Types and working principles of thermistors

　　(1) Type of thermistor. Thermistors can be divided into positive temperature coefficient thermistors (PTCR) and negative temperature coefficient thermistors (NTCR) according to their resistance-temperature characteristics. PTC is the abbreviation of Positive Temperature Coefficient, which means positive temperature coefficient. NTC is the abbreviation of Negative Temperature Coefficient, which means negative temperature coefficient.

　　The positive temperature coefficient thermistor is also divided into abrupt type (also called step type) and slowly changing type (linear). The mutant type is subdivided into two categories: one is ceramic PTC thermistor (CPTC), and the other is organic polymer PTC thermistor (PPTC).

　　(2) Interpretation of the main parameters of the PTC thermistor. Table 2-25 shows the interpretation of the main parameters of the PTC thermistor.

　　The resistance-temperature characteristic curve is the relationship between the zero-power resistance value of the PTC thermistor and the temperature of the resistor body under a specified voltage. The voltage-current characteristic curve is the relationship between the voltage applied to the terminal of the thermistor and the current under steady-state conditions to achieve thermal equilibrium. The current-time characteristic curve is the change characteristic of current with time in the process of applying voltage to the thermistor. The current at the moment when the voltage is applied is called the initial current, and the current at equilibrium is called the residual current.

　　(4) As shown in Figure 2-26 is the resistance-temperature characteristic curve of the negative temperature coefficient (NTC) thermistor. It can be seen from the curve that the resistance decreases as the temperature increases.

Read recommendations:

NTC temperature sensor for fruit tree seedling cultivation and irrigation equipment

NTC temperature sensor for insulation cup

PIR Lens 8310

PIR Lens 7709-2

TP-L80