Thermocouple Types

Over the years a selection of the most popular combinations of wires / legs has been established based on a range of criteria including cost, availability, convenience, melting point, chemical properties, stability, and output requirement.

The thermocouple ‘type’ is usually chosen via the performance requirement in terms of temperature range and responsiveness / sensitivity.

Our standard thermocouple types are listed below, however other types are available for low sensitivities and feature lower resolutions, primarily types R, S and B.

MICC Standard Range

Code

Notes

K

Most suited to oxidising atmosphere, it has a wide temperature range and is the most commonly used.

T

Excellent for low temperature and cryogenic applications. Good for when moisture may be present

J

Commonly used in the plastics moulding industry. Used in reducing atmosphere as an unprotected thermocouple sensor. NB. Iron oxidises at low (rusts) and at high temperature

N

Very stable output at high temperature it can be used up to 1300°C. Good oxidation resistance. Type N stands up to temperature cycling extremely well.

E

Has the highest thermal EMF output change per °C. Suitable for use in a vacuum or mildly oxidising atmosphere as an unprotected thermocouple sensor.

Other Ranges

R

Used for very high temperature applications. Used in the UK in preferences to Type S for historical reasons. Has a high resistance to oxidation and corrosion. Easily contaminated, it normally requires protection

S

Type S has similar characteristics to Type R as shown directly above.

B

Type B although similar characteristics to Type S and R it is not as popular. Generally used in the glass industry.

G

Formerly known as Code W. Tungsten Rhenium alloy combinations offer reasonably high and relatively linear EMF outputs for high temperature measurement up to 2600°C and good chemical stability at high temperatures in hydrogen, inert gas and vacuum atmospheres. They are not practicable for use below 400°C. Not recommended for use in oxidising conditions

C

Formerly known as Code W5.

D

Formerly known as Code W3.

 

Thermocouple Types Temperature Ranges

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