| 摘要 |
<p>PURPOSE:To realize an automatic shift to the heat insulation state, by combining a timer and a heat-sensitive resistance element and then lowering the sensing temperature of the heat-sensitive resistance element after a prescribed set time. CONSTITUTION:The temperature of the cooking pot heated by the heater 3 is detected by the bridge circuit 18 using the heat-sensitive resistance element 23 for one side. When the temperature reaches the set level, the timer 9 is started by the output of the transistor TR17. At the same time, the thyristor 15 is controlled via the gate circuit 16 to keep the temperature of the heater 3 at a constant level. Then a resistance is connected in parallel to the element 23 when the timer set time elapses, and thus the sensing temperature lowers to be controlled thereafter by the heat insulating temperature. The switches 11 and 33 are provided to vary the resistance value of the circuit 18 to set the heat insulating temperature at a constant level for a high- and low-temperature cooking. In such way, an automatic shift is secured to the heat insulation state.</p> |
