Negative temperature coefficient thermal resistor with variable thermosensitive index

Abstract

The invention discloses a negative temperature coefficient thermal resistor with a variable thermosensitive index, comprising a thermal resistor chip which is obtained by the following steps of: lamination and roasting of blank films and extruded formation of rolling films, wherein the blank films are obtained by slurry casting and drying formation of transition metal oxide mixed powders. The negative temperature coefficient thermal resistor with the variable thermosensitive index is characterized in that the blank films include high-B value blank films and low-B value blank films; the high-B value blank film contains 40-60mol% of manganese oxide MnO2, 30-50mol% of cobalt oxide Co3O4 and 1-20mol% of ferric oxide Fe2O3; and the low-B value blank film contains 40-60mol% of manganese oxide MnO2, 1-30mol% of nickel oxide Ni2O3 and 1-20mol% of ferric oxide Fe2O3. The value B rises as the temperature increases, thus the thermal resistor has a positive B-T characteristic, and the negative temperature coefficient alpha is within the temperature range from -100 DEG C to 150 DEG C, and the temperature coefficient is stably maintained within the range from -4% to -2%.

Description

technical field [0001] The invention relates to a thermistor, in particular to a negative temperature coefficient thermistor with variable thermal index. Background technique [0002] The thermal index B of an existing negative temperature coefficient (Negative Temperature Coefficient, abbreviated as NTC) thermistor is a fixed constant, also known as a material constant. There is only one B value for each formulation and sintering temperature, and the higher the resistivity, the larger the B value. In addition, the B value is positively correlated with the temperature coefficient (Temperature Coefficient, abbreviated as TC) α of the NTC thermistor, and the relationship is α=-B / T 2 , that is to say, the larger the B value, the larger the α value. In the low temperature area, a low B value thermistor with a B value < 1500 is generally used for measurement, and in the high temperature area, a high B value thermistor with a B value > 5000 is generally used. Resistance is...

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Problems solved by technology

When using an NTC thermistor to measure a wide range of temperatures from -100 to 100°C, choose a low B value thermistor with a B value of 1000 for measurement, and its temperature coefficient α is too large, which is -3 to -0.6%; Choose a thermistor with a high B value of 4500 for measurement, and its temperature coefficient α is too small, which is -15 to -3%, making it difficult to control the measurement accuracy. It is necessary to keep the temperature coefficient α of the NTC thermistor at Variable range of thermal index

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