Thermistors are a type of sensitive components, which are divided into positive temperature coefficient thermistors (PTC) and negative temperature coefficient thermistors (NTC) according to different temperature coefficients. A typical feature of a thermistor is that it is sensitive to temperature and exhibits different resistance values at different temperatures. Positive temperature coefficient thermistors (PTC) have larger resistance values at higher temperatures, and negative temperature coefficient thermistors (NTC) have lower resistance values at higher temperatures. They are both semiconductor devices.