In recent years, the intelligent process of industrial production in our country and the rapid increase of the intelligent electronic information industry have promoted the rapid development of sensor shopping malls rise. As a key type of sensors, temperature sensors account for more than 40% of the total sensor requirements. The temperature sensor is a semiconductor device that uses NTC's resistance value to change with the ambient temperature, converts non-electrical physical quantities into electrical quantities, and then can accurately measure and automatically control the ambient temperature. The temperature sensor has a very wide range of uses, and can be widely used for ambient temperature measurement and control, temperature compensation, flow rate, flow and wind speed measurement, liquid level indication, ambient temperature measurement, ultraviolet and infrared light measurement, microwave power measurement, etc. In the fields of color TV, computer color display, switching power supply, water heater, refrigerator, kitchen equipment, air conditioner, car, etc. In recent years, the rapid advancement of the car's smart electronics and consumer electronics professions has promoted the rapid increase in the demand for temperature sensors in China.
The temperature sensor is the earliest developed and the most widely used sensor. The market share of temperature sensors greatly exceeds that of other sensors. From the beginning of the 17th century, people began to use ambient temperature for measurement. With the support of semiconductor technology, this century has successively developed semiconductor thermocouple and compensation wire sensors, PN junction temperature sensors and integrated temperature sensors.
If the conductors of two different materials are connected to each other at a certain point, heating this connection point will show a potential difference at the part where they are not heated. The value of this potential difference is related to the ambient temperature of the measurement point of the unheated part, and the raw materials of these two conductors. This phenomenon can be displayed in a wide range of ambient temperature. If the potential difference is accurately measured, and then the ambient temperature of the unheated part is measured, the ambient temperature of the heating door can be accurately known. Because it must have two conductors of different materials, it is called "thermocouple and compensation wire". Thermocouples and compensating wires made of different materials are used in different ambient temperature scales, and their sensitivities are also different.
Thermocouples and compensating wire sensors have their own strengths and weaknesses. Their sensitivity is relatively low. They are easily affected by environmental disturbance signals, and they are also simply affected by the ambient temperature drift of the preamplifier, which is not suitable for measuring small environments. The temperature changes. The reason is that the sensitivity of the thermocouple and compensation wire temperature sensor is not related to the thickness of the data