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Temperature Measurement · Glossary

What are Thermocouple Types?

letter designationsTemperature Measurement

Thermocouple types are letter codes such as J, K, T, N, E, R, S and B, each a standard pair of alloys with its own range and curve.

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Thermocouple Types Explained

Base metal types (J, K, T, N, E) are used up to about 1200 °C. Noble metal types (R, S, B) use platinum and rhodium for higher temperatures and better stability.

Type K is the general purpose choice; type N is more stable at high temperature; type T suits low temperatures.

Thermocouple Types: Typical Values

J (iron / constantan)up to about 750 °C
K (nickel chromium / nickel aluminium)up to about 1200 °C
N (nicrosil / nisil)up to about 1200 °C
T (copper / constantan)−200 to about 350 °C
E (nickel chromium / constantan)up to about 900 °C, highest output
R and S (platinum rhodium / platinum)up to about 1600 °C
B (platinum rhodium / platinum rhodium)up to about 1700 °C
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Calculators for Thermocouple Types

CalculatorThermocouple TableFree online calculator with formula and worked example.CalculatorThermocouple CalculatorFree online calculator with formula and worked example.

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ToolThermocouple Color CodesFree interactive tool on instrumentationblog.in.

Frequently Asked Questions

What are Thermocouple Types?

Thermocouple types are letter codes such as J, K, T, N, E, R, S and B, each a standard pair of alloys with its own range and curve.

Can I swap a type J sensor for type K?

Only if the transmitter is reconfigured; the curves are different.

Why does type K drift at 250 to 550 °C?

Short range ordering in the alloy changes its output; type N was developed to reduce this.

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All temperature measurement terms · Full glossary A to Z

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