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Igor Grekhov
Igor Vsevolodovich Grekhov (russian: Игорь Всеволодович Грехов, born 10 September 1934 in Smolensk) is a Soviet and Russian physicist and electrical engineer, full member of the Russian Academy of Sciences. He is known as one of the founders of the power semiconductor device industry in the Soviet Union. His contributions to the field of pulsed power devices and converter technique were recognized by the awarding of the Lenin Prize, the two State Prizes and several State orders of Russia. He headed the laboratory at the Ioffe Physical Technical Institute in St. Petersburg over several decades. Professional career Grekhov was born to a family of schoolteachers in Smolensk, but his childhood passed in the city of Simferopol, Crimea.Computer History Museum, oral history Oral History of Igor V. Grekhov(total 44 pages, interviewed by: R. Remacle, May 15, 2012) After finishing secondary school, Grekhov studied electrical engineering at the Bauman Moscow St ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smolensk
Smolensk ( rus, Смоленск, p=smɐˈlʲensk, a=smolensk_ru.ogg) is a city and the administrative center of Smolensk Oblast, Russia, located on the Dnieper River, west-southwest of Moscow. First mentioned in 863, it is one of the oldest cities in Russia. Population: The city has been destroyed several times throughout its long history because it was on the invasion routes of various empires. Smolensk is known for its electronics, textiles, food processing, and diamond faceting industries. Etymology The name of the city is derived from the name of the Smolnya River. Smolnya river flows through Karelian and Murmansk areas of north-western Russia. The origin of the river's name is less clear. One possibility is the old Slavic word () for black soil, which might have colored the waters of the Smolnya. An alternative origin could be the Russian word (), which means resin, tar, or pitch. Pine trees grow in the area, and the city was once a center of resin processing and t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Leningrad
Saint Petersburg ( rus, links=no, Санкт-Петербург, a=Ru-Sankt Peterburg Leningrad Petrograd Piter.ogg, r=Sankt-Peterburg, p=ˈsankt pʲɪtʲɪrˈburk), formerly known as Petrograd (1914–1924) and later Leningrad (1924–1991), is the second-largest city in Russia. It is situated on the Neva River, at the head of the Gulf of Finland on the Baltic Sea, with a population of roughly 5.4 million residents. Saint Petersburg is the fourth-most populous city in Europe after Istanbul, Moscow and London, the most populous city on the Baltic Sea, and the world's northernmost city of more than 1 million residents. As Russia's Imperial capital, and a historically strategic port, it is governed as a federal city. The city was founded by Tsar Peter the Great on 27 May 1703 on the site of a captured Swedish fortress, and was named after apostle Saint Peter. In Russia, Saint Petersburg is historically and culturally associated with ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Step Recovery Diode
In electronics, a step recovery diode (SRD, snap-off diode or charge-storage diode or memory varactor) is a semiconductor junction diode with the ability to generate extremely short pulses. It has a variety of uses in microwave (MHz to GHz range) electronics as pulse generator or parametric amplifier. When diodes switch from forward conduction to reverse cut-off, a reverse current flows briefly as stored charge is removed. It is the abruptness with which this reverse current ceases which characterises the step recovery diode. Historical note The first published paper on the SRD is : the authors start the brief survey stating that "the recovery characteristics of certain types of pn-junction diodes exhibit a discontinuity which may be used to advantage for the generation of harmonics or for the production of millimicrosecond pulses". They also refer that they first observed this phenomenon in February, 1959 Operating the SRD Physical principles The main phenomenon use ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Shockley Diode
The Shockley diode (named after physicist William Shockley) is a four-layer semiconductor diode, which were one of the first semiconductor devices invented. It is a PNPN diode, with alternating layers of P-type and N-type material. It is equivalent to a thyristor with a disconnected gate. Shockley diodes were manufactured and marketed by Shockley Semiconductor Laboratory in the late 1950s. The Shockley diode has a negative resistance characteristic. It was largely superseded by the diac. Working Unlike other semiconductor diodes, the Shockley diode has more than one PN junction. The construction includes four sections of semiconductors placed alternately between the anode and cathode in the pattern of PNPN. Though it has multiple junctions, it is termed a diode for being a two-terminal device. The Shockley diode remains in an OFF state, with a very high resistance, until a voltage greater than the trigger voltage is applied across its terminals. When the voltage exceeds th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Impact Ionization
Impact ionization is the process in a material by which one energetic charge carrier can lose energy by the creation of other charge carriers. For example, in semiconductors, an electron (or Electron hole, hole) with enough kinetic energy can knock a bound electron out of its bound state (in the valence band) and promote it to a state in the conduction band, creating an electron-hole pair. For carriers to have sufficient kinetic energy a sufficiently large electric field must be applied, in essence requiring a sufficiently large voltage but not necessarily a large current. If this occurs in a region of high electrical field then it can result in avalanche breakdown. This process is exploited in avalanche diodes, by which a small optical signal is amplifier, amplified before entering an external electronic circuit. In an avalanche photodiode the original charge carrier is created by the absorption of a photon. The impact ionization process is used in modern cosmic dust detectors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Switch
In electrical engineering, a switch is an electrical component that can disconnect or connect the conducting path in an electrical circuit, interrupting the electric current or diverting it from one conductor to another. The most common type of switch is an electromechanical device consisting of one or more sets of movable electrical contacts connected to external circuits. When a pair of contacts is touching current can pass between them, while when the contacts are separated no current can flow. Switches are made in many different configurations; they may have multiple sets of contacts controlled by the same knob or actuator, and the contacts may operate simultaneously, sequentially, or alternately. A switch may be operated manually, for example, a light switch or a keyboard button, or may function as a sensing element to sense the position of a machine part, liquid level, pressure, or temperature, such as a thermostat. Many specialized forms exist, such as the toggle switch, ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
YAG Laser )
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YAG laser may refer to two types of lasers that use yttrium aluminum garnet (YAG): * Nd:YAG laser (doped with neodymium) * Er:YAG laser (doped with erbium Erbium is a chemical element with the symbol Er and atomic number 68. A silvery-white solid metal when artificially isolated, natural erbium is always found in chemical combination with other elements. It is a lanthanide, a rare-earth element, or ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Thyristor
A thyristor () is a solid-state semiconductor device with four layers of alternating P- and N-type materials used for high-power applications. It acts exclusively as a bistable switch (or a latch), conducting when the gate receives a current trigger, and continuing to conduct until the voltage across the device is reversed biased, or until the voltage is removed (by some other means). There are two designs, differing in what triggers the conducting state. In a three-lead thyristor, a small current on its Gate lead controls the larger current of the Anode to Cathode path. In a two-lead thyristor, conduction begins when the potential difference between the Anode and Cathode themselves is sufficiently large (breakdown voltage). Some sources define silicon-controlled rectifier (SCR) and thyristor as synonymous. Other sources define thyristors as more complex devices that incorporate at least four layers of alternating N-type and P-type substrate. The first thyristor devices were ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Arkady Melua
Arkady Ivanovich Melua (7 February 1950, Kazatin) is the general director and editor-in-chief of the scientific publishing house, Humanistica. Life and work Starting in 1969, Melua served and worked as an engineer at the Ministry of Defense facilities. In 1973, while having served in the military, he received a degree in engineering at the Leningrad Engineering-Construction Institute. He participated in the construction of an educational nuclear reactor in one of the military schools. In 1974, he began conducting scientific research. Melua was a member of the Soviet Union project of long-term lunar base (research leader - the chief designer of the Design Bureau of General Mechanical Engineering, Academician Vladimir Barmin, curator in Saint Petersburg - Professor N. Krylov). He was an author of one of the country's first lunar inventions of special facilities and research equipment. As a scientist, he was a secretary of the "lunar laboratory" in Leningrad and was involved i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electric Power Conversion
In all fields of electrical engineering, power conversion is the process of converting electric energy from one form to another. A power converter is an electrical or electro-mechanical device for converting electrical energy. A power converter can convert alternating current (AC) into direct current (DC) and vice versa; change the voltage or frequency of the current or do some combination of these. The power converter can be as simple as a transformer or it can be a far more complex system, such as resonant converter. The term can also refer to a class of electrical machinery that is used to convert one frequency of alternating current into another. Power conversion systems often incorporate redundancy and voltage regulation. Power converters are classified based on the type of power conversion they do. One way of classifying power conversion systems is according to whether the input and output are alternating current or direct current. Finally, the task of all power converte ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Power Electronics
Power electronics is the application of electronics to the control and conversion of electric power. The first high-power electronic devices were made using mercury-arc valves. In modern systems, the conversion is performed with semiconductor switching devices such as diodes, thyristors, and power transistors such as the power MOSFET and IGBT. In contrast to electronic systems concerned with the transmission and processing of signals and data, substantial amounts of electrical energy are processed in power electronics. An AC/DC converter (rectifier) is the most typical power electronics device found in many consumer electronic devices, e.g. television sets, personal computers, battery chargers, etc. The power range is typically from tens of watts to several hundred watts. In industry, a common application is the Adjustable-speed drive, variable speed drive (VSD) that is used to control an induction motor. The power range of VSDs starts from a few hundred watts and ends at tens ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solid-state Electronics
Solid-state electronics means semiconductor electronics: electronic equipment using semiconductor devices such as transistors, diodes and integrated circuits (ICs). The term is also used as an adjective for devices in which semiconductor electronics that have no moving parts replace devices with moving parts, such as the solid-state relay in which transistor switches are used in place of a moving-arm electromechanical relay, or the solid-state drive (SSD) a type of semiconductor memory used in computers to replace hard disk drives, which store data on a rotating disk. History The term "solid-state" became popular at the beginning of the semiconductor era in the 1960s to distinguish this new technology based on the transistor, in which the electronic action of devices occurred in a solid state, from previous electronic equipment that used vacuum tubes, in which the electronic action occurred in a gaseous state. A semiconductor device works by controlling an electric current ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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