Abstract: A choke coil apparatus for an electromagnetic range comprises an improved ferrite core, so as to prevent an increasing in temperature of the choke coil. The ferrite core in a multiangular bar-shape forms a plurality of ventilation spaces between the choke coil and the ferrite core, thereby air-cooling the choke coil by the air flowing in the ventilation space.

Abstract: This invention relates to an unnecessary electromagnetic wave shielding structure of a magnetron for a microwave oven, comprising an electric wave absorbent filament ceramic disposed adjacent the lower end of a power input section to prevent unnecessary electromagnetic waves produced in an active space from being leaked from the input section through a center lead extending downwardly from an upper end shield of the active space and a side lead disposed adjacent the center lead; first and second ferrite cores having different frequency characteristics and inserted concentrically over the filament ceramics at the respective upper and lower sides of the outer periphery thereof to cooperate with the ceramics to shield the unnecessary electromagnetic waves; and an annular insulator placed between the second ferrite core and filament terminals to insulate the ferrite core from the terminals.

Abstract: In a magnetron for a microwave oven comprising a plurality of vanes as an anode and an antenna feeder mounted to the vanes, an antenna feeder fixing device comprising a plurality of radially spaced grooves formed at the upper surface of every other vane so that the antenna feeder is engaged with one of the grooves selected depending on the output of the magnetron. The antenna feeder fixing device can be applied to various models of magnetrons having different outputs, without changing the construction of vanes. This enables modular elements to be used for providing various models of magnetrons, irrespective of different outputs of magnetrons. Only one mold is needed for preparing a single vane construction having a plurality of grooves for various magnetron models, thereby enabling the manufacture cost to decrease.