As temperature probe experts Process Parameters explains (https://www.processparameters.co.uk/thermocouples-sensor/what-is-a-thermocouple/), thermocouples are two-wire electrical devices widely used in aerospace, automotive, and electronics industries. They are commonly used in measurements of temperature and pressure.
When one metal is exposed to an extremely hot source, it produces electrons. These electrons then travel along the conductive wire, which is connected to a lead close to an extremely cold source.
This process results in an electrical current between the two leads, one positive and the other negative, depending on their respective temperatures. In this article, we will go over the basic principles of thermocouples.
A Thermocouple’s Working Principle
A thermocouple is very useful in measuring temperatures. It is composed of two wires joined together at one end. The other ends of these wires are connected to a meter or other instrument for reading their temperatures. The thermocouple works by measuring the difference between the cold junction and the hot junction.
The hot junction is generally exposed to an extremely hot source such as a flame, a welding torch, or a molten material poured from its container. The copper wire from the sensor is connected to this extremely hot source while the cold junction is kept at a lower temperature than the hot side by using an ice bath or some other means of cooling it down.
When this happens, electrons start to travel through the copper wire towards its colder end, creating an electrical current in its path. This process continues until all the electrons have travelled through and reached their destination, creating an electrical current between both ends of the thermocouple wire, one positive and the other negative, depending on their respective temperatures.
Reading a Thermocouple Wire
When using a thermocouple, you will have to read its temperature from either one of its two leads, positive or negative, depending on where you’re taking your temperature measurement from, either from its cold junction or hot junction, respectively.
For example, if you’re taking your measurement from anywhere on your thermocouple wire, you will have to use a thermometer or a temperature gun to read its temperature. If you are taking your measurement from the hot junction, you can read its current temperature by simply touching it with your finger.
Checking the Thermocouple Wire
If the wires in your thermocouple have been damaged during transport or installation, then there is no need to worry as it is relatively easy for them to be repaired or replaced. If the ends of the wires are not damaged, you can check for any cracks that may have formed and replace them should they be found.
This is done by heating both ends of the wires with a torch and checking for any cracks that may have formed at either end. Once these cracks are found, they can be repaired using epoxy resin glue or by soldering them together using copper wire solder paste (which works better than solder).
Replacing the Thermocouple
For thermocouples that have been damaged or worn out, it is best to replace them as soon as possible. They may still be able to function if they are replaced soon enough, but the longer they are left, the more likely they are to break down and lead to device failure.
If you have a spare thermocouple wire, you can use this instead of replacing the entire device. However, it is recommended that you replace the entire device if possible.
Replacing the entire device is a fairly easy process and can be done by simply removing the old thermocouple from the device, cutting off any damaged wires, and soldering in a new one.
If you don’t have any spares, you will need to buy new ones from an electronics retailer or online. You can also ask for help from an expert at a repair shop or one of the professional repair services.
3 Quick Applications of Thermocouples
Automotive Industry
The automotive industry uses thermocouples to measure temperature. These are used in the engine, air conditioning, and other systems. It is also used in fuel systems for cars as well as motorcycles.
Aerospace Industry
The aerospace industry uses thermocouples to measure temperature across various objects, engines, and control surfaces. They are also used to monitor the temperature of multiple fluids such as fuel, hydraulic fluid, and others.
Electronics Industry
The electronics industry uses thermocouples in many applications, including power supplies, sensors, and batteries. They are also used in various electronic components like resistors and capacitors.
What Is The Basic Principle of Thermocouple?
Thermocouples are widely used in industries to measure temperature. They work on the principle of temperature-coefficient of resistance and are an instrumental tool in measuring temperatures and electrical resistance.
- Supercharging SaaS Analytics with On-Prem to Cloud Migration - November 12, 2025
- Data-Driven Decisions: Optimizing ROI with Construction Equipment Fleet Management - October 12, 2025
- Supercharge Marketing ROI: Unlocking Analytics with Process Automation Solutions - September 23, 2025
