JPS5530683A - Multi-point temperature detector - Google Patents

Abstract

PURPOSE: To reduce the number of the temperature detecting output terminals and to improve the measuring accuracy by consecutively switching the preset resistances of a resistor bridge which is equipped with a heat-sensitive element at its one side.

CONSTITUTION: The outside information from an input device 3 and the output from a temperature detecting circuit 4 are fed to a CPU 1, by which the time information is fed to a display circuit 2 whereas the load control information is fed to a control circuit 5 so that this circuit 5 controls the load of an exothermic element. The temperature detecting circuit 4 is equipped with a resistor bridge 18, which is composed of resistors 6, 7, 10, 11, 15 and 9 and a thermister 8. A comparator 17 is inverted, when the level at the connection between itself and a resistor parallel circuit becomes higher than the level at the connection between the resistors 6 and 7, thereby to generate the temperature detection output. The respective transistors of a switching circuit 22 for switching the resistances of the bridge are consecutively energized by the output of a digit drive circuit 19 of the detector 1 so that the output signals of the comparator 17 take the values of the four points having different temperature levels and are stored in the detector 1 at 21.

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