Patent ID: 6621226
Filing Date: 2003-09-16
Classification: H05B

Abstract:
A method for controlling voltage in a microwave oven which includes a magnetron, said method comprising:providing a high voltage transformer which includes a secondary coil which has a first coil part and a second coil part; supplying a voltage from an external source to the high voltage transformer so as to induce a low voltage in the first coil part and a high voltage in the second coil part; applying the high voltage from the second coil part as an anode peak voltage between an anode and a cathode of the magnetron, thereby commencing an early non-oscillating period of the magnetron; supplying the low voltage from the first coil part to a filament of the magnetron so as to provide a stabilized voltage to heat the filament during the early non-oscillating period of the magnetron; lowering the anode peak voltage to a first level during the early non-oscillating period of the magnetron; terminating the early non-oscillating period of the magnetron once the filament is heated to a certain degree; and lowering the anode peak voltage to a second level, lower than the first level, when the early non-oscillating period of the magnetron is terminated.