HIGH-FREQUENCY HEATING DEVICE EMPLOYING SWITCHING TYPE MAGNETRON POWER SOURCE

摘要

A high-frequency heating device (microwave oven) comprises a power converter for converting electric power from a commercial source into high-frequency power. A step-up transformer has a high-voltage winding and a low-voltage winding. A magnetron receives the high-voltage and lowvoltage outputs. A resonance circuit is connected in series or in parallel with the filament of the magnetron. A control circuit controls the power converter such that the operating frequency of the power converter approximately coincides with the resonance frequency of the resonance circuit at the time of activating the power converter. The advantage is to achieve a rapid start of oscillation of the magnetron, while suppressing the high voltage that previously occurred at activation to avoid occurrence of the moding phenomenon.