Abstract: A matrix transformer includes a magnetic core structure and windings. The magnetic core structure includes magnetic legs and a pair of spaced-apart magnetic plates that are connected together by the magnetic legs. The windings are wrapped around the magnetic legs and have electric current flow directions which cause magnetic fluxes within the magnetic core structure that cancel out in a middle region of each magnetic plate thereby leaving the middle region of each magnetic plate to be a magnetic field-free zone. A first one of the magnetic plates has a recess extending through its middle region within its magnetic field-free zone. A cooling pin connected to a heat sink is insertable through the recess.

Abstract: A method for controlling an electrical load by means of pulse width modulation, (PWM) includes specifying a setpoint switching frequency fsetpoint and a setpoint duty ratio dsetpoint and determining the carrier frequency fch of a radio transmitter. The actual switching frequency fsw of the PWM is adapted to the carrier frequency fch of the radio transmitter in such a way that a multiple k*fsw of the actual switching frequency fsw is equal to the carrier frequency fch with an integer factor k. The actual switching frequency fsw is set to the value closest to the setpoint switching frequency fsetpoint for which the amplitude of the harmonics k*fsw in the harmonic spectrum of the actual switching frequency fsw is smaller than the amplitudes of their closest lower (k?1)*fsw and upper (k+1)*fsw adjacent harmonics.

Abstract: A method for controlling an electrical load by means of pulse width modulation, (PWM) includes specifying a setpoint switching frequency fsetpoint and a setpoint duty ratio dsetpoint and determining the carrier frequency fch of a radio transmitter. The actual switching frequency fsw of the PWM is adapted to the carrier frequency fch of the radio transmitter in such a way that a multiple k*fsw of the actual switching frequency fsw is equal to the carrier frequency fch with an integer factor k. The actual switching frequency fsw is set to the value closest to the setpoint switching frequency fsetpoint for which the amplitude of the harmonics k*fsw in the harmonic spectrum of the actual switching frequency fsw is smaller than the amplitudes of their closest lower (k?1)*fsw and upper (k+1)*fsw adjacent harmonics.