Patent ID: 7414228

Claim:
A high frequency heating apparatus comprising: a unidirectional power source portion for converting a commercial power source in a unidirection; at least one piece of a semiconductor switching element; an inverter portion for converting a power from the unidirectional power source portion into a high frequency power by making the semiconductor switching element to ON/OFF; a boost transformer for boosting an output voltage of the inverter portion; a high voltage rectifying portion for subjecting an output voltage of the boost transformer to multiplying voltage rectification; a magnetron for irradiating an output of the high voltage rectifying portion as an electromagnetic wave; a shunt resistor electrically interposed in series with a portion capable of measuring an output current of the unidirectional power source portion and arranged along a wind path of a cooling wind flowing above the board; a buffer for outputting a voltage generated by making a current flow to the shunt resistor; and a control portion for controlling ON/OFF of the semiconductor switching element to control constant an output of the buffer to a predetermined value.