Comparison of displacement current with conduction current

Comparison of Displacement Current and Conduction Current

Conduction Current

Conduction current is the flow of electric charge through a conductor, such as a wire. It is typically associated with the movement of electrons in a metal conductor.

Mathematically, conduction current (I_c) is given by Ohm's law:

I_c = σA E

Where:
I_c is the conduction current,
σ is the conductivity of the material,
A is the cross-sectional area of the conductor,
E is the electric field.

Displacement Current

Displacement current is associated with the changing electric field in a region of space. It was introduced by James Clerk Maxwell to modify Ampère's law to be consistent with the continuity equation.

Mathematically, displacement current (I_d) is given by Maxwell's addition to Ampère's law:

I_d = ε₀ A (dE/dt)

Where:
I_d is the displacement current,
ε₀ is the permittivity of free space,
A is the cross-sectional area of the region,
(dE/dt) is the rate of change of electric field with respect to time.

Comparison

The key difference between conduction current and displacement current is that conduction current is associated with the actual flow of charge in a conductor, while displacement current is associated with the changing electric field in a region of space.

Both types of currents play a crucial role in the complete expression of Maxwell's equations and the understanding of electromagnetism.