# arc

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## arc,

in electricity, highly luminous and intensely hot discharge of electricity between two electrodes. The arc was discovered early in the 19th cent. by the English scientist Sir Humphry Davy, who so named it because of its shape. An arc is characterized by a high current, low voltage, and indefinite duration. It is usually started when two electrodes carrying an electric current are drawn apart. At the instant the electrodes are parted, strong electric forces draw electrons from one electrode to the other, initiating the arc. The discharge consists of a current composed of these electrons and charged gas particles, called ions, that form between the electrodes. The first practical electric light, the arc lamp, made use of the arc formed between two carbon rods (see lightinglighting,
light produced by artificial means to allow visibility in enclosures and at night. For stage lighting, see scene design and stage lighting. Early Sources of Artificial Lighting
). Today the use of the arc lamp is limited to special purposes, e.g., in searchlights and in research applications. The principle of the electric arc is employed in weldingwelding,
process for joining separate pieces of metal in a continuous metallic bond. Cold-pressure welding is accomplished by the application of high pressure at room temperature; forge welding (forging) is done by means of hammering, with the addition of heat.
(as in the hydrogen arc, where hydrogen is introduced between tungsten electrodes) and also in generating heat in the electric furnace. A spark, like an arc, is a discharge of electricity between two points, but it has a high voltage and a short duration. Lightning is an example of a spark.

## arc,

in geometry, a curved line or any part of it; in particular, a portion of the circumference of a circle. The length s of an arc of a circle of radius r and subtending a central angle of θ radians is s=rθ; if θ is measured in degrees, then the arc is given by s=2πrθ/360.

## ARC

Abbrev. for Astrophysical Research Consortium. See Apache Point Observatory.
Collins Dictionary of Astronomy © Market House Books Ltd, 2006
The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

## Arc

(also called simple arc or Jordan arc), a part of a curve that is contained between two of its points and does not have multiple points. The arc is more accurately defined on a plane, with the coordinates of its points being given as the continuous functions x = φ(t) and y = ψt of some parameter t, atb. It is assumed that the different points correspond to the different values of t.

## arc

[ärk]
(electricity)
(engineering)
The graduated scale of an instrument for measuring angles, as a marine sextant; readings obtained on that part of the arc beginning at zero and extending in the direction usually considered positive are popularly said to be on the arc, and those beginning at zero and extending in the opposite direction are said to be off the arc.
(geology)
A geologic or topographic feature that is repeated along a curved line on the surface of the earth.
(mathematics)
A continuous piece of the circumference of a circle.

## Arc

[ärk]
(astronomy)
A radio source consisting of two bundles of parallel filaments adjoining the source Sagittarius A near the center of the Milky Way Galaxy.

## ARC

AIDS-related complex
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.

## arc

1. The luminous column of gas in an arc discharge; caused by the flow of electric current between separated electrodes in a gas.
3. Any part of the circumference of a circle.
4. An angular measure.
McGraw-Hill Dictionary of Architecture and Construction. Copyright © 2003 by McGraw-Hill Companies, Inc.

## arc

The track over ground of an aircraft flying at a constant distance from a navigational aid by reference to distance-measuring equipment.

## arc

1. a luminous discharge that occurs when an electric current flows between two electrodes or any other two surfaces separated by a small gap and a high potential difference
2. Astronomy a circular section of the apparent path of a celestial body
3. Maths a section of a curve, graph, or geometric figure

## ARC

AIDS-related complex: an early condition in which a person infected with the AIDS virus may suffer from such mild symptoms as loss of weight, fever, etc.
Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

(1)

## arc

(file format, tool)
An old archive format for IBM PC. The format is now so obscure that it is only likely to be supported by jack-of-all-trades decompression programs such as WINZIP.

## arc

(mathematics, data)
An edge in a tree. "branch" is a generally more common synonym.

## ARC

(1) (Audio Return Channel) See HDMI ARC.

(2) PC compression programs from System Enhancement Associates, Inc., Clifton, NJ. ARC was one of the first compression utilities to become popular in the early 1980s. ARC+Plus provides enhanced features and speed.

(3) The ARC extension was previously used by PKWARE Inc. in its PKARC program.

(4) (Advanced RISC Computing) An earlier open system specification based on the MIPS R3000 and R4000 CPUs. It included EISA and TURBOchannel buses.
Copyright © 1981-2019 by The Computer Language Company Inc. All Rights reserved. THIS DEFINITION IS FOR PERSONAL USE ONLY. All other reproduction is strictly prohibited without permission from the publisher.
References in periodicals archive ?
Kate Shankley, from Arc, talking to Abbey National's Keith Bowran
Work is progressing to promote ARC nursing as a practice setting for new graduates and to reduce variability in the NETP experience.
In a strong criticism of Arc's actions, trainer Ralph Beckett said: "It shows Arc in their true colours.
These methods monitor continually current and voltage signals in circuits and search the characteristics of arc faults.
Our program collects a tax-free donation as small as 50 cents, adds a matching donation from ARC, and uses the money to plant trees in certified reforestation programs around the world.
The drilling contractor has agreed to only trade a certain volume of the shares, which Arc said it will monitor.
ARC provides technology and document solutions for every stage of the building lifecycle--from design to build to operate.
Arc flashes can reach 35,000 F and their intense light is capable of severely damaging the human eye.
Top sees for a fee The 200 kilometres of slopes in Les Arcs have something to suit every skill level, from its smooth, easy trails to its 17 black runs.
An arc is usually an initial approach segment charted as a heavy black line, making it part of the approach.
ARC Specialty, meanwhile, will continue to operate in the wholesale space along with its MGU, Professionals Risk Facilities, Inc.

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