What is the material constant of the thermistor?

The role of the thermistor is believed to be understood by everyone. So, do you know the definition and meaning of the material constant of the thermistor? For the material constant, what it can achieve is to ensure that the sensitivity of the entire electronic component is guaranteed.

The material constant of the thermistor, that is, the thermistor chip (a kind of semiconducting ceramic), after being sintered at a high temperature, forms a material having a certain resistivity, and each formulation and sintering temperature has only one B value, so the material is a material. constant. The B value can be calculated by measuring the resistance values at 25 degrees Celsius and 50 degrees Celsius (or 85 degrees Celsius). The B value is positively correlated with the product temperature coefficient of resistance, that is, the larger the B value, the larger the temperature coefficient of resistance.

The temperature coefficient refers to the rate of change of the resistance value for every 1 degree increase in temperature. The B value can be converted into the temperature coefficient of resistance by the following formula: temperature coefficient of resistance = B value / T^2 (T is the point temperature value to be converted). The B value of the NTC thermistor is generally between 2000K and 6000K. It cannot be said simply that the larger the B value, the better or the smaller, the better. It depends on where it is used. In general, as a product for temperature measurement, temperature compensation, and suppression of surge resistance, the B value is better under the same conditions. Because the product with a large B value changes its resistance value more with the change of temperature, that is to say, it is more sensitive.

Thermistors are semiconductor devices fabricated using the temperature-dependent characteristics of the resistivity of semiconductor materials. The thermistor time constant τ is a parameter describing the thermal inertia of the thermistor. It is defined as the time required for the temperature change of the thermistor to reach 63% of the difference between the temperature of the thermistor and the ambient temperature. The time constants of the thermistors vary widely.

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