How to distinguish between thermocouple and thermistor

How to distinguish between thermocouple and thermistor
First of all, let's introduce thermocouples. Thermocouples are the most commonly used temperature devices in temperature measurement. Their important features include a wide measurement range, stable functionality, simple structure, good static response, and the ability to transmit 4-20mA electrical signals remotely, making it easy to actively and collectively control.

The temperature measurement principle of thermocouples is based on the thermoelectric effect. Connecting two different conductors or semiconductors into a closed circuit, when the temperature difference at the two junctions occurs, a thermoelectric potential will occur in the circuit. This phenomenon is called thermoelectric effect, also known as Seebeck effect.

The thermoelectric potential generated in a closed circuit consists of two types of electric potentials; Thermoelectric potential and war potential. Thermoelectric potential refers to the electric potential that occurs at the two ends of a unified conductor due to temperature differences. Different conductors have different electron densities, so their electric potentials are not the same. War potential, literally speaking, refers to the electric potential formed when two different conductors are at war, due to the difference in their electron densities, there is a certain dispersion of electrons. When they reach a certain equilibrium, the magnitude of the war potential depends on the characteristics of the two different conductors and the temperature at their point of war.

There is a standard scale for the thermocouples currently in use, which is divided into eight different divisions: B, R, S, K, N, E, J, and T. The thermocouples can measure temperatures ranging from as low as minus 270 degrees Celsius to as high as 1800 degrees Celsius. Among them, B, R, and S belong to the platinum series thermocouples because platinum is a precious metal and is also known as precious metal thermocouples.

And the rest are called cheap metal thermocouples. There are two types of thermocouple constructions: general type and armored type. Typical thermocouples are composed of various components such as hot electrodes, insulation tubes, maintenance sleeves, and junction boxes. Armored thermocouples are a sturdy combination of thermocouple wires, insulation materials, and metal maintenance sleeves that are disassembled and stretched through processing.