Displacement Current
A fictitious effective current term introduced by Maxwell to account for magnetic field generation by time-varying electric fields.
Governing formula
I_d = ε₀ (dΦ_E / dt)
SI unit
A (Amperes)
In depth
Displacement current completes Ampere's law for non-steady circuits (such as charging capacitors), ensuring charge conservation and predicting self-sustaining electromagnetic wave propagation in vacuum.
Examples in the real world
The effective displacement current passing through the dielectric gap between charging capacitor plates that generates a surrounding magnetic field.