Thermocouple types

Thermocouple types:

A Thermocouple is one of the most widely used temperature sensors in industrial processes. It works on the Seebeck Effect, where two dissimilar metals joined together generate a small voltage proportional to temperature. Different thermocouple types are designed for specific temperature ranges, environments, and accuracy requirements.

Common Thermocouple Types

Type K (Chromel – Alumel)

Range: -200°C to 1372°C

Most widely used thermocouple

Excellent for general industrial applications

Good oxidation resistance

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Type J (Iron – Constantan)

Range: -210°C to 1200°C

Suitable for reducing atmospheres

Common in older industrial systems

Iron element can oxidize at high temperatures

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Type T (Copper – Constantan)

Range: -200°C to 400°C

Excellent low-temperature accuracy

Ideal for cryogenic applications

Stable and reliable

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Type E (Chromel – Constantan)

Range: -200°C to 1000°C

Highest output voltage among base metal thermocouples

High sensitivity

Suitable for low-temperature measurements

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Type N (Nicrosil – Nisil)

Range: -200°C to 1300°C

Improved stability over Type K

Excellent resistance to high-temperature oxidation

Long service life

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Type R (Platinum-Rhodium / Platinum)

Range: 0°C to 1768°C

High accuracy

Excellent long-term stability

Used in high-temperature furnaces

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Type S (Platinum-Rhodium / Platinum)

Range: 0°C to 1768°C

Standard for calibration laboratories

Extremely stable and accurate

Used in glass and pharmaceutical industries

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Type B (Platinum-Rhodium)

Range: 600°C to 1820°C

Highest temperature capability

Excellent for extreme heat applications

Common in steel and metallurgical industries

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Industrial Applications

Furnaces & Kilns

Heat Treatment Plants

Oil & Gas Industry

Power Plants

Chemical Processing

Automotive Testing

Aerospace Industry

Research Laboratories

Engineering Insight

For most industrial temperature measurements, Type K Thermocouples are the preferred choice due to their wide temperature range, durability, and cost-effectiveness. However, for extremely high temperatures above 1600°C, noble metal thermocouples such as Type R, S, and B provide superior accuracy and long-term stability.