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International Electrical Congress
The International Electrical Congress was a series of international meetings, from 1881 - 1904, in the then new field of applied electricity. The first meeting was initiated by the French government, including official national representatives, leading scientists, and others. Subsequent meetings also included official representatives, leading scientists, and others. Primary aims were to develop reliable standards, both in relation to electrical units and electrical apparatus. Historical background In 1881, both within and across countries, different electrical units were being used. There were at least 12 different units of electromotive force, 10 different units of electric current and 15 different units of resistance. A number of international Congresses were held, and sometimes referred to as International Electrical Congress, Electrical Conference, and similar variations. Secondary sources make different judgments about how to classify the Congresses. In this article, the Congr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrical Engineering
Electrical engineering is an engineering discipline concerned with the study, design, and application of equipment, devices, and systems which use electricity, electronics, and electromagnetism. It emerged as an identifiable occupation in the latter half of the 19th century after commercialization of the electric telegraph, the telephone, and electrical power generation, distribution, and use. Electrical engineering is now divided into a wide range of different fields, including computer engineering, systems engineering, power engineering, telecommunications, radio-frequency engineering, signal processing, instrumentation, photovoltaic cells, electronics, and optics and photonics. Many of these disciplines overlap with other engineering branches, spanning a huge number of specializations including hardware engineering, power electronics, electromagnetics and waves, microwave engineering, nanotechnology, electrochemistry, renewable energies, mechatronics/control, and electrical m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Farad
The farad (symbol: F) is the unit of electrical capacitance, the ability of a body to store an electrical charge, in the International System of Units (SI). It is named after the English physicist Michael Faraday (1791–1867). In SI base units 1 F = 1 kg−1⋅ m−2⋅ s4⋅ A2. Definition The capacitance of a capacitor is one farad when one coulomb of charge changes the potential between the plates by one volt. Equally, one farad can be described as the capacitance which stores a one-coulomb charge across a potential difference of one volt. The relationship between capacitance, charge, and potential difference is linear. For example, if the potential difference across a capacitor is halved, the quantity of charge stored by that capacitor will also be halved. For most applications, the farad is an impractically large unit of capacitance. Most electrical and electronic applications are covered by the following SI prefixes: *1 mF (millifarad, one thousandth ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Field
A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. A permanent magnet's magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets. In addition, a nonuniform magnetic field exerts minuscule forces on "nonmagnetic" materials by three other magnetic effects: paramagnetism, diamagnetism, and antiferromagnetism, although these forces are usually so small they can only be detected by laboratory equipment. Magnetic fields surround magnetized materials, and are created by electric currents such as those used in electromagnets, and by electric fields varying in time. Since both strength and direction of a magnetic field may vary with location, it is described mathematically by a function assigning a vector to each point of space, cal ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Flux Density
Flux describes any effect that appears to pass or travel (whether it actually moves or not) through a surface or substance. Flux is a concept in applied mathematics and vector calculus which has many applications to physics. For transport phenomena, flux is a vector quantity, describing the magnitude and direction of the flow of a substance or property. In vector calculus flux is a scalar quantity, defined as the surface integral of the perpendicular component of a vector field over a surface. Terminology The word ''flux'' comes from Latin: ''fluxus'' means "flow", and ''fluere'' is "to flow". As ''fluxion'', this term was introduced into differential calculus by Isaac Newton. The concept of heat flux was a key contribution of Joseph Fourier, in the analysis of heat transfer phenomena. His seminal treatise ''Théorie analytique de la chaleur'' (''The Analytical Theory of Heat''), defines ''fluxion'' as a central quantity and proceeds to derive the now well-known expres ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gauss (unit)
The gauss, symbol (sometimes Gs), is a unit of measurement of magnetic induction, also known as ''magnetic flux density''. The unit is part of the Gaussian system of units, which inherited it from the older CGS-EMU system. It was named after the German mathematician and physicist Carl Friedrich Gauss in 1936. One gauss is defined as one maxwell per square centimetre. As the cgs system has been superseded by the International System of Units (SI), the use of the gauss has been deprecated by the standards bodies, but is still regularly used in various subfields of science. The SI unit for magnetic flux density is the tesla (symbol T), which corresponds to . Name, symbol, and metric prefixes Albeit not a component of the International System of Units, the usage of the gauss generally follows the rules for SI units. Since the name is derived from a person's name, its symbol is the uppercase letter ''G''. When the unit is spelled out, it is written in lowercase ("gauss"), unless ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Field Intensity
A magnetic field is a vector field that describes the magnetic influence on moving electric charges, electric currents, and magnetic materials. A moving charge in a magnetic field experiences a force perpendicular to its own velocity and to the magnetic field. A permanent magnet's magnetic field pulls on ferromagnetic materials such as iron, and attracts or repels other magnets. In addition, a nonuniform magnetic field exerts minuscule forces on "nonmagnetic" materials by three other magnetic effects: paramagnetism, diamagnetism, and antiferromagnetism, although these forces are usually so small they can only be detected by laboratory equipment. Magnetic fields surround magnetized materials, and are created by electric currents such as those used in electromagnets, and by electric fields varying in time. Since both strength and direction of a magnetic field may vary with location, it is described mathematically by a function assigning a vector to each point of space, calle ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Maxwell (unit)
The maxwell (symbol: Mx) is the CGS (centimetre–gram–second) unit of magnetic flux (). History The unit name honours James Clerk Maxwell, who presented a unified theory of electromagnetism. The ''maxwell'' was recommended as a CGS unit at the International Electrical Congress held in 1900 at Paris. This practical unit was previously called a ''line'', reflecting Faraday's conception of the magnetic field as curved lines of magnetic force, which he designated as ''line of magnetic induction''. ''Kiloline'' (103 line) and ''megaline'' (106 line) were sometimes used because 1 line was very small relative to the phenomena that it was used to measure. The ''maxwell'' was affirmed again unanimously as the unit name for magnetic flux at the Plenary Meeting of the International Electrotechnical Commission (IEC) in July 1930 at Oslo. In 1933, the Electric and Magnetic Magnitudes and Units committee of the IEC recommended to adopt the metre–kilogram–second ( MKS) system (Giorgi s ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Magnetic Flux
In physics, specifically electromagnetism, the magnetic flux through a surface is the surface integral of the normal component of the magnetic field B over that surface. It is usually denoted or . The SI unit of magnetic flux is the weber (Wb; in derived units, volt–seconds), and the CGS unit is the maxwell. Magnetic flux is usually measured with a fluxmeter, which contains measuring coils and electronics, that evaluates the change of voltage in the measuring coils to calculate the measurement of magnetic flux. Description The magnetic interaction is described in terms of a vector field, where each point in space is associated with a vector that determines what force a moving charge would experience at that point (see Lorentz force). Since a vector field is quite difficult to visualize at first, in elementary physics one may instead visualize this field with field lines. The magnetic flux through some surface, in this simplified picture, is proportional to the num ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Éleuthère Mascart
Éleuthère Élie Nicolas Mascart (20 February 1837 – 24 August 1908) was a noted French physicist, a researcher in optics, electricity, magnetism, and meteorology. Life Mascart was born in Quarouble, Nord. Starting in 1858, he attended the École normale supérieure (rue d'Ulm), earning his '' agrégé-préparateur'' three years later. He acquired his doctoral degree in science in 1864. After serving at various posts in secondary education, in 1868 he moved to the Collège de France to become Henri Victor Regnault's assistant. Mascart was appointed to succeed Régnault as the tenured Régnault chair in 1872, which he held until his death. In 1878 he also became the first director of the Bureau Central Météorologique. He won the Bordin Prize of the Académie française in 1866 and the Grand prix of the Académie des sciences in 1874. He was elected as a member of the American Philosophical Society in 1890. He was elected Perpetual Member (1884), Secretary, and i ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Paris Exposition Universelle
The Exposition Universelle of 1889 () was a world's fair held in Paris, France, from 5 May to 31 October 1889. It was the fourth of eight expositions held in the city between 1855 and 1937. It attracted more than thirty-two million visitors. The most famous structure created for the Exposition, and still remaining, is the Eiffel Tower. Organization The Exposition was held to celebrate the 100th anniversary of the Storming of the Bastille, which marked the beginning of French Revolution, and was also seen as a way to stimulate the economy and pull France out of an economic recession. The Exposition attracted 61,722 official exhibitors, of whom twenty-five thousand were from outside of France. Admission price Admission to the Exposition cost forty centimes, at a time when the price of an "economy" plate of meat and vegetables in a Paris cafe was ten centimes. Visitors paid an additional price for several of the Exposition's most popular attractions. Climbing the Eiffel Towe ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
International System Of Electrical And Magnetic Units
The International System of Electrical and Magnetic Units is an obsolete system of units used for measuring electrical and magnetic quantities. It was proposed as a system of practical international units by unanimous recommendation at the International Electrical Congress (Chicago, 1893), discussed at other Congresses, and finally adopted at the International Conference on Electric Units and Standards in London in 1908. It was rendered obsolete by the inclusion of electromagnetic units in the International System of Units (SI) at the 9th General Conference on Weights and Measures in 1948. Earlier systems The link between electromagnetic units and the more familiar units of length, mass and time was first demonstrated by Carl Friedrich Gauss in 1832 with his measurement of the Earth's magnetic field, and the principle was extended to electrical measurements by Franz Ernst Neumann in 1845. A complete system of metric electrical and magnetic units was proposed by Wilhelm Eduard We ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
