What is a thermocouple?

Thermocouples are a very useful and widely used temperature measurement tool, commonly used in fields such as science, industry, and engineering environments.
They have advantages such as small size and short response time, and can be used in various hazardous or challenging environments. They can also quickly and accurately measure extreme temperatures (in the temperature range of 270 to 2500 ℃, depending on the configuration).
Despite their outstanding features, their design is very simple, providing powerful functionality while also being cost-effective. Usually, the letters J, K, L, N, or T are used to define different types of thermocouples, which have different characteristic limits. Some thermocouples use special materials that can withstand high temperatures and challenging environments; And others are relatively weak, with lower manufacturing costs and only suitable for use in conventional environments.

The purpose of thermocouples
As mentioned above, a thermocouple is a sensor tool primarily used to measure unknown temperatures of various entities, components, or substances.
It is worth noting that thermocouples are composed of at least two wires of different metal materials. When they are connected together to form a circuit, they form two separate electrical terminals. One end is located at the unknown temperature to be measured ("hot end" or "measurement end"), and the other end is connected to a known and stable temperature object ("cold" or reference end).
At any given time, the temperature difference between these two terminals will generate voltage within the circuit, and its subsequent current can be used to measure the temperature of unknown or "hot" contact points.