In an electrical or electronic circuit or power system part of the energy in play is dissipated by unwanted effects, including energy lost by unwanted heating of resistive components, the effect of parasitic elements, skin effect, losses in the windings and cores of transformers due to resistive heating and magnetic losses caused by eddy currents, hysteresis, unwanted radiation, dielectric loss, corona discharge, and other effects. There are also losses during electric power transmission.