What happens to the magnitude of eddy currents and skin effect when circuit frequency increases?

When the frequency of a circuit increases, both the magnitude of eddy currents and the skin effect tend to increase.

Eddy currents are loops of electric current induced within conductors by a changing magnetic field, and their magnitude is directly linked to the rate of change of the magnetic field. As the frequency increases, the rate of change becomes faster, leading to a greater induced current. This occurs because higher frequencies enhance the alternation of the electromagnetic fields, promoting larger eddy current formation as they have less time to dissipate before the magnetic field changes direction.

Similarly, the skin effect describes the phenomenon where alternating current (AC) tends to flow primarily near the surface of a conductor rather than uniformly throughout its volume. As frequency increases, the skin depth, which determines how deeply the current can penetrate into the conductor, decreases. This results in a concentration of current at the surface, effectively increasing the overall current density in that surface layer.

Therefore, both eddy currents and skin effect exhibit an increase in magnitude with higher frequencies. This phenomenon is critical for understanding losses in AC circuits and the behavior of conductors in high-frequency applications.