What is a thermocouple? Thermal resistor and the difference between them

Both thermocouples and thermal resistors are commonly used temperature measuring components, and they are contact temperature measuring components. However, there are significant differences between the two. The following will introduce the temperature measurement characteristics, wiring methods, and temperature measurement range.

1. Different temperature measurement characteristics
Thermocouples are composed of two different conductors/metals, A and B, and form a circuit. When the measured temperature changes, a thermoelectric potential will be generated in the circuit to form a thermal current, which is the so-called thermoelectric effect.

Thermal resistors measure temperature based on the characteristic that the resistance value changes with temperature, that is, the change in temperature is represented by the change in resistance value. In other words, thermal resistors are a pure metal, such as commonly used platinum, copper, nickel, etc. Commonly used thermal resistors are PT100, PT1000, etc.

2. Wiring method
Thermocouples are two-wire systems, while thermal resistors can be two-wire, three-wire, or four-wire systems.
3. Different temperature measurement ranges
Thermistors can generally measure up to 200°C, and some can measure up to -100 to 500°C; while thermocouples can measure up to 1000°C