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Mercury Arc Valve
A mercury-arc valve or mercury-vapor rectifier or (UK) mercury-arc rectifier is a type of electrical rectifier used for converting high-voltage or high- current alternating current (AC) into direct current (DC). It is a type of cold cathode gas-filled tube, but is unusual in that the cathode, instead of being solid, is made from a pool of liquid mercury and is therefore self-restoring. As a result mercury-arc valves, when used as intended, are far more robust and durable and can carry much higher currents than most other types of gas discharge tube. Some examples have been in continuous service, rectifying 50-ampere currents, for decades. Invented in 1902 by Peter Cooper Hewitt, mercury-arc rectifiers were used to provide power for industrial motors, electric railways, streetcars, and electric locomotives, as well as for radio transmitters and for high-voltage direct current (HVDC) power transmission. They were the primary method of high power rectification before the advent of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Diode
A diode is a two-Terminal (electronics), terminal electronic component that conducts electric current primarily in One-way traffic, one direction (asymmetric electrical conductance, conductance). It has low (ideally zero) Electrical resistance and conductance, resistance in one direction and high (ideally infinite) resistance in the other. A semiconductor diode, the most commonly used type today, is a Crystallinity, crystalline piece of semiconductor material with a p–n junction connected to two electrical terminals. It has an Exponential function, exponential current–voltage characteristic. Semiconductor diodes were the first Semiconductor device, semiconductor electronic devices. The discovery of asymmetric electrical conduction across the contact between a Crystal, crystalline mineral and a metal was made by German physicist Ferdinand Braun in 1874. Today, most diodes are made of silicon, but other semiconducting materials such as gallium arsenide and germanium are also ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Arc
An electric arc (or arc discharge) is an electrical breakdown of a gas that produces a prolonged electrical discharge. The electric current, current through a normally Electrical conductance, nonconductive medium such as air produces a plasma (physics), plasma, which may produce visible light. An arc discharge is initiated either by thermionic emission or by field emission. After initiation, the arc relies on thermionic emission of electrons from the electrodes supporting the arc. An arc discharge is characterized by a lower voltage than a glow discharge. An archaic term is voltaic arc, as used in the phrase "voltaic arc lamp". Techniques for arc suppression can be used to reduce the duration or likelihood of arc formation. In the late 19th century, Arc lamp, electric arc lighting was in wide use for Street light#Arc lamps, public lighting. Some low-pressure electric arcs are used in many applications. For example, fluorescent lamp, fluorescent tubes, mercury, sodium, and met ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mercury Arc Rectifier
A mercury-arc valve or mercury-vapor rectifier or (UK) mercury-arc rectifier is a type of electrical rectifier used for converting high-voltage or high-Electric current, current alternating current (AC) into direct current (DC). It is a type of cold cathode gas-filled tube, but is unusual in that the cathode, instead of being solid, is made from a pool of liquid mercury (element), mercury and is therefore self-restoring. As a result mercury-arc valves, when used as intended, are far more robust and durable and can carry much higher currents than most other types of gas discharge tube. Some examples have been in continuous service, rectifying 50-ampere currents, for decades. Invented in 1902 by Peter Cooper Hewitt, mercury-arc rectifiers were used to provide power for industrial motors, railway electrification system, electric railways, Tram, streetcars, and electric locomotives, as well as for radio transmitters and for high-voltage direct current (HVDC) power transmission. They w ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Semiconductor Rectifier
A semiconductor is a material with electrical conductivity between that of a conductor and an insulator. Its conductivity can be modified by adding impurities (" doping") to its crystal structure. When two regions with different doping levels are present in the same crystal, they form a semiconductor junction. The behavior of charge carriers, which include electrons, ions, and electron holes, at these junctions is the basis of diodes, transistors, and most modern electronics. Some examples of semiconductors are silicon, germanium, gallium arsenide, and elements near the so-called " metalloid staircase" on the periodic table. After silicon, gallium arsenide is the second-most common semiconductor and is used in laser diodes, solar cells, microwave-frequency integrated circuits, and others. Silicon is a critical element for fabricating most electronic circuits. Semiconductor devices can display a range of different useful properties, such as passing current more easily in o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trolleybus
A trolleybus (also known as trolley bus, trolley coach, trackless trolley, trackless tramin the 1910s and 1920sJoyce, J.; King, J. S.; and Newman, A. G. (1986). ''British Trolleybus Systems'', pp. 9, 12. London: Ian Allan Publishing. .or trolleyDunbar, Charles S. (1967). ''Buses, Trolleys & Trams''. Paul Hamlyn Ltd. (UK). Republished 2004 with or 9780753709702.) is an electric bus that draws power from dual overhead wires (generally suspended from roadside posts) using spring-loaded or pneumatically raised trolley poles. Overhead line#Parallel overhead lines, Two wires, and two trolley poles, are required to complete the electrical circuit. This differs from a tram or streetcar, which normally uses the track as the return path, needing only one wire and one pole (or pantograph (transport), pantograph). They are also distinct from other kinds of Battery electric bus, electric buses, which usually rely on Automotive battery, batteries. Power is most commonly supplied as 600-volt ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International Textbook Company
The International Textbook Company (I.T.C.) was founded in 1895 by publisher Thomas J. Foster in Scranton, Pennsylvania. I.T.C. published instructional papers, booklets, and textbooks for the International Correspondence Schools, a subsidiary department. The textbook company and the school were dependent on each other since their founding. The International Correspondence School started in 1891 as a question-answer column in the pages of the mining journal ''Colliery Engineer and Metal Miner'', also published by Foster. This column was a response to the in-depth tests required of miners and inspectors by the Pennsylvania Mine Safety Act of 1885. The I.T.C. merged the Colliery Engineer School of Mines, School of Mines, Correspondence Schools, and the International Correspondence School as the International Correspondence Schools of Scranton, Pennsylvania, under the new International Textbook Company. Several Scranton correspondence schools had textbooks printed or published by ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arc Lamp
An arc lamp or arc light is a lamp that produces light by an electric arc (also called a voltaic arc). The carbon arc light, which consists of an arc between carbon electrodes in air, invented by Humphry Davy in the first decade of the 1800s, was the first practical electric light. It was widely used starting in the 1870s for street and large building lighting until it was superseded by the incandescent light in the early 20th century. It continued in use in more specialized applications where a high intensity point light source was needed, such as searchlights and movie projectors until after World War II. The carbon arc lamp is now obsolete for most of these purposes, but it is still used as a source of high intensity ultraviolet light. The term is now used for gas discharge lamps, which produce light by an arc between metal electrodes through a gas in a glass bulb. The common fluorescent lamp is a low-pressure mercury arc lamp. The xenon arc lamp, which produces a high ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Rotary Converter
A rotary converter is a type of electrical machine which acts as a mechanical rectifier, Power inverter, inverter or frequency converter. Rotary converters were used to convert alternating current (AC) to direct current (DC), or DC to AC power, before the advent of chemical or Solid state (electronics), solid state power rectification and inverting. They were commonly used to provide DC power for commercial, industrial and railway electrification from an AC power source. Principles of operation The rotary converter can be thought of as a motor–generator, where the two machines share a single rotating armature (electrical engineering), armature and set of field coils. The basic construction of the rotary converter consists of a DC generator (dynamo) with a set of slip rings tapped into its rotor windings at evenly spaced intervals. When a dynamo is spun the electric currents in its rotor windings alternate as it rotates in the magnetic field of the stationary field windin ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Philosophical Magazine
The ''Philosophical Magazine'' is one of the oldest scientific journals published in English. It was established by Alexander Tilloch in 1798;John Burnett"Tilloch, Alexander (1759–1825)" Dictionary of National Biography#Oxford Dictionary of National Biography, Oxford Dictionary of National Biography, Oxford University Press, Sept 2004; online edn, May 2006, accessed 17 Feb 2010 in 1822 Richard Taylor (editor), Richard Taylor became joint editor and it has been published continuously by Taylor & Francis ever since. Early history The name of the journal dates from a period when "natural philosophy" embraced all aspects of science. The very first paper published in the journal carried the title "Account of Mr Cartwright's Patent Steam Engine". Other articles in the first volume include "Methods of discovering whether Wine has been adulterated with any Metals prejudicial to Health" and "Description of the Apparatus used by Lavoisier to produce Water from its component Parts, Oxyg ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Comptes Rendus De L'Académie Des Sciences
(, ''Proceedings of the Academy of Sciences''), or simply ''Comptes rendus'', is a French scientific journal published since 1835. It is the proceedings of the French Academy of Sciences. It is currently split into seven sections, published on behalf of the Academy until 2020 by Elsevier: ''Mathématique, Mécanique, Physique, Géoscience, Palévol, Chimie, ''and'' Biologies.'' As of 2020, the ''Comptes Rendus'' journals are published by the Academy with a diamond open access model. Naming history The journal has had several name changes and splits over the years. 1835–1965 ''Comptes rendus'' was initially established in 1835 as ''Comptes rendus hebdomadaires des séances de l'Académie des Sciences''. It began as an alternative publication pathway for more prompt publication than the ''Mémoires de l'Académie des Sciences,'' which had been published since 1666. The ''Mémoires,'' which continued to be published alongside the ''Comptes rendus'' throughout the ninetee ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Jules Jamin
Jules Célestin Jamin (31 May 1818 – 12 February 1886) was a French physicist. He was professor of physics at École polytechnique from 1852 to 1881 and received the Rumford Medal in 1858 for his work on light. He improved David Brewster's inclined interference plates with the development of the Jamin interferometer. Biography Early life Jules Jamin, son of Anthony Peter Jamin, was born in 1818 in Termes, Ardennes, France. He began his education at a small school in Vouziers, a small village located in northeast France. After some time there, he was sent to the college at Reims by his father, Antoine-Pierre. In his first year at the college at Reims Jules won nine awards. In 1838 he won the science competition award with honors, and in October of the same year he was accepted on first selection to enter École normale supérieure where he obtained a degree in physical sciences, mathematics and natural sciences. In 1841, he graduated first in the competition of comprehensi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
