Power control

The present invention relates to a method and an apparatus for controlling the power supplied to an electric apparatus. The invention comprises a voltage switch adapted to connect or disconnect a voltage applied to said electric apparatus, and, if the applied voltage in average is higher than a nominal voltage during at least a first portion of a period, to disconnect said applied voltage during at least a second portion of said period, whereby the total energy supplied to said apparatus during said period will be equal to a first specified energy.