Home Technology Thermocouple Sensor What It Is, Types And Purchase Guide

Thermocouple Sensor What It Is, Types And Purchase Guide

by Abhay Choubey

A thermocouple is a well-known temperature measuring device composed of several types of sensors from which consumers can choose. From Type K to Type J, Type T and other thermocouples, understanding the differences and purchasing a thermocouple that will fit your next Arduino thermocouple project can be a daunting task!

But don’t worry, in this guide I’ll help you by explaining:

What is a thermocouple?

How does a thermocouple work?

What types of thermocouples are there?

How to choose a thermocouple

How do I use a thermocouple with an Arduino?

What is a thermocouple? definition

A thermocouple is a two-piece metal sensor that measures temperature. Two metal parts are welded at one end to form a joint where the temperature is measured.

The photo above shows a Type K thermocouple available from Seeed! Click here to find out more!

How do thermocouples work?

How thermocouples work

The thermocouple works according to the Seebeck effect (also called the thermoelectric effect), a principle discovered in the 18th century by the German physicist Thomas Johann Seebeck.

The Seebeck effect shows that when two different metals are held together at two points of contact, an electromotive force (EMF) occurs.

To better understand this principle of operation, let’s take a look at the thermocouple circuit!


Explanation of the thermocouple diagram

The diagram below shows the circuitry commonly found in thermocouples. Here’s how thermocouples work in this figure:

Two pieces of metal are welded at one end to form a joint.

Thermal grease is a heat source that creates temperature.

When the temperature changes between metals, a voltage difference arises.

He then consults the thermocouple lookup tables to interpret the voltage for the calculated temperature.

What are thermocouples used for?

Now that we understand how thermocouples work, let’s see how you can use them.

Thermocouples are used not only in industry, but also in household appliances:

Industrial Application:

Measurement of metal temperature

Temperature measurement of furnaces, motors and technological processes

Food industry; Milk pasteurization and cryonics

Daily Applications:

Thermocouple furnace



In general, thermocouples are a type of temperature sensor widely used for measurement and control, although there are differences from other types of temperature sensors such as RTDs and thermostats. We’ll talk about the differences later.

What is the difference between thermocouple, RTD, thermistor?

A thermocouple can be compared to RTDs and thermistors because these are common types of sensors used to measure temperature.

In addition to comparing thermocouples, thermocouple manufacturers, and thermistors above, there is also a lot of discussion about the differences between thermocouples and thermopiles.

For a better understanding, there is only one important difference to be aware of:

A thermocouple is a two-part metal sensor used to measure temperature.

A thermopile is a device that converts thermal energy into electrical energy.

What types of thermocouples are there?

Now that you understand what thermocouples are and how they work, let’s take a closer look at what types of thermocouples?

There are 8 types of thermocouples, which are classified into “base metals” and “precious metals”, namely:

Base metal thermocouple type:

Type of precious metal thermocouple:

Type K thermocouple (most popular)

The most common type of thermocouple is without a doubt the type K thermocouple. It is known for its wide temperature range and durability, which is why it is a must for many!

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