The definition and material of the thermistor

1. Thermistor definition

The thermistor is a component with high sensitivity and is divided into a positive temperature coefficient thermistor (PTC) and a negative temperature coefficient thermistor (NTC) according to the temperature coefficient. Typical characteristics of thermistors are their sensitivity to temperature and different resistance values at different temperatures. The positive temperature coefficient thermistor (PTC) has a higher resistance value at higher temperatures, and the lower the resistance value of the negative temperature coefficient thermistor (NTC) at higher temperatures, they belong to the semiconductor device.

The thermistor will be in a non-operating state for a long time; when the ambient temperature and current are in the c-zone, the heat-dissipating power of the thermistor is close to the heating power, and thus the thermistor may not operate. When the thermistor has the same ambient temperature, the operating time is sharply shortened as the current increases. The thermistor has a shorter operating time and a smaller holding current and operating current when the ambient temperature is relatively high.

2. The material of the thermistor

The ptc effect is a material with a PTC (positive temperature coefficient) effect, that is, a positive temperature coefficient effect, which only means that the resistance of the material increases with increasing temperature. For example, most metal materials have a ptc effect. Among these materials, the ptc effect appears as a linear increase in electrical resistance with increasing temperature, which is known as the linear ptc effect.

Non-linear ptc effect The material undergoing phase change will exhibit a sharp increase in resistance along the narrow temperature range of several to ten orders of magnitude, namely the nonlinear ptc effect, which is exhibited by a considerable number of types of conductive polymers. Such as polymer ptc thermistor. These conductive polymers are very useful for making overcurrent protection devices.

The thermistor is used in the same way as a normal fuse and is used in series in the circuit. The thermistor can also be used as an electronic circuit component for meter line temperature compensation and temperature difference cold junction temperature compensation. The automatic gain control can be realized by the self-heating characteristics of the NTC thermistor, and the RC oscillator stabilization circuit, the delay circuit and the protection circuit are formed.