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# Electric current

An electric current is a flow of electric charge. 

170 relations: Absolute zero, AC power, Alternating current, Ammeter, Ampère's force law, Ampere, André-Marie Ampère, Anisotropy, Antenna (radio), Archaism, Atomic nucleus, Atomic orbital, Audio frequency, Aurora, Avalanche breakdown, Band gap, Cambridge University Press, Cathode ray, Cathode ray tube, Charge carrier, Charge density, Chlorine, Classical physics, Cold cathode, Commutator (electric), Convection, Copper, Coulomb, Critical point (thermodynamics), Cryogenics, Current clamp, Current density, Current sensing techniques, Current transformer, Dielectric, Direct current, Dopant, Drift velocity, Dynamo, Eddy current, Electric arc, Electric battery, Electric charge, Electric current, Electric field, Electric potential, Electric power, Electric power transmission, Electric spark, Electrical breakdown, ... Expand index (120 more) »

## Absolute zero

Absolute zero is the lower limit of the thermodynamic temperature scale, a state at which the enthalpy and entropy of a cooled ideal gas reach their minimum value, taken as 0.

## AC power

Power in an electric circuit is the rate of flow of energy past a given point of the circuit.

## Alternating current

Alternating current (AC) is an electric current which periodically reverses direction, in contrast to direct current (DC) which flows only in one direction.

## Ammeter

An ammeter (from Ampere Meter) is a measuring instrument used to measure the current in a circuit.

## Ampère's force law

In magnetostatics, the force of attraction or repulsion between two current-carrying wires (see first figure below) is often called Ampère's force law.

## Ampere

The ampere (symbol: A), often shortened to "amp",SI supports only the use of symbols and deprecates the use of abbreviations for units.

## André-Marie Ampère

André-Marie Ampère (20 January 177510 June 1836) was a French physicist and mathematician who was one of the founders of the science of classical electromagnetism, which he referred to as "electrodynamics".

## Anisotropy

Anisotropy, is the property of being directionally dependent, which implies different properties in different directions, as opposed to isotropy.

In radio, an antenna is the interface between radio waves propagating through space and electric currents moving in metal conductors, used with a transmitter or receiver.

## Archaism

In language, an archaism (from the ἀρχαϊκός, archaïkós, 'old-fashioned, antiquated', ultimately ἀρχαῖος, archaîos, 'from the beginning, ancient') is the use of a form of speech or writing that is no longer current or that is current only within a few special contexts.

## Atomic nucleus

The atomic nucleus is the small, dense region consisting of protons and neutrons at the center of an atom, discovered in 1911 by Ernest Rutherford based on the 1909 Geiger–Marsden gold foil experiment.

## Atomic orbital

In quantum mechanics, an atomic orbital is a mathematical function that describes the wave-like behavior of either one electron or a pair of electrons in an atom.

## Audio frequency

An audio frequency (abbreviation: AF) or audible frequency is characterized as a periodic vibration whose frequency is audible to the average human.

## Aurora

An aurora (plural: auroras or aurorae), sometimes referred to as polar lights, northern lights (aurora borealis) or southern lights (aurora australis), is a natural light display in the Earth's sky, predominantly seen in the high-latitude regions (around the Arctic and Antarctic).

## Avalanche breakdown

Avalanche breakdown is a phenomenon that can occur in both insulating and semiconducting materials.

## Band gap

In solid-state physics, a band gap, also called an energy gap or bandgap, is an energy range in a solid where no electron states can exist.

## Cambridge University Press

Cambridge University Press (CUP) is the publishing business of the University of Cambridge.

## Cathode ray

Cathode rays (also called an electron beam or e-beam) are streams of electrons observed in vacuum tubes.

## Cathode ray tube

The cathode ray tube (CRT) is a vacuum tube that contains one or more electron guns and a phosphorescent screen, and is used to display images.

## Charge carrier

In physics, a charge carrier is a particle free to move, carrying an electric charge, especially the particles that carry electric charges in electrical conductors.

## Charge density

In electromagnetism, charge density is a measure of the amount of electric charge per unit length, surface area, or volume.

## Chlorine

Chlorine is a chemical element with symbol Cl and atomic number 17.

## Classical physics

Classical physics refers to theories of physics that predate modern, more complete, or more widely applicable theories.

## Cold cathode

A cold cathode is a cathode that is not electrically heated by a filament.

## Commutator (electric)

A commutator is a rotary electrical switch in certain types of electric motors and electrical generators that periodically reverses the current direction between the rotor and the external circuit.

## Convection

Convection is the heat transfer due to bulk movement of molecules within fluids such as gases and liquids, including molten rock (rheid).

## Copper

Copper is a chemical element with symbol Cu (from cuprum) and atomic number 29.

## Coulomb

The coulomb (symbol: C) is the International System of Units (SI) unit of electric charge.

## Critical point (thermodynamics)

In thermodynamics, a critical point (or critical state) is the end point of a phase equilibrium curve.

## Cryogenics

In physics, cryogenics is the production and behaviour of materials at very low temperatures.

## Current clamp

In electrical and electronic engineering, a current clamp or current probe is an electrical device with jaws which open to allow clamping around an electrical conductor.

## Current density

In electromagnetism, current density is the electric current per unit area of cross section.

## Current sensing techniques

In electrical engineering, current sensing is any one of several techniques used to measure electric current.

## Current transformer

A current transformer (CT) is a type of transformer that is used to measure alternating current (AC).

## Dielectric

A dielectric (or dielectric material) is an electrical insulator that can be polarized by an applied electric field.

## Direct current

Direct current (DC) is the unidirectional flow of electric charge.

## Dopant

A dopant, also called a doping agent, is a trace impurity element that is inserted into a substance (in very low concentrations) to alter the electrical or optical properties of the substance.

## Drift velocity

The drift velocity is the average velocity that a particle, such as an electron, attains in a material due to an electric field.

## Dynamo

A dynamo is an electrical generator that creates direct current using a commutator.

## Eddy current

Eddy currents (also called Foucault currents) are loops of electrical current induced within conductors by a changing magnetic field in the conductor due to Faraday's law of induction.

## Electric arc

An electric arc, or arc discharge, is an electrical breakdown of a gas that produces an ongoing electrical discharge.

## Electric battery

An electric battery is a device consisting of one or more electrochemical cells with external connections provided to power electrical devices such as flashlights, smartphones, and electric cars.

## Electric charge

Electric charge is the physical property of matter that causes it to experience a force when placed in an electromagnetic field.

## Electric current

An electric current is a flow of electric charge.

## Electric field

An electric field is a vector field surrounding an electric charge that exerts force on other charges, attracting or repelling them.

## Electric potential

An electric potential (also called the electric field potential, potential drop or the electrostatic potential) is the amount of work needed to move a unit positive charge from a reference point to a specific point inside the field without producing any acceleration.

## Electric power

Electric power is the rate, per unit time, at which electrical energy is transferred by an electric circuit.

## Electric power transmission

Electric power transmission is the bulk movement of electrical energy from a generating site, such as a power plant, to an electrical substation.

## Electric spark

An electric spark is an abrupt electrical discharge that occurs when a sufficiently high electric field creates an ionized, electrically conductive channel through a normally-insulating medium, often air or other gases or gas mixtures.

## Electrical breakdown

Electrical breakdown or dielectric breakdown is when current flows through an electrical insulator when the voltage applied across it exceeds the breakdown voltage.

## Electrical conductor

In physics and electrical engineering, a conductor is an object or type of material that allows the flow of an electrical current in one or more directions.

## Electrical injury

Electrical injury is a physiological reaction caused by electric current passing through the (human) body.

An electrical load is an electrical component or portion of a circuit that consumes (active) electric power.

## Electrical measurements

Electrical measurements are the methods, devices and calculations used to measure electrical quantities.

## Electrical network

An electrical network is an interconnection of electrical components (e.g. batteries, resistors, inductors, capacitors, switches) or a model of such an interconnection, consisting of electrical elements (e.g. voltage sources, current sources, resistances, inductances, capacitances).

## Electrical polarity

Electrical polarity is a term used throughout industries and fields that involve electricity.

## Electrical resistance and conductance

The electrical resistance of an electrical conductor is a measure of the difficulty to pass an electric current through that conductor.

## Electrical resistivity and conductivity

Electrical resistivity (also known as resistivity, specific electrical resistance, or volume resistivity) is a fundamental property that quantifies how strongly a given material opposes the flow of electric current.

## Electrochemical cell

An electrochemical cell (EC) is a device capable of either generating electrical energy from chemical reactions or using electrical energy to cause chemical reactions.

## Electrochemistry

Electrochemistry is the branch of physical chemistry that studies the relationship between electricity, as a measurable and quantitative phenomenon, and identifiable chemical change, with either electricity considered an outcome of a particular chemical change or vice versa.

## Electrolyte

An electrolyte is a substance that produces an electrically conducting solution when dissolved in a polar solvent, such as water.

In physics, electromagnetic radiation (EM radiation or EMR) refers to the waves (or their quanta, photons) of the electromagnetic field, propagating (radiating) through space-time, carrying electromagnetic radiant energy.

## Electromagnetism

Electromagnetism is a branch of physics involving the study of the electromagnetic force, a type of physical interaction that occurs between electrically charged particles.

## Electromotive force

Electromotive force, abbreviated emf (denoted \mathcal and measured in volts), is the electrical intensity or "pressure" developed by a source of electrical energy such as a battery or generator.

## Electron

The electron is a subatomic particle, symbol or, whose electric charge is negative one elementary charge.

## Electron hole

In physics, chemistry, and electronic engineering, an electron hole (often simply called a hole) is the lack of an electron at a position where one could exist in an atom or atomic lattice.

## Electronics

Electronics is the discipline dealing with the development and application of devices and systems involving the flow of electrons in a vacuum, in gaseous media, and in semiconductors.

## Electronvolt

In physics, the electronvolt (symbol eV, also written electron-volt and electron volt) is a unit of energy equal to approximately joules (symbol J).

## Electrostatic discharge

Electrostatic discharge (ESD) is the sudden flow of electricity between two electrically charged objects caused by contact, an electrical short, or dielectric breakdown.

## Elementary charge

The elementary charge, usually denoted as or sometimes, is the electric charge carried by a single proton, or equivalently, the magnitude of the electric charge carried by a single electron, which has charge.

## Energy

In physics, energy is the quantitative property that must be transferred to an object in order to perform work on, or to heat, the object.

## Euclidean vector

In mathematics, physics, and engineering, a Euclidean vector (sometimes called a geometric or spatial vector, or—as here—simply a vector) is a geometric object that has magnitude (or length) and direction.

## Fermi gas

A Fermi gas is a phase of matter which is an ensemble of a large number of non-interacting fermions.

## Ferromagnetism

Ferromagnetism is the basic mechanism by which certain materials (such as iron) form permanent magnets, or are attracted to magnets.

## Fick's laws of diffusion

Fick's laws of diffusion describe diffusion and were derived by Adolf Fick in 1855.

## Field electron emission

Field electron emission (also known as field emission (FE) and electron field emission) is emission of electrons induced by an electrostatic field.

## Galvanometer

A galvanometer is an electromechanical instrument used for detecting and indicating electric current.

## Gas

Gas is one of the four fundamental states of matter (the others being solid, liquid, and plasma).

## George Gamow

George Gamow (March 4, 1904- August 19, 1968), born Georgiy Antonovich Gamov, was a Russian-American theoretical physicist and cosmologist.

## Hall effect

The Hall effect is the production of a voltage difference (the Hall voltage) across an electrical conductor, transverse to an electric current in the conductor and to an applied magnetic field perpendicular to the current.

## Heat

In thermodynamics, heat is energy transferred from one system to another as a result of thermal interactions.

## Heike Kamerlingh Onnes

Professor Heike Kamerlingh Onnes FRSFor HFRSE FCS (21 September 1853 – 21 February 1926) was a Dutch physicist and Nobel laureate.

## Hot cathode

In vacuum tubes and gas-filled tubes, a hot cathode or thermionic cathode is a cathode electrode which is heated to make it emit electrons due to thermionic emission.

## Hydraulic analogy

The electronic&ndash;hydraulic analogy (derisively referred to as the drain-pipe theory by Oliver Lodge) is the most widely used analogy for "electron fluid" in a metal conductor.

## Incandescent light bulb

An incandescent light bulb, incandescent lamp or incandescent light globe is an electric light with a wire filament heated to such a high temperature that it glows with visible light (incandescence).

## Insulator (electricity)

An electrical insulator is a material whose internal electric charges do not flow freely; very little electric current will flow through it under the influence of an electric field.

## International System of Quantities

The International System of Quantities (ISQ) is a system based on seven base quantities: length, mass, time, electric current, thermodynamic temperature, amount of substance, and luminous intensity.

## International System of Units

The International System of Units (SI, abbreviated from the French Système international (d'unités)) is the modern form of the metric system, and is the most widely used system of measurement.

## Ion

An ion is an atom or molecule that has a non-zero net electrical charge (its total number of electrons is not equal to its total number of protons).

## Ionization

Ionization or ionisation, is the process by which an atom or a molecule acquires a negative or positive charge by gaining or losing electrons to form ions, often in conjunction with other chemical changes.

## James Prescott Joule

James Prescott Joule (24 December 1818 11 October 1889) was an English physicist, mathematician and brewer, born in Salford, Lancashire.

## Joule

The joule (symbol: J) is a derived unit of energy in the International System of Units.

## Joule heating

Joule heating, also known as Ohmic heating and resistive heating, is the process by which the passage of an electric current through a conductor produces heat.

## Krytron

The krytron is a cold-cathode gas-filled tube intended for use as a very high-speed switch, somewhat similar to the thyratron.

## Leiden

Leiden (in English and archaic Dutch also Leyden) is a city and municipality in the province of South Holland, Netherlands.

## Light

Light is electromagnetic radiation within a certain portion of the electromagnetic spectrum.

## Lightning

Lightning is a sudden electrostatic discharge that occurs typically during a thunderstorm.

## Magnetic field

A magnetic field is a vector field that describes the magnetic influence of electrical currents and magnetized materials.

## Magnetoresistance

Magnetoresistance is the tendency of a material (preferably ferromagnetic) to change the value of its electrical resistance in an externally-applied magnetic field.

## Mass

Mass is both a property of a physical body and a measure of its resistance to acceleration (a change in its state of motion) when a net force is applied.

## Maxwell's equations

Maxwell's equations are a set of partial differential equations that, together with the Lorentz force law, form the foundation of classical electromagnetism, classical optics, and electric circuits.

## Meissner effect

The Meissner effect (or Meissner–Ochsenfeld effect) is the expulsion of a magnetic field from a superconductor during its transition to the superconducting state.

## Metal

A metal (from Greek μέταλλον métallon, "mine, quarry, metal") is a material (an element, compound, or alloy) that is typically hard when in solid state, opaque, shiny, and has good electrical and thermal conductivity.

## Minute

The minute is a unit of time or angle.

## Modulation

In electronics and telecommunications, modulation is the process of varying one or more properties of a periodic waveform, called the carrier signal, with a modulating signal that typically contains information to be transmitted.

## Molecule

A molecule is an electrically neutral group of two or more atoms held together by chemical bonds.

## Nanowire

A nanowire is a nanostructure, with the diameter of the order of a nanometer (10−9 meters).

## Neuron

A neuron, also known as a neurone (British spelling) and nerve cell, is an electrically excitable cell that receives, processes, and transmits information through electrical and chemical signals.

## Ohm

The ohm (symbol: Ω) is the SI derived unit of electrical resistance, named after German physicist Georg Simon Ohm.

## Ohm's law

Ohm's law states that the current through a conductor between two points is directly proportional to the voltage across the two points.

## Ohmic contact

An ohmic contact is a non-rectifying electrical junction: a junction between two conductors that has a linear current–voltage (I-V) curve as with Ohm's law.

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## Ozone

Ozone, or trioxygen, is an inorganic molecule with the chemical formula.

## Pauli exclusion principle

The Pauli exclusion principle is the quantum mechanical principle which states that two or more identical fermions (particles with half-integer spin) cannot occupy the same quantum state within a quantum system simultaneously.

## Perfect conductor

A perfect conductor or perfect electric conductor (PEC) is an idealized material exhibiting infinite electrical conductivity or, equivalently, zero resistivity (cf. perfect dielectric).

## Plasma (physics)

Plasma (Henry George Liddell, Robert Scott, A Greek English Lexicon, on Perseus) is one of the four fundamental states of matter, and was first described by chemist Irving Langmuir in the 1920s.

## Popular science

Popular science (also called pop-science or popsci) is an interpretation of science intended for a general audience.

## Power supply

A power supply is an electrical device that supplies electric power to an electrical load.

## Proportionality (mathematics)

In mathematics, two variables are proportional if there is always a constant ratio between them.

## Proton

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## Proton conductor

A proton conductor is an electrolyte, typically a solid electrolyte, in which H+ are the primary charge carriers.

## Quantum mechanics

Quantum mechanics (QM; also known as quantum physics, quantum theory, the wave mechanical model, or matrix mechanics), including quantum field theory, is a fundamental theory in physics which describes nature at the smallest scales of energy levels of atoms and subatomic particles.

## Quantum state

In quantum physics, quantum state refers to the state of an isolated quantum system.

## Quantum tunnelling

Quantum tunnelling or tunneling (see spelling differences) is the quantum mechanical phenomenon where a particle tunnels through a barrier that it classically cannot surmount.

Radio frequency (RF) refers to oscillatory change in voltage or current in a circuit, waveguide or transmission line in the range extending from around twenty thousand times per second to around three hundred billion times per second, roughly between the upper limit of audio and the lower limit of infrared.

Radio waves are a type of electromagnetic radiation with wavelengths in the electromagnetic spectrum longer than infrared light.

## Resistor

A resistor is a passive two-terminal electrical component that implements electrical resistance as a circuit element.

## Robert Andrews Millikan

Robert Andrews Millikan (March 22, 1868 – December 19, 1953) was an American experimental physicist honored with the Nobel Prize for Physics in 1923 for the measurement of the elementary electronic charge and for his work on the photoelectric effect.

## Rogowski coil

A Rogowski coil, named after Walter Rogowski, is an electrical device for measuring alternating current (AC) or high-speed current pulses.

## Schematic

A schematic, or schematic diagram, is a representation of the elements of a system using abstract, graphic symbols rather than realistic pictures.

## Semiconductor

A semiconductor material has an electrical conductivity value falling between that of a conductor – such as copper, gold etc.

## Semiconductor device

Semiconductor devices are electronic components that exploit the electronic properties of semiconductor materials, principally silicon, germanium, and gallium arsenide, as well as organic semiconductors.

## Sensor

In the broadest definition, a sensor is a device, module, or subsystem whose purpose is to detect events or changes in its environment and send the information to other electronics, frequently a computer processor.

## Shunt (electrical)

In electronics, a shunt is a device which allows electric current to pass around another point in the circuit by creating a low resistance path.

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## Siemens (unit)

The siemens (symbol: S) is the derived unit of electric conductance, electric susceptance and electric admittance in the International System of Units (SI).

## Sine wave

A sine wave or sinusoid is a mathematical curve that describes a smooth periodic oscillation.

## Single-phase electric power

In electrical engineering, single-phase electric power is the distribution of alternating current electric power using a system in which all the voltages of the supply vary in unison.

## Skin effect

Skin effect is the tendency of an alternating electric current (AC) to become distributed within a conductor such that the current density is largest near the surface of the conductor, and decreases with greater depths in the conductor.

## Sodium

Sodium is a chemical element with symbol Na (from Latin natrium) and atomic number 11.

## Solar cell

A solar cell, or photovoltaic cell, is an electrical device that converts the energy of light directly into electricity by the photovoltaic effect, which is a physical and chemical phenomenon.

## Solar wind

The solar wind is a stream of charged particles released from the upper atmosphere of the Sun, called the corona.

## Spectroscopy

Spectroscopy is the study of the interaction between matter and electromagnetic radiation.

## Speed of light

The speed of light in vacuum, commonly denoted, is a universal physical constant important in many areas of physics.

## Square (algebra)

In mathematics, a square is the result of multiplying a number by itself.

## Square wave

A square wave is a non-sinusoidal periodic waveform in which the amplitude alternates at a steady frequency between fixed minimum and maximum values, with the same duration at minimum and maximum.

## Static electricity

Static electricity is an imbalance of electric charges within or on the surface of a material.

## Temperature

Temperature is a physical quantity expressing hot and cold.

## Tensor

In mathematics, tensors are geometric objects that describe linear relations between geometric vectors, scalars, and other tensors.

## Thermal energy

Thermal energy is a term used loosely as a synonym for more rigorously-defined thermodynamic quantities such as the internal energy of a system; heat or sensible heat, which are defined as types of transfer of energy (as is work); or for the characteristic energy of a degree of freedom in a thermal system kT, where T is temperature and k is the Boltzmann constant.

## Thermionic emission

Thermionic emission is the thermally induced flow of charge carriers from a surface or over a potential-energy barrier.

## Thermocouple

A thermocouple is an electrical device consisting of two dissimilar electrical conductors forming electrical junctions at differing temperatures.

## Three-phase electric power

Three-phase electric power is a common method of alternating current electric power generation, transmission, and distribution.

## Time

Time is the indefinite continued progress of existence and events that occur in apparently irreversible succession from the past through the present to the future.

## Triangle wave

A triangle wave is a non-sinusoidal waveform named for its triangular shape.

## Two-phase electric power

Two-phase electrical power was an early 20th-century polyphase alternating current electric power distribution system.

## Vacuum

Vacuum is space devoid of matter.

## 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.

## Vacuum tube

In electronics, a vacuum tube, an electron tube, or just a tube (North America), or valve (Britain and some other regions) is a device that controls electric current between electrodes in an evacuated container.

## Valence and conduction bands

In solid-state physics, the valence band and conduction band are the bands closest to the Fermi level and thus determine the electrical conductivity of the solid.

## Velocity factor

The velocity factor (VF), also called wave propagation speed or velocity of propagation (VoP or of a transmission medium is the ratio of the speed at which a wavefront (of an electromagnetic signal, a radio signal, a light pulse in an optical fibre or a change of the electrical voltage on a copper wire) passes through the medium, to the speed of light in a vacuum.

## Volt

The volt (symbol: V) is the derived unit for electric potential, electric potential difference (voltage), and electromotive force.

## Voltage

Voltage, electric potential difference, electric pressure or electric tension (formally denoted or, but more often simply as V or U, for instance in the context of Ohm's or Kirchhoff's circuit laws) is the difference in electric potential between two points.

## Voltage source

A voltage source is a two-terminal device which can maintain a fixed voltage.

## Water

Water is a transparent, tasteless, odorless, and nearly colorless chemical substance that is the main constituent of Earth's streams, lakes, and oceans, and the fluids of most living organisms.

## Watt

The watt (symbol: W) is a unit of power.

## Waveform

A waveform is the shape and form of a signal such as a wave moving in a physical medium or an abstract representation.

## Wire

A wire is a single, usually cylindrical, flexible strand or rod of metal.

## Work function

In solid-state physics, the work setting (sometimes spelled workfunction) is the minimum thermodynamic work (i.e. energy) needed to remove an electron from a solid to a point in the vacuum immediately outside the solid surface.

## References

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