Alternating fields are in strength and polarity changing electric or magnetic fields caused by the AC voltage or current are caused.
Alternating electrical fields arise between conductors or (in the case of capacitors ) circuit boards with different potentials . If the insulation consists of certain substances whose molecules are polarized, these change their position in the rhythm of the applied frequency , which leads to heating and energy losses , especially at very high frequencies .
Alternating magnetic fields are generated by coils and conductors ( inductors ) through which alternating current flows. The magnetic field follows the level and direction of the applied voltage with a time delay ( phase shift ). Coils can be equipped with magnetically conductive (e.g. iron or ferrite ) cores, which reinforce the fields, but at the same time increase the inductance. Since alternating fields cause eddy currents in massive iron cores , which result in energy losses and heating, cores for alternating current applications are made of layered, electrically insulated sheet metal.
- Horst Stöcker: Pocket book of physics. 4th edition, Verlag Harry Deutsch, Frankfurt am Main, 2000, ISBN 3-8171-1628-4