ihonvaikutuksen

Ihonvaikutuksen is a Finnish term that translates to "skin effect" in English. It refers to a physical phenomenon where an alternating electric current tends to distribute itself within a conductor such that the current density is greater at the surface of the conductor than in the interior. This effect becomes more pronounced as the frequency of the alternating current increases.

The skin effect is caused by the magnetic field that is generated by the alternating current itself. As the current changes direction, it induces eddy currents within the conductor. These eddy currents oppose the original current, and their effect is strongest in the center of the conductor, pushing the main current towards the outer surface.

The depth to which the current penetrates into the conductor is known as the skin depth. This depth is inversely proportional to the square root of the frequency of the current, the conductivity of the material, and the permeability of the material. Consequently, at high frequencies, the current flows only in a very thin layer near the surface.

This phenomenon has important implications in electrical engineering. For example, it affects the resistance of conductors at high frequencies. To mitigate the skin effect, conductors used in high-frequency applications are often made of hollow tubes or are composed of multiple thin strands of wire insulated from each other (Litz wire). The skin effect is also a factor in the design of transformers and inductors.