What are the two manifestations of temperature sensors?

Temperature sensor is a widely used sensor and the core part of temperature measurement instruments. It has a wide variety of varieties and a wide range of application fields. According to different measurement forms, temperature sensors have multiple types. In daily use, the common forms of expression include thermocouples and thermistors.

Let's take a closer look at the two manifestations of temperature sensors:

1. Thermocouple: Composed of two different types of metal wires welded together, such as NiCr Ni (K-type), it works by utilizing the thermoelectric effect. Two different types of metal wires form a closed circuit, and there is a temperature difference between the two different conductors, producing electric heat. Therefore, a current of a certain magnitude is formed in the circuit, which is called thermoelectric phenomenon.

2. Thermistor: The measurement principle is different from the thermocouple measurement method. Thermistor is a widely used and economical temperature sensor. Due to the composition of mixed oxide ceramic materials, which have a negative temperature coefficient, the resistance decreases with increasing temperature, which is completely opposite to the measurement characteristics of PT100 sensors.

Thermistor sensors are essentially a type of thermistor. The resistivity of metals increases with temperature, so this characteristic is used to measure temperature. Thin film platinum resistors, due to their ultra-thin structure, are equipped with a glass sleeve for protection without affecting the resistance. The PT100 sensor adopts a wound ceramic type, which uses platinum wire to form a spiral shape and then installs it into a ceramic substrate. This sensor structure is very compact, and among all platinum resistance sensors, this structure has high accuracy, long-lasting time, and no aging phenomenon. However, compared to the measurement principle of thermocouple, the reaction time is slower, so it is often used in food technology, especially in laboratory research and development.