The thermocouple is a commonly used temperature measurement element in temperature measurement instruments. It directly measures temperature and converts the temperature signal into a thermoelectric potential signal, which is then converted into the temperature of the measured medium by an electrical instrument (secondary instrument). The shapes of various thermocouples often vary greatly due to different requirements, but their basic structures are roughly the same. They usually consist of main components such as thermoelectric electrodes, insulating protective tubes, and junction boxes. They are typically used in conjunction with display instruments, recording instruments, and electronic regulators.