| 摘要 |
A microwave oven circuit includes a magnetron power transformer and a duty cycle controlled switching element connected to periodically energize the power transformer from an AC power source. Due to the effects of power source loading, the available AC voltage drops during those intervals when the power transformer is energized. This undesirably causes cyclical variation in the operation of certain constantly energized load devices such as the oven lamp and the motor for the blower which provides cooling air for the magnetron. To minimize the undesirable voltage variation, a low voltage secondary winding on the magnetron power transformer is connected in series with the constantly energized load device and properly phased to provide a voltage boost upon energization of the power transformer. Preferably, the low voltage secondary winding is an otherwise unused winding originally intended to be a magnetron filament winding. As a result, very little additional cost is involved.
|
