Back

Skin effect: AC field in a conductor

What you are seeing: the electric field E(z,t)=E0e−z/δcos⁡(ωt−z/δ)E(z, t) = E_0 e^{-z/\delta} \cos(\omega t - z/\delta) inside a conductor. The skin depth δ=2/(ωμσ)\delta = \sqrt{2/(\omega \mu \sigma)} shrinks with frequency. Cu at 60 Hz: 8.5 mm; at 1 GHz: 2 μm.

Figure 1. Penetration of an AC E-field into a conductor; envelope is e−z/δe^{-z/\delta}.
log10(f) Hz1e6
material

WHAT TO TRY

  • Vary each control and watch the rail readouts respond.
  • Compare the diagnostic plot against the live scene.