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Skiatron
The skiatron is a type of cathode ray tube (CRT) that replaces the conventional phosphor with some type of scotophor, typically potassium chloride. When hit by the electron beam from the back of the CRT, this normally white material turns a magenta color, producing a dark spot or line on the display. The pattern remains on the display until erased by heating the potassium chloride layer. Skiatrons were used as an early form of projection television display, particularly in radar stations during World War II. These tubes are also sometimes known as dark trace CRTs or dark trace tubes. Description During World War II, radar displays using potassium chloride evaporated on a mica plate as target material were actively developed in England, Germany, the United States, and the Soviet Union. Being naturally cathodochromic, potassium chloride did not require any special processing or treatment to become a CRT target material. When hit by the electron beam from the back of the CRT, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Direct-view Bistable Storage Tube
Direct-view bistable storage tube (DVBST) was an acronym used by Tektronix to describe their line of storage tubes. These were cathode ray tubes (CRT) that stored information written to them using an analog technique inherent in the CRT and based upon the secondary emission of electrons from the phosphor screen itself. The resulting image was visible in the continuously glowing patterns on the face of the CRT. DVBST technology was anticipated by Andrew Haeff of the US Naval Research Laboratory, and by Williams and Kilburn in the late 1940s. Tek's (Tektronix) Robert H. Anderson refined Haeff's concepts in the late 1950s to produce a reliable and simple DVST. Principle The DVBST implements two electron guns: a "flood gun" and a "writing gun". The writing gun scans across a wire grid, charging the grid to create the negative image. The flood gun then floods the grid. Previously charged areas repel the incoming electrons so that electrons only pass through the grid to the phosphor ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scotophor
A scotophor is a material showing reversible darkening and bleaching when subjected to certain types of radiation. The name means ''dark bearer'', in contrast to phosphor, which means ''light bearer''. Scotophors show tenebrescence (reversible photochromism) and darken when subjected to an intense radiation such as sunlight. Minerals showing such behavior include hackmanite sodalite, spodumene and tugtupite. Some pure alkali halides also show such behavior. Scotophors can be sensitive to light, particle radiation (e.g. electron beam – see cathodochromism), X-rays, or other stimuli. The induced absorption bands in the material, caused by F-centers created by electron bombardment, can be returned to their non-absorbing state, usually by light and/or heating. Scotophors sensitive to electron beam radiation can be used instead of phosphors in cathode ray tubes, for creating a light absorbing instead of light emitting image. Such displays are viewable in bright light and the image is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Potassium Chloride
Potassium chloride (KCl, or potassium salt) is a metal halide salt composed of potassium and chlorine. It is odorless and has a white or colorless vitreous crystal appearance. The solid dissolves readily in water, and its solutions have a salt-like taste. Potassium chloride can be obtained from ancient dried lake deposits. KCl is used as a fertilizer, in medicine, in scientific applications, domestic water softeners (as a substitute for sodium chloride salt), and in food processing, where it may be known as E number additive E508. It occurs naturally as the mineral sylvite, and in combination with sodium chloride as sylvinite. Uses Fertilizer The majority of the potassium chloride produced is used for making fertilizer, called potash, since the growth of many plants is limited by potassium availability. Potassium chloride sold as fertilizer is known as muriate of potash (MOP). The vast majority of potash fertilizer worldwide is sold as MOP. Medical use Potassium is vital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Phosphor
A phosphor is a substance that exhibits the phenomenon of luminescence; it emits light when exposed to some type of radiant energy. The term is used both for fluorescent or phosphorescent substances which glow on exposure to ultraviolet or visible light, and cathodoluminescent substances which glow when struck by an electron beam (cathode rays) in a cathode-ray tube. When a phosphor is exposed to radiation, the orbital electrons in its molecules are excited to a higher energy level; when they return to their former level they emit the energy as light of a certain color. Phosphors can be classified into two categories: fluorescent substances which emit the energy immediately and stop glowing when the exciting radiation is turned off, and phosphorescent substances which emit the energy after a delay, so they keep glowing after the radiation is turned off, decaying in brightness over a period of milliseconds to days. Fluorescent materials are used in applications in which the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Air Force
The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) and the Royal Naval Air Service (RNAS). Following the Allied victory over the Central Powers in 1918, the RAF emerged as the largest air force in the world at the time. Since its formation, the RAF has taken a significant role in British military history. In particular, it played a large part in the Second World War where it fought its most famous campaign, the Battle of Britain. The RAF's mission is to support the objectives of the British Ministry of Defence (MOD), which are to "provide the capabilities needed to ensure the security and defence of the United Kingdom and overseas territories, including against terrorism; to support the Government's foreign policy objectives particularly in promoting international peace and security". The R ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
History Of Television
The concept of television was the work of many individuals in the late 19th and early 20th centuries. The first practical transmissions of moving images over a radio system used mechanical rotating perforated disks to scan a scene into a time-varying signal that could be reconstructed at a receiver back into an approximation of the original image. Development of television was interrupted by the Second World War. After the end of the war, all-electronic methods of scanning and displaying images became standard. Several different standards for addition of color to transmitted images were developed with different regions using technically incompatible signal standards. Television broadcasting expanded rapidly after World War II, becoming an important mass media, mass medium for advertising, propaganda, and entertainment. Television broadcasts can be distributed over the air by VHF and UHF radio signals from terrestrial transmitting stations, by microwave signals from Earth orbi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Television Technology
Large-screen television technology (colloquially big-screen TV) developed rapidly in the late 1990s and 2000s. Prior to the development of thin-screen technologies, rear-projection television was standard for larger displays, and jumbotron, a non-projection video display technology, was used at stadiums and concerts. Various thin-screen technologies are being developed, but only liquid crystal display (LCD), plasma display (PDP) and Digital Light Processing (DLP) have been publicly released. Recent technologies like organic light-emitting diode (OLED) as well as not-yet-released technologies like surface-conduction electron-emitter display (SED) or field emission display (FED) are in development to replace earlier flat-screen technologies in picture quality. Large-screen technologies have almost completely displaced cathode-ray tubes (CRT) in television sales due to the necessary bulkiness of cathode-ray tubes. The diagonal screen size of a CRT television is limited to abou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moscow Electric Lamp Plant
Moscow Electric Lamp Plant (russian: Московский электроламповый завод) is a company based in Moscow, Russia. The Moscow Electric Lamp Production Association has been a leader in the development and production of vacuum tubes for both civil and military use. It is a major producer of cathode ray tubes (CRTs) for color television receivers, and for many years was one of the largest producers in Russia of photoelectronic multiplier tubes (used in light sensing devices). The Association includes three major production facilities: the Moscow Electrovacuum Instrument Plant, which is co-located with the association; the Khromatron Plant, located elsewhere in Moscow; and the Electrovacuum Instrument Plant in Voronezh. The Moscow Electrovacuum Instrument Plant, with its two associated special design bureaus, specializes in developing and producing a variety of vacuum tube products (photoelectric cell A solar cell, or photovoltaic cell, is an electron ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Movie Projector
A movie projector is an optics, opto-mechanics, mechanical device for displaying Film, motion picture film by projecting it onto a movie screen, screen. Most of the optical and mechanical elements, except for the illumination and sound devices, are present in movie cameras. Modern movie projectors are specially built video projectors. (see also digital cinema) Many projectors are specific to a particular film gauge and not all movie projectors are film projectors since the use of film is required. Predecessors The main precursor to the movie projector was the magic lantern. In its most common setup it had a concave mirror behind a light source to help direct as much light as possible through a painted glass picture slide and a lens, out of the lantern onto a screen. Simple mechanics to have the painted images moving were probably implemented since Christiaan Huygens introduced the apparatus around 1659. Initially candles and oil lamps were used, but other light sources, such ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photographic Display Unit
The Photographic Display Unit, or PDU, was a large-format display system used by the Royal Air Force to present radar images for interpretation by a number of operators and commanders. Made by Kelvin Hughes, it projected a diameter image that could optionally be overlaid with a map and range rings. The PDU was originally designed for the ROTOR system and subsequent AMES Type 80-based Master Radar Stations. A smaller version with a display was used onboard Royal Navy ships, and a larger version projected onto movie screens was used in the SAGE system in the US. Description The PDU was essentially an automated 35mm film processing system. A bright cathode ray tube duplicated the image from one of the radar consoles, while the film was exposed in front of it through an f2 lens. Each complete scanning rotation of the radar took 15 seconds, but as it reached a selected location, normally opposite the direction the radar was designed to observe, the film was pulled out from in front ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Storage Oscilloscope
An oscilloscope (informally a scope) is a type of electronic test instrument that graphically displays varying electrical voltages as a two-dimensional plot of one or more signals as a function of time. The main purposes are to display repetitive or single waveforms on the screen that would otherwise occur too briefly to be perceived by the human eye. The displayed waveform can then be analyzed for properties such as amplitude, frequency, rise time, time interval, distortion, and others. Originally, calculation of these values required manually measuring the waveform against the scales built into the screen of the instrument. Modern digital instruments may calculate and display these properties directly. Oscilloscopes are used in the sciences, medicine, engineering, automotive and the telecommunications industry. General-purpose instruments are used for maintenance of electronic equipment and laboratory work. Special-purpose oscilloscopes may be used to analyze an automotive ign ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Tungsten
Tungsten, or wolfram, is a chemical element with the symbol W and atomic number 74. Tungsten is a rare metal found naturally on Earth almost exclusively as compounds with other elements. It was identified as a new element in 1781 and first isolated as a metal in 1783. Its important ores include scheelite and wolframite, the latter lending the element its alternate name. The free element is remarkable for its robustness, especially the fact that it has the highest melting point of all known elements barring carbon (which sublimes at normal pressure), melting at . It also has the highest boiling point, at . Its density is , comparable with that of uranium and gold, and much higher (about 1.7 times) than that of lead. Polycrystalline tungsten is an intrinsically brittle and hard material (under standard conditions, when uncombined), making it difficult to work. However, pure single-crystalline tungsten is more ductile and can be cut with a hard-steel hacksaw. Tungsten occurs in many ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
