A power supply comprises at least one input to couple the power supply to a power source. The power supply also comprises at least one switched-mode power circuit configured to extract electrical energy from the power source, the electrical energy to be transferred to a load. The power supply additionally comprises at least one control module coupled between the at least one input and the at least one switched-mode power circuit. The control module is configured to control operation of the switched-mode power circuit to regulate a voltage-to-current ratio at the at least one input of the power supply.

A high frequency high power converter system comprises: a plurality of resonant tank circuits arranged in parallel, a plurality of transformers, each transformer having a single primary winding and a plurality of secondary windings, and a vacuum electronic device, the output of each resonant tank circuit being applied to a respective different transformer and the outputs of the transformers being arranged to drive the vacuum electronic device.

A power supply for a magnetron has a high voltage converter, a microprocessor and a resistor. The high voltage converter comprises an integrated circuit oscillator, switching transistors, an inductance L1, a transformer and a rectifier. A voltage source supplies an augmented DC voltage to the converter. An operational amplifier, arranged as an error signal magnifier with an integrating capacitor and a resistor, compares a control signal from the microprocessor and the resistor and supplies an output signal to the oscillator. The oscillator controls the switching transistors, the output of which is connected to the inductance and the primary winding of the transformer. The secondary winding of the transformer is connected to half bridge diodes and capacitors, which provide DC current from the transformer to the magnetron.

A radio frequency heating apparatus includes a printed circuit board on which power-supply noise filter circuit (20) that reduces power-supply noise generated by magnetron (15) and power-supply synchronization detecting circuit (21) that is connected across both terminals of power supply for detecting information on power-supply frequency are mounted. Power-supply synchronization detecting circuit (21) is used as a discharge path for charge accumulated at both ends of capacitor (3) configuring power-supply noise filter circuit (20). This achieves the radio frequency heating apparatus that eliminates the risk of electric shock, reduces power consumption, and reduces the number of components.