to use the right socket when changing your gas discharge lamp.
An electric current in the gas energizes mercury vapor which delivers ultraviolet radiation through discharge process and the ultraviolet radiation causes the phosphor coating of the lamp inner wall to radiate visible light. Lowpressure gas discharge lamps request pdf researchgate. Gasdischarge lamp project gutenberg selfpublishing. Some include additional substances, like mercury, sodium, and metal halides, which are vaporized during startup to become part of the gas mixture. Transport processes in metal halide gas discharge lamps. Thomson scattering on a lowpressure, inductivelycoupled. The colors of gasdischarge lamps vary widely depending on the identity of the gas and the construction of the lamp. The fluorescent discharge lamp was introduced in britain in 1940, but was available earlier in america. The basic principle of a gaseous discharge lamp is illustrated in fig. Gas discharge tubes are extensively used for the protection of telecommunications plant and equipment against overvoltages caused by lightning, power switching and fault conditions. Physics labs of yesteryear as well as today have use of a variety of gas filled tubes used for. Mar 15, 2020 a fluorescent lamp is a low weight mercury vapour lamp that uses fluorescence to deliver visible light.
A gas discharge lamp is a light source that generates light by creating an electrical discharge through an ionized gas. World heritage encyclopedia, the aggregation of the largest online encyclopedias. The gas discharge will only cause a temporary loss of the insulation. Sams and dons dlamp faq gas discharge lamps, ballasts, and. The fluorescent lamp is probably the best known gas discharge lamp. To solve this problem, a simple protection circuit for the power supply of a gas discharge lamp is proposed in this paper. Gas discharge lamp simple english wikipedia, the free. Besides the rare gas, mercury is also present, which is necessary in all fluorescence lamps. The ionization degree may vary anywhere from 100% to 10 4 10 6 i.
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