When do you need a thermocouple and what kind of thermocouple do you need?

When do I need a thermocouple sensor?

Thermocouples are needed when high temperatures need to be measured or temperatures in hazardous environments, such as environments with high vibration or with toxic gasses. They are less common when high precision measurement is required for temperature ranges varying from 0 to 300°C.  For this temperature range RTDs are more accurate. 

What kind of thermocouple sensor do I need?

This depends on the temperature you need to measure. The thermocouple alloys are described as types. For example, a type K thermocouple alloy contains a NiCr-Ni junction, providing the widest operating range of all thermocouples. Below you can find a list of temperature ranges for each thermocouple type. When choosing a thermocouple for your application, keep in mind that the diameter of the sensor can have an impact on the application range and the lifetime of the sensor.

Thermocouple type Useful application range
E -270 .. +900°C
J -210°C .. +760°C
K -270°C .. +1260°C
N -270°C .. +1260°C
R -50°C .. +1480°C
S -50°C .. +1480°C
B 0°C .. +1700°C
T -270°C .. +370°C