NationMaster - Encyclopedia: Fluorescent lighting

A fluorescent lamp is a type of lamp that uses electricity to excite mercury vapor in argon or neon gas, producing short-wave ultraviolet light. This light then causes a phosphor to fluoresce, producing visible light. Download high resolution version (1024x768, 34 KB)Fluorescent lamp Light Bulb by thesaint: A fluorescent light bulb Source: Stock. ... Download high resolution version (1024x768, 34 KB)Fluorescent lamp Light Bulb by thesaint: A fluorescent light bulb Source: Stock. ... Ballast may mean: track ballast: gravel or cinders forming the railroad or railway track-bed on which sleepers (ties) and track is laid, for proper drainage ships ballast: water, sand, rocks, or bricks used to weight a ship down when it has very little cargo (though water may contain... Electricity is a property of certain subatomic particles (e. ... General Name, Symbol, Number Mercury, Hg, 80 Chemical series transition metals Group, Period, Block 12 (IIB), 6, d Density, Hardness liquid 13,579 kg/m3 solid @ −39 °C 15,600 kg/m3 1. ... Vapor (US English) or vapour (British English) is the gaseous state of matter. ... General Name, Symbol, Number argon, Ar, 18 Chemical series noble gases Group, Period, Block 18 (VIIIA), 3, p Density, Hardness 1. ... General Name, Symbol, Number neon, Ne, 10 Chemical series noble gases Group, Period, Block 18, 2, p Appearance colorless Atomic mass 20. ... Ultraviolet (UV) radiation is electromagnetic radiation of a wavelength shorter than that of the visible region, but longer than that of soft X-rays. ... A phosphor is a substance that can exhibit the phenomenon of fluorescence (glowing during absorption of radiation of another kind) or phosphorescence (sustained glowing without further stimulus). ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized cadmium selenide (CdSe) quantum dots. ... Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye, or in a more general sense, any electromagnetic radiation in the range from infrared to ultraviolet. ...

Fluorescent lamps are more efficient than incandescent light bulbs of an equivalent brightness. This is because more of the energy input is converted to usable light and less is converted to heat (allowing fluorescent lamps to run cooler). They also have a longer lamp life. Efficiency is the capability of acting or producing effectively with a minimum of waste, expense, or unnecessary effort. ... The incandescent light bulb (archaically known as the electric lamp) uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation or incandescence). ... Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye, or in a more general sense, any electromagnetic radiation in the range from infrared to ultraviolet. ... A red-hot iron rod cooling after being worked by a blacksmith. ...

However, unlike incandescent lamps, fluorescent lamps always require auxiliary equipment (a ballast). Ballast may mean: track ballast: gravel or cinders forming the railroad or railway track-bed on which sleepers (ties) and track is laid, for proper drainage ships ballast: water, sand, rocks, or bricks used to weight a ship down when it has very little cargo (though water may contain...

History

The earliest ancestor of the fluorescent lamp is probably the device by Heinrich Geissler who obtained in 1856 a bluish glow from a gas sealed in a tube, excited with an induction coil. Though he is remembered as a physicist, it is interesting to note that Geissler was educated as a glassblower, which was certainly of some value for this earliest realization. Heinrich Geissler (May 26, 1814 - January 24, 1879) was a German physicist. ... 1856 was a leap year starting on Tuesday (see link for calendar). ... A glass pipe made by lampworking Hand-blown glass beads and pendants Glassblowing is the process of forming glass into useful shapes while the glass is in a molten, semi-liquid state. ...

In 1857, French physicist Henri Becquerel had the idea of a tube encapsulating fluorescent gas while leading investigations on fluorescence, phosphorescence and radioactivity. 1857 was a common year starting on Thursday (see link for calendar). ... Henri Becquerel Antoine Henri Becquerel (December 15, 1852 – August 25, 1908) was a French physicist, Nobel laureate, and one of the discoverers of radioactivity. ... Phosphorescence is the result of a radiative (light emitting) transition involving a change in the spin multiplicity of (in most cases) a molecule from excited state singlet to excited state triplet. ... Radioactive decay is the set of various processes by which unstable atomic nuclei (nuclides) emit subatomic particles. ...

At the 1893 World's Fair, the World Columbian Exposition in Chicago, Illinois, Nikola Tesla's fluorescent lights were displayed. 1893 was a common year starting on Sunday (see link for calendar). ... Worlds Fair is the generic name for various large expositions held since the mid 19th century. ... World Columbian Exposition, Chicago, 1893 The World Columbian Exposition (also called The Chicago Worlds Fair), a Worlds fair, was held in Chicago in 1893 to celebrate the 400th anniversary of Christopher Columbuss discovery of the New World. ... Chicago (officially named the City of Chicago) is the third largest city in the United States (after New York City and Los Angeles), with an official population of 2,896,016, as of the 2000 census. ... State nickname: Land of Lincoln, The Prairie State Other U.S. States Capital Springfield Largest city Chicago Governor Rod Blagojevich Official languages English Area 149,998 km² (25th) - Land 143,968 km² - Water 6,030 km² (4. ... Nikola Tesla (baptismal name: Николай) was an inventor, physicist, mechanical engineer, and electrical engineer. ...

In 1894, D. McFarlane Moore created the Moore lamp, a commercial gas discharge lamp meant to compete with the incandescent light bulb of his former boss Thomas Edison. The gases used were nitrogen and carbon dioxide emitting respectively pink and white light, and had moderate success. 1894 was a common year starting on Monday (see link for calendar). ... Daniel McFarlane Moore was an American inventor who created in 1894 gas discharge lamps, known as Moore lamps, in much respects the precursor of today fluorescent lamps. ... The 300,000-watt Plasma Arc Lamp in the Infrared Processing Center (IPC) at Oak Ridge National Laboratory An arc lamp is a device that produces light by the sparking (or arcing, from voltaic arc or electric arc) of a high current between two carbon rod electrodes. ... The incandescent light bulb (archaically known as the electric lamp) uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation or incandescence). ... Thomas Alva Edison Thomas Alva Edison (February 11, 1847 – October 18, 1931) was an American inventor and businessman who developed many important devices. ... General Name, Symbol, Number Nitrogen, N, 7 Chemical series nonmetals Group, Period, Block 15 (VA), 2, p Density 1. ... Carbon dioxide is an atmospheric gas composed of one carbon and two oxygen atoms. ...

In 1901, Peter Cooper Hewitt demonstrated the mercury-vapor lamp, which was emitting in the blue-green spectrum and thus was unfit for most practical purposes. It was, however, very close to the modern design, and had some applications in photography where color was not yet an issue, thanks to its much higher efficiency than incandescent lamps. 1901 was a common year starting on Tuesday (see link for calendar). ... Peter Cooper Hewitt (May 5, 1861 - August 25, 1921) was an American electrical engineer, who demonstrated the mercury-vapor lamp for which he deposited a patent. ...

It remained to Edmund Germer and coworkers to propose in 1926 to coat the tube with fluorescent powder which converts ultraviolet light emitted by a rare gas into better spectrally distributed light (also bringing up high pressure of the gas at the same time). Germer is today recognized as the inventor of fluorescent lamp. Edmund Germer (August 24, 1901 - August 10, 1987) was a German inventor granted as the father of the fluorescent lamp for which he deposited U.S. Patent No 2,182,732 in 1926 with Friedrich Meyer and Hans J. Spanner. ... 1926 was a common year starting on Friday (link will take you to calendar). ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized cadmium selenide (CdSe) quantum dots. ... Ultraviolet (UV) radiation is electromagnetic radiation of a wavelength shorter than that of the visible region, but longer than that of soft X-rays. ...

General Electric later bought Germer's patent and under the impulsion of George Inman brought the fluorescent lamp to wide commercial use in 1938. The General Electric Company, or GE, (NYSE: GE) is a multinational technology and services company. ... 1938 was a common year starting on Saturday (link will take you to calendar). ...

Principle

A fluorescent light bulb is filled with a gas containing argon and mercury vapor, sometimes referred to as plasma when electrified. The inner surface of the bulb is coated with a fluorescent paint made of varying blends of metallic and rare-earth phosphor salts. The bulb's cathode emits electrons which ignite the plasma under the influence of the voltage applied to the light bulb. Then plasma electrons bombard the mercury vapor causing it to emit ultraviolet (UV) light at a wavelength of 254 nm. The UV light is absorbed by the bulb's fluorescent coating, which re-radiates the energy at lower frequencies (longer wavelengths) to emit visible light. The blend of phosphors controls the color of the light, and along with the bulb's glass prevents the harmful UV light from escaping. Gas (actually, as), the GNU assembler, is the default GCC back-end. ... This article is about plasma in the sense of an ionized gas. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized cadmium selenide (CdSe) quantum dots. ... Hot metal work from a blacksmith In chemistry, a metal (Greek: Metallon) is an element that readily forms ions (cations) and has metallic bonds, and metals are sometimes described as a lattice of positive ions (cations) in a cloud of electrons. ... A rare earth is an oxide of a rare earth element. ... A phosphor is a substance that can exhibit the phenomenon of fluorescence (glowing during absorption of radiation of another kind) or phosphorescence (sustained glowing without further stimulus). ... In chemistry, salt is a general term used for ionic compounds composed of positively charged cations and negatively charged anions, so that the product is neutral and without a net charge. ... Diagram of a copper cathode The electrode of an electrochemical cell at which reduction occurs is referred to as the cathode (from the Greek word κάθοδος = going down). In an electrolytic cell the cathode is negatively charged and in a galvanic cell the cathode is positively charged. ... Ultraviolet (UV) radiation is electromagnetic radiation of a wavelength shorter than that of the visible region, but longer than that of soft X-rays. ... The wavelength is the distance between repeating units of a wave pattern. ... A nanometre (American spelling: nanometer, symbol: nm) is 1. ... Absorption has a number of meanings: In physics absorption is a process in which particles of some sort encounter another material and are taken up by or even disappear in it. ... Electromagnetic radiation or EM radiation is a combination (cross product) of oscillating electric and magnetic fields perpendicular to each other, moving through space as a wave, effectively transporting energy and momentum. ... The optical spectrum (light or visible spectrum) is the portion of the electromagnetic spectrum that is visible to the human eye. ... Color is an important part of the visual arts. ... The materials definition of a glass is a uniform amorphous solid material, usually produced when a suitably viscous molten material cools very rapidly, thereby not giving enough time for a regular crystal lattice to form. ...

Fluorescent lamps are negative resistance devices: as more current flows through them and more gas is ionized, the resistance of the fluorescent lamp drops and this would allow even more current to flow through them! Connected directly to a constant-voltage mains power line, a fluorescent lamp would rapidly self-destruct due to the unlimited current flow. Because of this, fluorescent lamps are always used with some sort of auxiliary electronics that regulates the current flow in the tube. This auxiliary device is commonly called a ballast. In electrical circuits, static resistance is the ratio of the voltage across a circuit element to the current through it. ... In the physical sciences, potential difference is the difference in potential between two points in a conservative vector field. ... Ballast may mean: track ballast: gravel or cinders forming the railroad or railway track-bed on which sleepers (ties) and track is laid, for proper drainage ships ballast: water, sand, rocks, or bricks used to weight a ship down when it has very little cargo (though water may contain...

While the ballast could be (and occasionally is) as simple as a resistor, substantial power is wasted in a resistive ballast so ballasts usually use a reactance (inductor or capacitor) instead. For operation from mains voltage, the use of simple inductor (a so-called "magnetic ballast") is common. In countries that use 120 V AC mains, the mains voltage is insufficient to light large fluorescent lamps so the ballast for these larger fluorescent lamps is often a step-up autotransformer with substantial leakage inductance (so as to limit the current flow). Either form of inductive ballast may also include a capacitor for power factor correction. More sophisticated ballasts may employ transistors or other semiconductor components to convert mains voltage into high-frequency AC while also regulating the current flow in the lamp. These are referred to as "electronic ballasts". A resistor is a two-terminal electrical component that creates an electrical potential difference across its terminals that is proportional to the current passing through it. ... This article is about electronics. ... An inductor is a passive electrical device that stores energy in a magnetic field, typically by combining the effects of many loops of electric current. ... Various types of capacitors A capacitor (occasionally referred to using the older term condenser) is a device that stores energy in the electric field created between a pair of conductors on which equal but opposite electric charges have been placed. ... In physics, magnetism is a phenomenon by which materials exert an attractive or repulsive force on other materials. ... The volt is the SI derived unit for electric potential and voltage (derived from the ampere and watt). ... An alternating current (AC) is an electrical current where the magnitude and direction of the current varies cyclically, as opposed to direct current, where the direction of the current stays constant. ... Transformers - Typical electrical configurations. ... Leakage inductance is that property of an electrical transformer that causes a winding to appear to have some pure inductance in series with the mutually-coupled transformer windings. ... Various types of capacitors A capacitor (occasionally referred to using the older term condenser) is a device that stores energy in the electric field created between a pair of conductors on which equal but opposite electric charges have been placed. ... The power factor of an AC electric power system is defined as the ratio of the real power to the apparent power. ... Through hole transistors (tape measure marked in centimeters) The transistor is a solid state semiconductor device which can be used for amplification, switching, voltage stabilization, signal modulation and many other functions. ... A semiconductor is a material which has an electrical conductance which is between that of an insulator and a conductor. ... Sine waves of various frequencies; the lower waves have higher frequencies than those above. ... An alternating current (AC) is an electrical current where the magnitude and direction of the current varies cyclically, as opposed to direct current, where the direction of the current stays constant. ... Look up Electronic in Wiktionary, the free dictionary Electronic can refer to many things: Objects related to electronics The band Electronic. ...

The mercury atoms in the fluorescent tube must be ionized before the arc can "strike" within the tube. For small lamps, it does not take much voltage to strike the arc and starting the lamp presents no problem, but larger tubes require a substantial voltage (in the range of a thousand volts). In some cases, that is exactly how it is done: "instant start" fluorescent tubes simply use a high enough voltage to break down the gas and mercury column and thereby start arc conduction. These tubes can be identified by the facts that

In other cases, a separate starting aid must be provided. Old fluorescent designs used a combination filament/cathode at each end of the lamp combined with a mechanical or automatic switch that would initially connect the filaments in series and thereby "preheat" the filaments prior to striking the arc. Because of thermionic emission, the filaments would readily emit electrons into the gas column creating a glow discharge near the filaments. Then, when the starting switch opened up, the inductive ballast would create a voltage surge which would (usually) strike the arc. If so, the impinging arc then kept the filament/cathode warm. If not, the starting sequence was repeated. If the starting aid was automatic, this often led to the situation where an old fluorescent lamp would flash time and time again as the starter repeatedly tried to start the worn-out lamp. More advanced starters would "trip out" in this situation and not attempt another start until manually reset. Sign warning of possible electric shock hazard An electric shock may occur upon contact with electricity. ... A filament is a fine, thinly spun thread, fiber, or wire. ... Diagram of a copper cathode The electrode of an electrochemical cell at which reduction occurs is referred to as the cathode (from the Greek word κάθοδος = going down). In an electrolytic cell the cathode is negatively charged and in a galvanic cell the cathode is positively charged. ... Thermionic emission (archaicly known as the Edison effect) is the flow of electrons from a metal or metal oxide surface, caused by thermal vibrational energy overcoming the electrostatic forces holding electrons to the surface. ...

Newer lamp and ballast designs (known as "rapid start" lamps) provide true filament windings within the ballast; these rapidly and continuously warm the filaments/cathodes using low-voltage AC. Unfortunately, there is no inductive voltage surge produced so the lamps must usually be mounted near a grounded (earthed) reflector to allow the glow discharge to propagate through the tube and initiate the arc discharge. Electronic ballasts often revert to a style in-between the preheat and rapid-start styles: a capacitor or other electronic circuit may join the two filaments, providing a conduction path that preheats the filaments but which is subsequently shorted out by the arc discharge. Generally this capacitor also forms, together with the inductor that provides current limiting in normal operation, a resonant circuit increasing the voltage across the lamp so that it can easily start. Some electronic ballasts use programmed start, the output AC frequency is started above the resonance frequency of the output circuit of the ballast, and after the filaments are heated, the frequency is rapidly decreased. If the frequency approaches the resonant frequency of the ballast, the output voltage will increase so much that the lamp will ignite. If the lamp does not ignite an electronic circuit stops the operation of the ballast. In physics, resonance is the tendency of a system to absorb more oscillatory energy when the frequency of the oscillations matches the systems natural frequency of vibration (its resonant frequency) than it does at other frequencies. ... Sine waves of various frequencies; the lower waves have higher frequencies than those above. ... This article is about resonance in physics. ...

Usage

Fluorescent light bulbs come in many shapes and sizes. An increasingly popular one is the compact fluorescent light bulb (CF). Many compact fluorescent lamps integrate the auxiliary electronics into the base of the lamp allowing them to then screw into a regular light bulb socket. Compact fluorescent light bulb A compact fluorescent light bulb (CFL bulb) is a type of fluorescent lamp which screws into a regular light bulb socket, or plugs into a small lighting fixture. ...

Unfortunately, many people find the color spectrum produced by some fluorescent lighting to be harsh and displeasing. It is common for a healthy person to appear with a sickly bluish skin tone under fluorescent lighting, and many pigments have a slightly different color when viewed under fluorescent light versus incandescent. This is mainly the case with fluorescent lamps containing the older halophosphate type phosphors (chemical formula Ca₅(P O₄)₃(F,Cl):Sb³⁺,Mn²⁺), usually labeled as "cool white". The bad color reproduction is due to the fact that this phosphor mainly emits yellow and blue light, and relatively little green and red. To the eye, this mixture looks white, but light reflected from surfaces has a distorted color. More expensive fluorescent lamps use a triphosphor mixture, based on europium and terbium ions, that have emission bands that are more evenly distributed over the spectrum of visible light and hence lead to more natural color reproduction. Model of the layers of human skin In zootomy and dermatology, skin is an organ of the integumentary system; which is composed of a layer of tissues that protect underlying muscles and organs. ... In biology, pigment is any material resulting in color in plant or animal cells which is the result of selective absorption. ... A phosphor is a substance that can exhibit the phenomenon of fluorescence (glowing during absorption of radiation of another kind) or phosphorescence (sustained glowing without further stimulus). ... General Name, Symbol, Number calcium, Ca, 20 Series alkaline earth metal Group, Period, Block 2 (IIA), 4, s Density, Hardness 1550 kg/m3, 1. ... This article is about the chemical element. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... General Name, Symbol, Number Fluorine, F, 9 Series Halogens Group, Period, Block 17 (VIIA), 2, p Density, Hardness 1. ... General Name, Symbol, Number chlorine, Cl, 17 Series halogens Group, Period, Block 17 (VIIA), 3, p Density, Hardness 3. ... General Name, Symbol, Number antimony, Sb, 51 Series metalloids Group, Period, Block 15 (VA), 5, p Density, Hardness 6697 kg/m3, 3 Appearance silvery lustrous grey Atomic properties Atomic weight 121. ... General Name, Symbol, Number manganese, Mn, 25 Chemical series transition metals Group, Period, Block 7 , 4, d Density, Hardness 7470 kg/m3, 6. ... General Name, Symbol, Number Europium, Eu, 63 Chemical series Lanthanides Group, Period, Block _, 6, f Density, Hardness 5244 kg/m3, no data Appearance silvery white Atomic properties Atomic weight 151. ... General Name, Symbol, Number Terbium, Tb, 65 Chemical series Lanthanides Period, Block 6, f Density, Hardness 8219 kg/m3, no data Appearance silvery white Atomic properties Atomic weight 158. ...

In the US, Residential use of fluorescent lighting remains low (generally limited to kitchens, basements, hallways and other areas), but schools and businesses find the cost savings of fluorescents to be significant and only rarely use incandescent lights. Typical lighting arrangements may include fluorescent tubes sending different tints of white, in order to provide good color reproduction. In other countries, Residential use of fluorescent lighting varies depending on the price of energy and the environmental concerns of the local population as well as the acceptability of the light output. A residential area is a type of land use where the predominant use is residential. ... A kitchen is a room used for food preparation. ... A basement is an architectural contruction that is completely or almost below ground in a building. ... Hall is a term often used to refer to several different types of room in a house or a building. ... Japanese secondary school students in uniform A school is most commonly a place designated for learning. ... Business refers to at least three closely related commercial topics. ... A residential area is a type of land use where the predominant use is residential. ...

Because they contain mercury, a toxic material, in quantities of a few milligrams per unit, in many areas throughout the world government regulations require that fluorescent bulbs must be properly disposed of. This generally applies only to large commercial buildings which produce many waste bulbs, though restrictions vary widely. For a list of biologically injurious substances, including toxins and other materials, as well as their effects, see poison. ... The milligram (symbol mg) is an SI unit of mass. ...

Tube designations

Note: the information in this section may or may not be applicable outside of North America. World map showing location of North America A satellite composite image of North America North America is the third largest continent in area and fourth in population after Asia and Africa in area and population and Europe in population. ...

Bulbs are typically identified by a code such as F##T##, where F is for fluorescent, the first number indicates the power in watts (or strangely, length in inches in very long bulbs), the T indicates that the shape of the lamp is tubular, and the last number is diameter in eighths of an inch. Typical diameters are T12 (1½" or 38mm) for residential bulbs with old magnetic ballasts, T8 (1" or 25mm) for commercial energy-saving bulbs with electronic ballasts, and T5 (⁵/8" or 16mm) for very small bulbs which may even operate from a battery-powered device. Identification can mean The act of identifying. ... In communications, a code is a rule for converting a piece of information (for example, a letter, word, or phrase) into another form or representation, not necessarily of the same sort. ... Mid-19th century tool for converting between different standards of the inch An inch is an Imperial unit of length. ... TUBE (チューブ; chūbu) is a Japanese popular music group. ... In geometry, a diameter (Greek words diairo = divide and metro = measure) of a circle is any straight line segment that passes through the center and whose endpoints are on the circular boundary, or, in more modern usage, the length of such a line segment. ... A millimetre (American spelling: millimeter), symbol mm is an SI unit of length that is equal to one thousandth of a metre. ... Magnetic lines of force of a bar magnet shown by iron filings on paper A magnet is an object that has a magnetic field. ... Transformers - Typical electrical configurations. ... Look up Electronic in Wiktionary, the free dictionary Electronic can refer to many things: Objects related to electronics The band Electronic. ... Four double-A batteries In science and technology, a battery is a device that stores energy and makes it available in an electrical form. ... Transmission lines in Lund, Sweden Electric power, often known as power or electricity, involves the production and delivery of electrical energy in sufficient quantities to operate domestic appliances, office equipment, industrial machinery and provide sufficient energy for both domestic and commercial lighting, heating, cooking and industrial processes. ... A Device can be taken to mean: an electrical device designed to carry power, but not use it. ...

High-output bulbs are brighter and draw more electrical current, have different ends on the pins so they cannot be used in the wrong fixture or with the wrong bulb, and are labeled F##T12HO, or F##T12VHO for very high output. Information processing In information processing, output is the process of transmitting information (verb usage). ... In electricity, current is the rate of flow of charges, usually through a metal wire or some other electrical conductor. ... This article is in need of attention. ...

U-shaped tubes are FB##T##, with the B meaning "bent". Most commonly, these have the same designations as linear tubes. Circular bulbs are FC##T#, with the diameter of the circle (not circumference or watts) being the first number, and the second number usually being 9 (29mm) for standard fixtures. The circumference is the distance around a closed curve. ...

Color is usually indicated by WW for whar white, EW for enhanced (neutral) white, CW for cool white (the most common), and DW for the bluish daylight white. BL is often used for blacklight (commonly used in bug zappers), and BLB for the common blacklight-blue bulbs which are dark purple. Other non-standard designations apply for plant lights or grow lights. The term Daylight can have several meanings: Sunlight The title of an album - Daylight (album) The title of a movie - Daylight (movie) The Southern Pacific railroad operated several named passenger trains named [adjective] Daylight (such as the Afternoon Daylight) in California. ... Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... Function A bug zapper uses a strong electrical current to kill insects that are attracted to it due to a light source in the center of the device. ...

Odd lengths are usually added after the color. One example is an F25T12/CW/33, meaning 25 watts, 1.5" diameter, cool white, 33" or 84cm long. Without the 33, it would be assumed that an F25T12 is the more-common 30" long.

Blacklights, sun lamps, and germicidal lamps

Blacklights are a subset of fluorescent lamps that are used to provide long-wave ultraviolet light (at about 360nm wavelength). They are built in the same fashion as conventional fluorescent lamps but the glass tube is coated with a phosphor that converts the short-wave UV within the tube to long-wave UV rather than to visible light. Note: Ultraviolet is also the name of a 1998 UK television miniseries about vampires. ... Ultraviolet (UV) radiation is electromagnetic radiation of a wavelength shorter than that of the visible region, but longer than that of soft X-rays. ...

Most blacklights (so-called "BLB" or "BlackLight-Blue" lamps) are also made from more-expensive deep blue glass rather than clear glass. The deep blue glass filters out most of the visible colors of light directly emitted by the mercury vapor discharge, producing proportionally more UV light and less visible light so your blacklight posters look better. The blacklight lamps used in bug zappers does not require this refinement so it is usually omitted in the interest of low cost.

Sun lamps contain a different phosphor that emits more strongly in medium-wave UV, provoking a tanning response in human skin. A model of Scentual Sun demonstrates the differences between clear skin and a sun tan. ... Binomial name Homo sapiens Linnaeus, 1758 Subspecies Homo sapiens idaltu (extinct) Homo sapiens sapiens Human beings define themselves in biological, social, and spiritual terms. ... Model of the layers of human skin In zootomy and dermatology, skin is an organ of the integumentary system; which is composed of a layer of tissues that protect underlying muscles and organs. ...

Finally, germicidal lamps contain no phosphor at all and their tubes are made of fused quartz that is transparent to the short-wave UV directly emitted by the mercury discharge. The UV emitted by these tubes will kill germs, ionize oxygen to ozone, and cause eye and skin damage. Besides their uses to kill germs and create ozone, they are sometimes used by geologists to identify certain species of minerals by the color of their fluorescence. When used in this fashion, they are fitted with filters in the same way as Blacklight-Blue lamps are; the filter passes the short-wave UV and blocks the visible light produced by the mercury discharge. Fused quartz is a man-made material manufactured principally from sands. ... General Name, Symbol, Number oxygen, O, 8 Chemical series nonmetals Group, Period, Block 16, 2, p Appearance colorless Atomic mass 15. ... Ozone (O3) is an allotrope of oxygen, the molecule consisting of three oxygen atoms instead of the more stable diatomic O2. ... This article is about disease-causing organisms. ... A geologist is a contributor to the science of geology. ... Minerals are natural compounds formed through geological processes. ... Fluorescence induced by exposure to ultraviolet light in vials containing various sized cadmium selenide (CdSe) quantum dots. ...

Induction lamps

It is possible to build a fluorescent lamp without any internal electrodes. Instead, a current is induced into the gas column using electromagnetic induction. Because the electrodes are usually the life-limiting element of fluorescent lamps, such electrode-less lamps can have a very long service life (although they also have a higher purchase price). For more details, see induction lighting. Electromagnetic induction is the production of an electrical potential difference (or voltage) across a conductor situated in a changing magnetic flux. ...

Fluorescent fun

If you live in a dry cold climate with lots of static electricity, try this: Put on your best static gathering socks and take hold of a short fluorescent tube. Then shuffle about on the carpet to gather a robust static charge. Now discharge by gently touching the lamp electrodes to anything electrically grounded. Instead of the usual little spark the entire tube will flash as the electrons course (painlessly) out of your body. This also applies with Van de Graaff generators; simply touch the light to the sphere or touch the sphere while holding the light. Warning: This may produce a rather "jolty" shock. Static electricity or electrostatics is a field of science and a class of phenomena involving the imbalanced charge present on an object, typically referring to charge with voltage of sufficient magnitude to produce visible attraction, repulsion, and sparks. ... The SOCKS Protocol is an Internet protocol that allows client-server applications to transparently use the services of a network firewall. ... An electrode is a conductor used to make contact with a nonmetallic part of a circuit (e. ... Properties The electron (also called negatron, commonly represented as e−) is a subatomic particle. ... Van de Graaff generator A Van de Graaff generator is a machine which uses a moving belt to accumulate very high charges on a hollow metal globe. ...

Alternatively, if you happen to have a Tesla coil handy, you can fully illuminate the fluorescent lamp at quite a distance from the Tesla coil simply by holding the detached lamp in your hand and possibly touching one of its terminals. Do not touch the lamp to the coil, as this may result in injury and/or burning out the lamp (a hobbyist Tesla coil may operate at several kilowatts). A Tesla coil is a category of disruptive discharge coils, named after their inventor, Nikola Tesla. ...

If you live near high voltage power lines you might try standing underneath them at night while holding a fluorescent tube. The strong electric field created by power lines will cause a very small (harmless) current flow through the tube and it should give off at least a feeble glow.[1] Obviously you should never do this during stormy weather and no attempt should ever be made to get closer to the lines using, for instance, a ladder. Electric power transmission is the second process in the delivery of electricity to consumers. ... Multiple cloud-to-ground and cloud-to-cloud lightning strokes are observed during a night-time thunderstorm. ...

External links

Categories: Lighting | Electric power | Plasma physics Prism splitting light Light is electromagnetic radiation with a wavelength that is visible to the eye, or in a more general sense, any electromagnetic radiation in the range from infrared to ultraviolet. ... Architect lamps Lighting refers to the devices or techniques used for illumination, usually referring to artificial light sources such as lamps or flashlights. ... Bioluminescence is the production and emission of visible light by a living organism as the result of a chemical reaction during which chemical energy is converted to light energy. ... Genera Curtos Cyphonocerus Drilaster Ellychnia Hotaria Lampyris Lucidina Luciola - (Japanese fireflies) Photinus - (common eastern firefly) Photuris Pristolycus Pyractomena Pyrocoelia Stenocladius Fireflies (family Lampyridae), also known as lightning bugs, are nocturnal, luminous beetles. ... Foxfire is the term for an eerie glow in the forest generally attributed to bioluminescent fungus (genus Armillaria) which grows on decaying wood. ... See also lists of astronomical objects for a list of the various lists of astronomical objects in Wikipedia. ... Multiple cloud-to-ground and cloud-to-cloud lightning strokes are observed during a night-time thunderstorm. ... Combustion or burning is an exothermic reaction between a substance (the fuel) and a gas (the oxidizer) to release heat. ... Carbide lamps (acetylene lamps) are simple lamps that produce and burn acetylene by reacting calcium carbide with water. ... A lit candle. ... The Davy lamp is a safety lamp devised in 1815 by Humphry Davy. ... Fire is a form of combustion. ... Gas lighting is the process of burning piped natural gas or coal gas for illumination. ... The Kerosene lamp, widely known in Britain as the Paraffin lamp, is any type of lighting device which uses kerosene (paraffin) as a fuel. ... Limelight is a type of stage lighting once used in theatres and music halls. ... An oil lamp is a device used for lighting or for preserving a flame that is fueled by animal, vegetable or mineral oil. ... A Rushlight is a type of candle formed using the dried pith of the rush plant as its wick. ... In nuclear physics, a nuclear reaction is a process in which two nuclei or nuclear particles collide, to produce products different to the initial products. ... Lightsticks Chemoluminescence (sometimes chemiluminescence) is the emission of light (luminescence) as the result of a chemical reaction. ... A betalight is an artificial light source powered by the radioactive decay of tritium (3H) gas. ... Lightsticks Chemoluminescence (sometimes chemiluminescence) is the emission of light (luminescence) as the result of a chemical reaction. ... Three types of lightsticks in five colours A lightstick, also called a glowstick, is a transparent plastic tube which contains chemical fluids held apart in two compartments. ... Electricity is a property of certain subatomic particles (e. ... The 300,000-watt Plasma Arc Lamp in the Infrared Processing Center (IPC) at Oak Ridge National Laboratory An arc lamp is a device that produces light by the sparking (or arcing, from voltaic arc or electric arc) of a high current between two carbon rod electrodes. ... The incandescent light bulb (archaically known as the electric lamp) uses a glowing wire filament heated to white-hot by electrical resistance, to generate light (a process known as thermal radiation or incandescence). ... High-intensity discharge (HID) lamps include the groups of lamps commonly known as mercury vapor, metal halide, and high-pressure sodium. ... Hydrargyrum Medium-Arc Iodide, frequently called just HMI is a mercury-halide discharge short arc lamp with a color temperature of approximately 5600K. The name is derived from Hydrargyrum, an archaic term for mercury while Iodide indicates that iodine is the halogen used to form the active compound. ... A Mercury Vapor Lamp is a gas discharge lamp which uses mercury in an excited state to produce light. ... Metal halide lamps are similar to Mercury vapor lamps, but instead of just mercury, they also contain all metals in the halide group of the periodic table (Hence the name). ... A sodium vapor lamp is a gas discharge lamp which uses sodium in an excited state to produce light. ... Xenon arc lamps are a source of artificial light. ... Electroluminescence is an optical phenomenon and electrical phenomenon where a material such as a natural blue diamond emits light when an electric current is passed through it. ... Induction lighting or inductive lighting is a means of fluorescent lighting, which uses RF induction of radio waves to produce radiofluorescence. ... Various light-emitting diodes (5 mm reds, 3 mm greens and yellows) A light-emitting diode (LED) is a semiconductor device that emits incoherent monochromatic light when electrically biased in the forward direction. ... A neon lamp is a gas discharge lamp containing neon gas at low pressure. ... Induction lighting or inductive lighting is a means of fluorescent lighting, which uses RF induction of radio waves to produce radiofluorescence. ... Xenon flash lamp being fired. ... A Yablochkov candle (sometimes electric candle) is a type of electric carbon arc lamp, invented in 1876 by Pavel Yablochkov. ...

Contents

History GA_googleFillSlot("encyclopedia_square");