Physical world and mathematics

Electric Power Research Institute

The Electric Power Research Institute is an independent nonprofit that conducts energy and environmental research for the electricity sector, founded in 1972 and headquartered in Palo Alto, California.

Electric spark

An electric spark is a sudden, transient electrical breakdown of a gas gap between electrodes, in which the gas ionizes into a luminous plasma channel carrying a burst of current.

Electric susceptibility (χe)

Electric susceptibility (χe) is a dimensionless constant measuring how strongly a dielectric material polarizes in response to an applied electric field, related to permittivity by εr = 1 + χe.

Electric-field-induced second harmonic generation spectroscopy

Electric-field-induced second harmonic generation spectroscopy (EFISHG) is a nonlinear optical technique that uses a static electric field to induce second harmonic generation in centrosymmetric materials.

Electric-field-induced superconductivity

Electric-field-induced superconductivity is the creation of superconductivity in a non-superconducting material using a gate electrode, pioneered in ZrNCl and extended in 2012 to MoS2, which turned superconducting near 9.4 K.

Electrical breakdown

Electrical breakdown, also called dielectric breakdown, is the abrupt loss of insulating behavior when the applied electric field exceeds a critical value and a conducting path forms.

Electrical capacitance tomography

Electrical capacitance tomography (ECT), also called capacitance tomography, is a non-invasive imaging method that reconstructs permittivity inside pipes and vessels from capacitance measurements between external electrodes, used to monitor multiphase flows and fluidized beds.

Electrical conductivity measurement

Electrical conductivity measurement is an experimental characterization method that determines how well a material conducts electric current, serving semiconductor wafer, battery, thin-film, and water-purity applications.

Electrical conductivity meter

An electrical conductivity meter, also called an EC meter, is an instrument that measures the conductivity of a liquid, reporting it in siemens per centimeter.

Electrical conductor

An electrical conductor, or conductor of electricity, is a material with mobile charged particles, such as a metal's free electrons, that lets charge flow under an applied voltage.

Electrical energy

Electrical energy is the energy associated with electric charges and their electric fields, delivered as work when charges move through a potential difference, and measured in joules.

Electrical impedance

Electrical impedance is the opposition a circuit presents to alternating current, combining resistance and reactance into one complex quantity, symbol Z, in ohms, generalizing DC resistance.

Electrical load

An electrical load, also called an external load, is any circuit component that consumes electrical power, converting it into light, heat, or motion; appliances and motors are common examples.

Electrical mobility

Electrical mobility, also called carrier mobility, is a measure of how readily electrons or holes move through a material under an applied electric field, in cm²/(V·s).

Electrical polarity

Electrical polarity is the designation of the two terminals or poles of an electrical source or device as positive and negative, and their relationship in a circuit.

Electrical reactance

Electrical reactance, denoted X, is the opposition a capacitor or inductor presents to alternating current, measured in ohms; unlike resistance, it stores energy rather than dissipating it and depends on frequency.

Electrical resistance and conductance

Electrical resistance is a circuit element's opposition to electric current, R = V/I, measured in ohms; conductance, its reciprocal, measures how easily current flows, in siemens.

Electrical resistivity and conductivity

Electrical resistivity, or specific electrical resistance, is an intrinsic material property measuring how strongly it opposes electric current, measured in ohm-meters; conductivity, its reciprocal, measures how well the material conducts.

Electrical resistivity imaging

Electrical resistivity imaging, also called electrical resistivity tomography (ERT), is a geophysical method that maps subsurface resistivity by injecting current and measuring voltage, used to find groundwater, contaminants, and geology.

Electrical resistivity method

The electrical resistivity method is a geophysical surveying technique, originating in the 1910s, that injects current into the ground to map groundwater, salinity, fractures, and contaminants.

Electrical resistivity tomography

Electrical resistivity tomography (ERT) is a geophysical imaging method that reconstructs subsurface electrical resistivity from electrode measurements, producing 2D sections and 3D volumes for hydrogeology, geotechnics, and environmental studies.

Electrical switching of antiferromagnetic order

Electrical switching of antiferromagnetic order is the use of electric current or voltage pulses to reverse the magnetic order of an antiferromagnet, demonstrated experimentally from 2016.

Electrical switching of antiferromagnetism in CuMnAs

Electrical switching of antiferromagnetism in CuMnAs is the reorientation of CuMnAs's antiferromagnetic order by current pulses, first demonstrated at room temperature by Wadley and colleagues in 2016.

Electrical switching of antiferromagnets

Electrical switching of antiferromagnets is the use of electric current or voltage, rather than magnetic fields, to reverse the Néel vector of antiferromagnets, demonstrated since 2016 in materials such as CuMnAs.

Electrical termination

Electrical termination is the practice of ending a transmission line with a load whose impedance matches the line, absorbing signal energy instead of reflecting it.

Electrically driven single-photon emitters in 2D semiconductors

Electrically driven single-photon emitters in 2D semiconductors are devices in which atomically thin WSe₂ emits one photon at a time in response to injected electrical charge rather than laser excitation.

Electricity

Electricity is the set of physical phenomena associated with electric charge, the property of matter that makes objects attract or repel, including currents, fields, and static charge.

Electride

An electride is an ionic crystal in which electrons unbound to any nucleus act as the anions, first synthesized in 1983 and valued in catalysis and electronics.

Electro-absorption modulator

An electro-absorption modulator (EAM) is a semiconductor device that controls light transmission by applying an electric field, enabling bandwidths above 50 GHz at low drive voltages.