Glow discharge current-voltage curve English

An electric discharge is the release and transmission of electricity in an applied electric field through a medium such as a gas (ie., an outgoing flow of

electric current An electric current is a stream of charged particles, such as electrons or ions, moving through an electrical conductor or space. It is measured as the net rate of flow of electric charge through a surface or into a control volume. The movin ...

through a non-

metal A metal (from Greek μέταλλον ''métallon'', "mine, quarry, metal") is a material that, when freshly prepared, polished, or fractured, shows a lustrous appearance, and conducts electricity and heat relatively well. Metals are typi ...

medium).American Geophysical Union, National Research Council (U.S.). Geophysics Study Committee (1986) ''The earth's electrical environment''. National Academy Press, Washington, DC, p. 263.

Applications

The properties and effects of electric discharges are useful over a wide range of magnitudes. Tiny pulses of current are used to detect ionizing radiation in a Geiger–Müller tube. A low steady current can be used to illustrate the spectrum of gases in a

gas-filled tube A gas-filled tube, also commonly known as a discharge tube or formerly as a Plücker tube, is an arrangement of electrodes in a gas within an insulating, temperature-resistant envelope. Gas-filled tubes exploit phenomena related to electric ...

. A neon lamp is an example of a gas-discharge lamp, useful both for illumination and as a voltage regulator. A

flashtube A flashtube (flashlamp) is an electric arc lamp designed to produce extremely intense, Coherence (physics), incoherent, full-spectrum white light for a very short time. A flashtube is a glass tube with an electrode at each end and is filled with ...

generates a short pulse of intense light useful for

photography Photography is the visual art, art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It i ...

by sending a heavy current through a gas arc discharge. Corona discharges are used in

photocopier A photocopier (also called copier or copy machine, and formerly Xerox machine, the generic trademark) is a machine that makes copies of documents and other visual images onto paper or plastic film quickly and cheaply. Most modern photocopiers u ...

s. Electric discharges can convey substantial energy to the electrodes at the ends of the discharge. A spark gap is used in internal combustion engines to ignite the fuel/air mixture on every power stroke. Spark gaps are also used to switch heavy currents in a Marx generator and to protect electrical apparatus. In

electric discharge machining Electrical discharge machining (EDM), also known as spark machining, spark eroding, die sinking, wire burning or wire erosion, is a metal fabrication process whereby a desired shape is obtained by using electrical discharges (sparks). Material i ...

, multiple tiny electric arcs are used to erode a conductive workpiece to a finished shape.

Arc welding Arc welding is a welding process that is used to join metal to metal by using electricity to create enough heat to melt metal, and the melted metals, when cool, result in a binding of the metals. It is a type of welding that uses a welding po ...

is used to assemble heavy steel structures, where the base metal is heated to melting by the heat of the arc. An

electric arc furnace An electric arc furnace (EAF) is a furnace that heats material by means of an electric arc. Industrial arc furnaces range in size from small units of approximately one-tonne capacity (used in foundries for producing cast iron products) up to ...

sustains arc currents of tens of thousands of amperes and is used for steelmaking and production of alloys and other products.

Examples

Examples of electric discharge phenomena include: * Brush discharge *

Dielectric barrier discharge Dielectric-barrier discharge (DBD) is the electrical discharge between two electrodes separated by an insulating dielectric barrier. Originally called silent (inaudible) discharge and also known as ozone production discharge or partial dischar ...

* Corona discharge * Electric glow discharge * Electric arc * Electrostatic discharge * Electric discharge in gases *

Leader (spark) A leader is a hot, highly conductive channel of plasma that plays a critical part during dielectric breakdown within a long electric spark. Mechanism When a gas is subjected to high voltage stress, the electric field is often quite non-unifor ...

* Partial discharge * Streamer discharge *

Vacuum arc A vacuum arc can arise when the surfaces of metal electrodes in contact with a good vacuum begin to emit electrons either through heating (thermionic emission) or in an electric field that is sufficient to cause field electron emission. Once initia ...

Townsend discharge The Townsend discharge or Townsend avalanche is a gas ionisation process where free electrons are accelerated by an electric field, collide with gas molecules, and consequently free additional electrons. Those electrons are in turn accelerated a ...

* St. Elmo's fire *

Lightning Lightning is a naturally occurring electrostatic discharge during which two electrically charged regions, both in the atmosphere or with one on the ground, temporarily neutralize themselves, causing the instantaneous release of an average ...

* Electric organ

References

Electrical phenomena Plasma physics {{plasma-stub

Applications

Examples

See also

References