To distinguish between thermocouples and thermal resistors, you can pay attention to the following aspects:

Principle difference:

A thermocouple is a temperature sensor based on the thermoelectric effect, which uses conductive wires connected by two different materials. When the connection point of the two wires is at different temperatures, an electromotive force is generated to measure temperature.

Thermal resistance is a resistance based temperature sensor, it is a resistance element, its resistance value changes with the change of temperature.

Material differences:

Thermocouples are usually made of wires of two different metals or alloys, common materials include copper-copper-nickel alloys, iron-copper-chromium alloys, etc.

Thermal resistors generally use conductive materials, the most common being platinum (PT100, PT1000) and copper (CU100).

Resistance change:

The output of a thermocouple is based on the thermoelectric effect, and its output is in the form of an electromotive force (voltage) rather than a resistance value. Therefore, you will not measure a change in the resistance value.

The resistance value of a thermal resistor changes with temperature and is usually linear, which means that you can use the resistance value to determine the temperature.

Usage scenario:

Thermocouples are commonly used for high temperature measurement and can operate under extreme temperature conditions, such as furnace temperature measurement in industrial furnaces.

Thermal resistors are commonly used for relatively low temperature measurements, such as laboratory temperature measurements, temperature control systems, etc.

Connection mode:

Thermocouples require specific connection heads and connection wires to ensure accurate temperature measurement.

Thermal resistance is generally connected with ordinary wires, commonly used is two wire, three wire or four wire connection.

In short, thermocouples and thermal resistors are different in principle, materials, output and use scenarios, so they can be distinguished by observing their characteristics and connections. If you need to measure temperature, choose the right sensor according to the specific application scenario.