| 摘要 |
PURPOSE:To prevent a means for switching from chattering at the stopping of the operation of a means for generating heating energy when the temperature of foodstuff is higher than the set temperature by a method wherein the circuit configurations concerning a temperature detection comparator and latch comparator are changed. CONSTITUTION:The operation of a thermal treatment unit 11 in a microwave cooker is as follows: Firstly, a voltage corresponding to the set temperature set by a variable resistor VR and a voltage corresponding to the temperature of foodstuff given by a thermistor 10 are compared with each other by a first comparator 15. Secondary, a switching transistor Tr 16 is kept on turning on until said two voltages become equal to each other by exciting a relay coil 17 so as to turn a relay switch 7 to close a NO contact side in order to put the means for generating heating energy 5 into operation. At this time, resistors R10 and R11 are connected between a power source line 20 and a resultant output of the first comparator 15 directly connected with the second comparator 23, which is provided for inhibiting the reheating after the stop of microwave oscillation, so as to apply the voltage divided by the resistors R10 and R11 to the plus input terminal of the comparator 23. On the other hand, the minus terminal of the comparator 23 is connected to a line 22 and to a power source line 21 through a capacitor C2. |
