Negative temperature coefficient (NTC) thermistor has many advantages, such as sensitivity to temperature changes, short response time, low price, wide temperature measurement range and good interchangeability. It has been widely used in many fields such as temperature measurement and control, voltage stabilization, compensation, surge current suppression, and flow rate measurement. Especially with the continuous development of modern emerging industries and the continuous improvement of the quality of new products. The application range of NTC thermistor is also expanding, and it is widely used in people's daily life and work.

The ceramic chip encapsulated inside the NTC thermistor is the core of this type of electronic components. This type of NTC thermal ceramics is generally made of metal oxide oxide powders of several 3d transition metals such as Mn, Ni, Co, Fe, Cu and Zn as raw materials, using semiconductor ceramic preparation technology. A class of inorganic functional materials with spinel structure as the main crystalline phase formed by sintering at high temperature. The behavior of NTC thermistor's resistance despite temperature change is generally described by the Arrhenius formula: ρ=ρ0exp(Ea/kT). In actual use, two basic electrical parameters are generally used to represent the electrical parameters of NTC thermistors:
(1) ρ25°C, which is the resistivity at 25°C;
(2) The value of B is defined as B=Ea/k, which represents the degree of resistance change with temperature.
In the actual use of NTC thermistors, manufacturers are usually required to provide resistance and B-value products with different parameters. This requires the adjustment and design of the ceramic chip formulation, so material systems with different compositions have been developed. Common material systems include Ni-Mn-O, Cu-Mn-O, Co-Mn-O binary systems and ternary or even multi-element systems composed of other elements added on this basis. These material systems can form a ceramic sintered body with a spinel structure as the main crystal phase within a certain composition range and temperature. And the resistance value and the thermal constant B value can be adjusted within a certain range. These rich material systems provide sufficient and diverse formula design guarantees for the actual production of different types of NTC thermistors in the industry.