Thermocouple
A thermocouple is a temperature sensor made of two different metals that generates a voltage proportional to temperature, used in extreme conditions.
What is Thermocouple?
A thermocouple is a temperature sensor consisting of two wires made of different metals joined at one end (the junction). When the junction is heated or cooled, it produces a small voltage (the Seebeck effect) that is proportional to the temperature. Common types include Type K (-200°C to +1,260°C) and Type T (-200°C to +350°C).
Thermocouples are rugged, inexpensive, and can measure extremely wide temperature ranges. However, they are less accurate than PT100 RTD sensors and can drift over time, requiring more frequent calibration.
Why It Matters
Thermocouples are used where extreme temperatures or rugged environments make other sensor types impractical — such as autoclaves, ovens, cryogenic storage, and industrial furnaces. Their fast response time also makes them suitable for processes where temperature changes rapidly.
Frequently Asked Questions
When should I use a thermocouple instead of a PT100?
Use thermocouples for extreme temperatures (above 600°C or below -200°C), very fast response time requirements, or rugged environments where the sensor may be damaged. Use PT100 for applications requiring high accuracy (±0.05%) and long-term stability, such as pharmaceutical monitoring.