electric current density

physics

Also known as: current density

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June 24, 2026

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Current density refers to the amount of electric current flowing through a specific cross-sectional area. It is measured in amperes per square meter and is symbolized by J. This concept is crucial in understanding how electricity flows through conductors.12

In a wire, current density is directly related to the electric field and the material's conductivity, as described by Ohm's law: J = \u03c3_JE, where \u03c3_J is the conductivity and E is the electric field. A higher current density means more charge is passing through a given area per unit of time. This can lead to increased heat generation within the conductor.23

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electromagnetism
Effects of varying electric fields
…the total flux of the current density J through any surface surrounded by the closed path. In Figure 6A, the closed path is labeled P, and a surface S₁ is surrounded by path P. All the current density through S₁ lies within the conducting wire. The total flux of the…
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…the total flux of the current density J through any surface surrounded by the closed path. In Figure 6A, the closed path is labeled P, and a surface S₁ is surrounded by path P. All the current density through S₁ lies within the conducting wire. The total flux of the…
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electricity
Basic phenomena and principles
…the flow of charge is current density, the flow of current per unit area. Symbolized by J, it has a magnitude of i/A and is measured in amperes per square metre.
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…the flow of charge is current density, the flow of current per unit area. Symbolized by J, it has a magnitude of i/A and is measured in amperes per square metre.
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electrochemical reaction
Mechanism of charge transfer
…best be described as the electric current density—i.e., a measure of the quantity of electrons moving in a certain volume of space during a specified unit of time.
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…best be described as the electric current density—i.e., a measure of the quantity of electrons moving in a certain volume of space during a specified unit of time.
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electron tube
Thermionic emission
The former states that the current per unit of area, J, is given by where k is Boltzman’s constant, A is a constant of the material and its surface finish and is theoretically about 120 amperes per square centimetre per kelvin, T is the temperature of the solid, and W…
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The former states that the current per unit of area, J, is given by where k is Boltzman’s constant, A is a constant of the material and its surface finish and is theoretically about 120 amperes per square centimetre per kelvin, T is the temperature of the solid, and W…
Read More