| 摘要 |
<p>72372-1 Of Invention A heat variation detecting circuit, for use with a heat sensor in a microwave oven, comprising a heat sensor, temperature memorizing registers, comparators for controls. The heat temperature sensed in a heat sensor is converted via an A/D converter into a digital signal and stored in a present temperature register. This value is compared with the value stored in a prior temperature register and, if the value is the same, an error counter is stopped. The content of the prior temperature register is continuously updated from the present temperature register via a buffer register and the contents of the two registers continuously compared. As long as the values remain the same the error counter continues to count. When the error count reaches a predetermined value in a presetting register, this indicates a fault in the sensing circuitry and the oven is switched off and an alarm signal sent. FA-86-0010</p> |
