Positive temperature coefficient heating element temperature control method

Abstract

The invention relates to a temperature control method for a positive temperature coefficient heating element which has deviation resistance value; the method adopts a circuit which at least includes a resistive component RT7, a resistor RB 10 and a resistor RA9 to measure the temperature of a temperature measuring point VT17 and to carry out control at a stated temperature. When the resistive component is used as a thermometric component, due to the problem of manufacturing, the resistive thermometric component has relatively large deviation; therefore, the accuracy of temperature can be affected. The technical proposal of the invention is that the burning process of the resistor RB and the resistor RA is set in advance, the temperature of a temperature control point is continuously compared with the actual temperature in a temperature measuring program, as the selection of resistance values of the resistor RB and the resistor RA eliminates the deviation of resistance values, the components of the category can also be conveniently applied to the situation of temperature control, thus solving the difficult problem of screening components in the past, lowering the technical requirements for manufacturing components and expanding the application scope of the component in the category.

Description

technical field [0001] The invention relates to a temperature control method of a positive temperature coefficient heating element, in particular to a temperature control method in which the resistance value of the positive temperature coefficient heating element deviates. Background technique [0002] Heating elements with a positive temperature coefficient are heating elements made of alloy materials, such as cermet heating elements, metal heating wires, and the like. Since the positive temperature coefficient heating element has a positive temperature coefficient characteristic, its resistance value will continue to increase with the increase of temperature, so the heating element can also be used as a temperature measuring element of a constant temperature control circuit. [0003] Generally, in the manufacturing process of positive temperature coefficient heating elements, the temperature coefficient k is determined by the material ratio (the percentage of various mater...

AI Technical Summary

Problems solved by technology

The traditional linear temperature control method has very high requirements for the consistency of the resistance value of the positive temperature coefficient heating element at a certain temperature, generally within ±1%, so when used as a temperature measuring element of a constant temperature control circuit, it needs to pass the screening , resulting in higher processing costs, if the requirements for heating applications can be reduced, the processing costs can be reduced

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