A temperature sensor is a sensor that senses temperature and converts it into an available output signal. The temperature sensor is the core part of the temperature measuring instrument and has a wide variety. According to the measurement method, it can be divided into two types: contact type and non-contact type. According to the characteristics of sensor materials and electronic components, it can be divided into two types: thermal resistance and thermocouple.
Temperature sensors are the earliest developed and most widely used sensors. The market share of temperature sensors far exceeds that of other sensors. From the beginning of the 17th century, people began to use temperature to measure. With the support of semiconductor technology, semiconductor thermocouple sensors, PN junction temperature sensors and integrated temperature sensors have been developed in this century.
Conductors of two different materials, such as being connected to each other at a certain point, heat the connection point, and a potential difference occurs in a portion where they are not heated. The value of this potential difference is related to the temperature of the measurement point of the unheated part, and is related to the material of the two conductors. This phenomenon can occur over a wide temperature range. If the potential difference is accurately measured and the ambient temperature of the unheated portion is measured, the temperature of the heating point can be accurately known. Because it must have two conductors of different materials, it is called a "thermocouple." Thermocouples made from different materials are used in different temperature ranges and their sensitivity varies.
The thermocouple sensor has its own advantages and disadvantages. It has low sensitivity, is susceptible to environmental interference signals, and is susceptible to temperature drift of the preamplifier. Therefore, it is not suitable for measuring small temperature changes. Because the sensitivity of the thermocouple temperature sensor is independent of the thickness of the material
