Skin Effect

Definition: This is the effect of AC current mainly flows along the outer surface of a conductor.

Skin depth is used to characterized level of skin effect within a conductor. It's defined as the depth in which the current density is 37% of current found on the conductor surface.

Impact:

• AC resistance of the conductor increases as frequency increases
• Skin depth of conductor decreases as frequency increases
  • Note: reduced skin depth effectively reduces cross-sectional area of conductor and increases its resistance to current flow.

Reference and Further Reading:

"Skin Effect", https://en.wikipedia.org/wiki/Skin_effect