Temperature plays an important role in many scientific and industrial processes. As such, we need ways to accurately measure temperatures – and thermocouples are one of the tools that allows us to do so.
In this guide, we’ll explain what thermocouples are, how they work, and much more.
What are thermocouples?
Thermocouples are temperature sensors that provide quick and reliable feedback in a variety of settings. Additionally, thermocouples are available in a wide range of designs and configurations, making it easy for engineers to find and choose a suitable option for their applications.
How do thermocouples work?
Thermocouples operate on the principle of the Seebeck effect, discovered by German physicist Thomas Johann Seebeck in 1821.
This principle states that a voltage is generated when two dissimilar metals are joined at one end and exposed to a temperature gradient.
The voltage is proportional to the temperature difference between the measuring junction – the place where the metals touch – and the reference junction, usually at the other end of the thermocouple.
What are the benefits of thermocouples?
There are many reasons why you might choose to use thermocouples for temperature measurement, including:
- Affordability: Thermocouples are typically more affordable than other temperature measurement options like Resistance Temperature Detectors (RTDs), making them a cost-effective choice for budget-conscious projects.
- Fast response times: Thanks to their lower mass and smaller size, thermocouples boast relatively quick response times. This enables them to provide rapid temperature measurements – essential in rapid processes that require real-time feedback.
- Durability: Thermocouples are remarkably resistant to mechanical stress, vibration and shock. This resilience makes them suitable for harsh environments in which reliability is a necessity.
What are the different types of thermocouples?
Thermocouples are classified into types based on the metals they’re made of, including:
- Type J – made from Iron and Constantan
- Type K – made from Chromel and Alumel
- Type T – made from Copper and Constantan
- Type N – made from Nicrosil and Nisil
Each type has temperature ranges, sensitivities and characteristics that make them more suitable for different applications.
What are the applications of thermocouples?
Thermocouples are some of the most widely used temperature sensors on the planet. You can find them being used in a huge range of settings including:
- Aircraft sensors
- Home appliances
- Industrial processes
- Automotive sensors
- Satellites and spacecraft
- Electric power generation
- Food and beverage processing
- Furnace monitoring and control
The capacity to accurately measure temperature is vital in many industries and context. Thermocouples provide an affordable, durable and effective way to do this, which is why they’re favoured by engineers across the world.
