Different Thermocouple Types & Ranges with Comparison

A Thermocouple is one type of temperature sensor used for measuring temperature, and it has two different metal wire legs. These two metal wire legs are connected together at the end of the circuit to form a junction. So the temperature can be calculated at this junction. As the junction understands a temperature modify then the voltage will be created. The created voltage can be modified with this sensor reference table for temperature calculation. The applications of thermocouples mainly include numerous scientific, OEM, industrial applications. The industrial applications mainly include gas (or) oil, generation of power, cement, pharmaceutical, biotech, paper & soft tissues. This sensor is also employed in home appliances namely toasters, stoves, and heaters. Usually, the usage of these devices is high due to their features like a limit of high-temperature, low-cost, durable in nature, and a wide range of thermocouples. This article discusses an overview of thermocouple types.

Different Thermocouple Types & Ranges

Thermocouples are classified into different types namely Type-K, Type-J, Type-T, Type-E, Type-N, Type-S, Type-R, and Type-B. These types of thermocouples have their own characteristics. But, a thermocouple is surrounded by a safety sheath for separating it from the environment.  This safety sheath will reduce the corrosion effect drastically.

Before talking about the thermocouple types, it must be noted that these are frequently surrounded in a safety cover for isolating them from the environment. This safety cover will reduce the effect of rust drastically.

J- Type Thermocouple

This is the most frequently used thermocouple, and it consists of positive (Iron) and negative (Constantan) legs. The applications of this thermocouple include reducing, vacuum, oxidizing and inert environments. The temperature range of this thermocouple is low and lifespan is lesser at high-temperature compare with K-type. It is equal to the K-Type in conditions of reliability and expense.

K- Type Thermocouple

The k-type thermocouple is the most common type of thermometer, and it consists of positive (Chromel) and negative (Alumel) legs. This thermocouple is suggested for inert or oxidizing atmospheres up to 2300 ⁰F Cycling above & but not suggested for below 1800 ⁰F due to EMF variation from hysteresis. It is quite stable as well as accurate at high temperatures.

N-Type Thermocouple

The N-Type thermocouple consists of positive (Nicrosil) and negative (Nisil) legs. It has superior resistance for degradation due to the cycling of temperature, hysteresis, and green rot than the K-Type. It is normally very expensive.

T-Type Thermocouple

The T-type thermocouple consists of positive (Copper) and negative (Constantan) legs. The applications mainly include oxidizing, reducing, in the vacuum, & inert environments. It maintains stable resistance to decomposition in most environments as well as high stability on sub-zero temperatures.

E-Type Thermocouple

The E-type thermocouple consists of positive (Chromel) and negative (Constantan) legs, and it is not focused on oxidization in atmospheres. This type also has the maximum EMF per degree like any typical type of thermocouple. But, this type must be defended from sulfurous environments.

S-Type Thermocouple

The S-type thermocouple is used in extremely high-temperature applications. The applications of this mainly involved in the Pharmaceutical as well as BioTech industries. Sometimes, it is used in low- temperature applications due to stability and high accuracy.

B-Type Thermocouple

The B-Type thermocouple is extremely used in high-temperature applications, and the temperature limit of this is highest than other types of thermocouples discussed above. It maintains a high level of precision as well as constancy at very high temperatures.

R-Type Thermocouple

The R-Type thermocouple is applicable for high-temperature. It consists of a high percentage of (Rhodium) chemical elements than the S-Type which will make it more costly. This type is very comparable to the S-Type in terms of the act. Sometimes, it is used in low- temperature applications due to its stability and high accuracy.

Comparison of Thermocouple Types

The comparison of Thermocouple types includes the following.

For J-Type

Composition: It has Iron (+) and Constantan (-) legs

Temperature Range: The temperature range of J-Type ranges from –210 to +1200 °C

Accuracy: The accuracy for J-type is Typical: +/- 2.2C (or) +/- .75% particular error limits: +/- 1.1C (or) 0.4%

Sensitivity: The sensitivity of J-Type is 50-60 µV/°C

For K-Type

Composition: It has Chromel (+) and Alumel (-) legs

Temperature Range: The temperature range of K-Type ranges from 200 to 2300^o F and 95 to 1260 ^o C

Accuracy: The accuracy for K-type is Typical: +/- 2.2C (or) +/- .75% particular error limits: +/- 1.1C (or) 0.4%

Sensitivity: The sensitivity of K-Type is 28 – 42 µV/°C

For N-Type

Composition: It has Nicrosil (+) and Nisil (-) legs

Temperature Range: The temperature range of N-Type ranges from –250 to +1300 °C Accuracy: The accuracy for N-type is Typical: +/- 2.2C (or) +/- .75% particular error limits: +/- 1.1C (or) 0.4%

Sensitivity: The sensitivity of  N-Type is 24 – 38 µV/°C

For T-Type

Composition: It has Copper (+) and Constantan (-) legs

Temperature Range: The temperature range of T-Type ranges from –330 to 660 °F & ––200 to 350 °C

Accuracy: The accuracy for T-type is Typical: +/- 2.2C (or) +/- .75% particular error limits: +/- 1.1C (or) 0.4%

Sensitivity: The sensitivity of T-Type is 17 – 58 µV/°C

For E-Type

Composition: It has Chromel (+) and Constantan (-) legs

 Temperature Range: The temperature range of E-Type ranges from –200 to 1650 °F & ––95 to 900 °C

Accuracy: The accuracy for E-type is Typical: +/- 1.7C (or) +/- 0.5% particular error limits: +/- 1.1C (or) 0.4%

Sensitivity: The sensitivity of E-Type is 40 – 80 µV/°C

For S-Type

Composition: It has Platinum 10% Rhodium (+) and Platinum (-)legs

Temperature Range: The temperature range of S-Type ranges from 1800 to 2640 °F & 980-1450 °C

Accuracy: The accuracy for S-type is Typical: +/- 1.5C (or) +/- .25% particular error limits: +/- 0.6C (or) 0.1%

Sensitivity: The sensitivity of S-Type is 8 – 12 µV/°C

For B-Type

Composition: It has Platinum 30% Rhodium (+) and Platinum 6% Rhodium (-) legs

Temperature Range: The temperature range of B-Type ranges from 2500 to 3100 °F & 1370-1700 °C

Accuracy: The accuracy for B-type is Typical: +/- 0.5% (or) +/- .25% particular error limits: +/- 0.25%

Sensitivity: The sensitivity of B-Type is 5 – 10 µV/°C

For R-Type

Composition: It has Platinum 30% Rhodium (+) and Platinum (-) legs

Temperature Range: The temperature range of R-Type ranges from 1600 to 2640 °F & 870 to 1450°C

Accuracy: The accuracy for R-type is Typical: +/- 1.5C (or) +/- .25% particular error limits: +/- 0.6C or 0.1%

Sensitivity: The sensitivity of R-Type is 8 – 14 µV/°C

Therefore, this is all about thermocouple types. Does this article describe what is thermocouple? how it is works, various thermocouple types, and its comparison. We believe that you have got a better understanding of an overview of this concept. Furthermore, any queries regarding this concept. Please get back to us by commenting in the below comment section.  Here is a question for you, what are the applications of thermocouples?