ABSTRACT
According to the physical quantity sensitive to temperature the ceramic temperature sensors are: resistive, capacitive, and inductive. In accordance with the functional dependence of the resistance on temperature the resistive temperature sensors are: NTC-thermistors, PTC-thermistors and CTR-thermistors. The current-voltage relationship of the NTC-thermistors must be in the form of a straight line, but the real static characteristics are nonlinear. The materials for NTC-thermistors may be classified according to different principles such as: chemical composition, temperature range, etc. As regards their composition the thermistors are made from spinels, solid electrolytes and other materials. Pure oxide solid electrolytes are not used because they have high resistance and their ionic conductivity is revealed at very high temperatures. According to the operating principle PTC-thermistors are classified three ways: on the basis of ferroelectric-to-paraelectric phase transition in the semiconducting ceramics, on the basis of metal-to-insulator phase transition, and on the basis of polymer-based composites.
