| 摘要 |
PURPOSE:To prevent burnt damage on a high voltage rectifier and so on by providing an anodic current detector between a rectifying circuit on the secondary side of a temperature rising transformer and the anode of a magnetron, and by stopping the operation of the magnetron when the detected current value becomes smaller than an allowable minimum current value. CONSTITUTION:The output signal of a current smoothing circuit 25 is input into a deviated current amplifier 26 as well as a minimum current comparator circuit 31. An average anodic current value Iav output from the circuit 25 is compared with a fixed allowable minimum current value Io, by the circuit 31, and when the average anode current value Iav becomes smaller than the allowable minimum current value Io, a high level abnormality detection signal S5 is output to an abnormality judgment circuit 32. When the output time of the abnormality detection signal S5 becomes longer than a predetermined level, a stop signal S6 of low level is output to an AND gate 28 so as to make non- conductive, by the abnormality judgment circuit 32, while the stop signal S6 is output to a display device 33 which is an alarm device provided on a front surface operation panel, and the message showing abnormality generation is displayed on the display device 33.
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