electric arc
Information about electric arc
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A 3000 volt electricity arc between two nails
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Electricity arcs between the power rail and electrical pickup "shoe" on a London Underground train
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An electric arc can melt calcium oxide
An electric arc is an electrical breakdown of a gas which produces an ongoing plasma discharge, resulting from a current flowing through normally nonconductive media such as air. A synonym is arc discharge. The phenomenon was first described by Vasily V. Petrov (), a Russian scientist who discovered it in 1802. An archaic term is voltaic arc as used in the phrase "voltaic arc lamp".
The various shapes of electric arc are emergent properties of nonlinear patterns of current and electric field. The arc occurs in the gas-filled space between two conductive electrodes (often made of carbon) and it results in a very high temperature, capable of melting or vaporizing most materials. An electric arc is a continuous discharge, while a similar electric spark discharge is momentary. An electric arc may occur either in direct-current circuits or in alternating current circuits. In the latter case, the arc may re-strike on each half cycle of the current. An electric arc differs from a glow discharge in that the current density is quite high, and the voltage drop within the arc is low; at the cathode the current density may be as high as one million amps per square centimeter. [1]
On a commercial basis, electric arcs are used for welding, plasma cutting, for electrical discharge machining, as an arc lamp in movie theater projectors and Followspots in stage lighting. Electric arc furnaces are used to produce steel and other substances. Calcium carbide is made in this way as it requires a large amount of energy to promote an endothermic reaction (at temperatures of 2500 °C).
Low-pressure electric arcs are used for lighting, e.g., fluorescent tubes, mercury and sodium street lamps, and camera flash lamps.
Undesired or unintended electric arcing can have detrimental effects on electric power transmission and distribution systems and electronic equipment.
An electric arc has a non-linear relationship between current and voltage. Once the arc is established (either by progression from a glow discharge or by momentarily touching the electrodes then separating them), increased current results in a lower voltage between the arc terminals. This negative impedance effect requires that some positive form of impedance to be placed in the circuit, if it is desired to maintain a stable arc. This property is the reason uncontrolled electrical arcs in apparatus become so destructive, since once initiated an arc will draw more and more current from a fixed-volage supply until the apparatus is destroyed.
See also
References
External links
- Arc Analysis
- Unusual Arcing Photos
- Some more info about making electric arcs using a welder.
- Videos of 230,000 volt 3-phase "Jacobs Ladder" and unintentional 500,000 volt power arc
electrical breakdown has several similar but distinctly different meanings. The term may apply to a failure of an electric circuit or system with consequent lack of function.
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plasma is typically an ionized gas. Plasma is considered to be a distinct state of matter, apart from gases, because of its unique properties. "Ionized" refers to presence of one or more free electrons, which are not bound to an atom or molecule.
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Electrostatic discharge (ESD) is the sudden and momentary electric current that flows between two objects at different electrical potentials. The term is usually used in the electronics and other industries to describe momentary unwanted currents that may cause damage to
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Electrical conductance is the reciprocal of electrical resistance. It is a measure of how easily electricity flows along a certain path through an electrical element. The SI derived unit of conductance is the siemens (formerly referred to as the reciprocal ohm or mho).
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Air or Earth's atmosphere is a layer of gases surrounding the planet Earth.
Air may also refer to:
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Air may also refer to:
- Air (1977 video game), an air combat based mainframe computer game
- Air (band), a French electronic music duo
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Vasily Vladimirovich Petrov (Russian: Василий Владимирович Петров) (19 July [O.S.
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8th century - 9th century - 10th century
850s 860s 870s - 880s - 890s 900s 910s
885 886 887 - 888 - 889 890 891
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Subjects: Archaeology - Architecture -
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850s 860s 870s - 880s - 890s 900s 910s
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Subjects: Archaeology - Architecture -
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emergence refers to the way complex systems and patterns arise out of a multiplicity of relatively simple interactions. Like intelligence in the field of AI, or agents in distributed artificial intelligence, emergence is central to the theory of complex systems and yet very
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Electric current is the flow (movement) of electric charge. The SI unit of electric current is the ampere (A), which is equal to a flow of one coulomb of charge per second.
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Definition
The amount of electric current (measured in amperes) through some surface, e.g...... Click the link for more information.
electric field. This electric field exerts a force on other electrically charged objects. The concept of electric field was introduced by Michael Faraday.
The electric field is a vector field with SI units of newtons per coulomb (N C−1
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The electric field is a vector field with SI units of newtons per coulomb (N C−1
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An electrode is an electrical conductor used to make contact with a nonmetallic part of a circuit (e.g. a semiconductor, an electrolyte or a vacuum). The word was coined by the scientist Michael Faraday from the Greek words elektron
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4, 2
(mildly acidic oxide)
Electronegativity 2.55 (Pauling scale)
Ionization energies
(more) 1st: 1086.5 kJmol−1
2nd: 2352.6 kJmol−1
3rd: 4620.5 kJmol−1
Atomic radius 70 pm
Atomic radius (calc.
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(mildly acidic oxide)
Electronegativity 2.55 (Pauling scale)
Ionization energies
(more) 1st: 1086.5 kJmol−1
2nd: 2352.6 kJmol−1
3rd: 4620.5 kJmol−1
Atomic radius 70 pm
Atomic radius (calc.
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trillion fold).]]
Temperature is a physical property of a system that underlies the common notions of hot and cold; something that is hotter generally has the greater temperature. Temperature is one of the principal parameters of thermodynamics.
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Temperature is a physical property of a system that underlies the common notions of hot and cold; something that is hotter generally has the greater temperature. Temperature is one of the principal parameters of thermodynamics.
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Melting is a process that results in the phase change of a substance from a solid to a liquid. The internal energy of a solid substance is increased (typically by the application of heat) to a specific temperature (called the melting point) at which it changes to the liquid phase.
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Evaporation is the process by which molecules in a liquid state (e.g. water) spontaneously become gaseous (e.g. water vapor), without being heated to boiling point. It is the opposite of condensation.
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The word spark has several meanings:
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- In electricity, "spark" usually refers to a momentary electrostatic discharge across a spark gap. It can also refer to a continuous electric arc or a corona discharge.
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Electric glow discharge is a type of plasma formed by passing a current at 100 V to several kV through a gas, usually argon or another noble gas. It is found in products such as fluorescent lights and plasma-screen televisions, and is used in plasma physics and analytical chemistry.
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A cathode is an electrode through which (positive) electric current flows out of a polarized electrical device. Mnemonic: CCD (Cathode Current Departs). To dispel a common misconception, often incorrectly inferred from the correct fact that in all electrochemical
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Welding is a fabrication process that joins materials, usually metals or thermoplastics, by causing coalescence. This is often done by melting the workpieces and adding a filler material to form a pool of molten material (the weld puddle
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Plasma cutting is a process that is used to cut steel and other metals (or sometimes other materials) using a plasma torch. In this process, an inert gas (in some units, compressed air) is blown at high speed out of a nozzle; at the same time an electrical arc is formed through
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Electrical discharge machining (or EDM) is a machining method primarily used for hard metals or those that would be impossible to machine with traditional techniques.
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arc lamp is the general term for a class of lamps that produce light by an electric arc (or voltaic arc). The lamp consists of two electrodes typically made of tungsten which are separated by a gas.
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movie projector is an opto-mechanical device for displaying moving pictures by projecting them on a projection screen. Most of the optical and mechanical elements, except for the illumination and sound devices, are present in movie cameras.
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A followspot, sometimes known as a spotlight, is a powerful stage light which can be controlled by a human spotlight operator to "follow" actors around the stage. Followspots are commonly used in concerts, musical theatre and opera to highlight the stars of a performance,
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Stagecraft collaboration!
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Modern stage lighting is a flexible tool in the production of theatre, dance, opera and other performance arts.
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An electric arc furnace (EAF) is a furnace that heats charged material by means of an electric arc.
Arc furnaces range in size from small units of approximately one ton capacity (used in foundries for producing cast iron products) up to about 400 ton units used for secondary
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Arc furnaces range in size from small units of approximately one ton capacity (used in foundries for producing cast iron products) up to about 400 ton units used for secondary
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Steel is an alloy consisting mostly of iron, with a carbon content between 0.02% and 1.7 or 2.04% by weight (C:1000–10,8.67Fe), depending on grade. Carbon is the most cost-effective alloying material for iron, but various other alloying elements are used such as manganese and
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Calcium carbide is a chemical compound with the chemical formula CaC2. Its appearance depends on the grade and ranges from black through to grayish white lumps. Its main use now is as a source of acetylene.
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endothermic describes a process or reaction that absorbs energy in the form of heat. Its etymology stems from the Greek prefix endo-, meaning “inside” and the Greek suffix –thermic, meaning “to heat”.
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chemical reaction is a process that results in the interconversion of chemical substances.[1] The substance or substances initially involved in a chemical reaction are called reactants.
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