A thermocouple is a device that converts temperature into a voltage. This allows you to measure the temperature of various substances.
As Process Parameters explains (https://www.processparameters.co.uk/thermocouples-sensor/what-is-a-thermocouple/), there are many different types of thermocouples, but they all operate in the same manner.
In this post, we’ll discuss how thermocouples work and how you can use them in your lab.
What is a thermocouple?
When discussing thermocouples, they can be described as useful temperature measurement tools mainly used in engineering, industrial, and scientific sectors.
Since they come in small sizes and have a fast response time, they can be used for all types of challenging fields while providing the ability to accurately and swiftly measure very extreme temperatures. Mostly between 270 to 2500 degrees.
Besides their impressive ability, they are simple tools that are extremely cost-effective and highly robust.
Thermocouples come in different types and they are normally defined by letters like T, K, L, N, or J.
This way, they provide different extremes that offer key characteristics. For instance, some are made of materials that can work well under high temperatures and challenging environments.
Some thermocouples are cheap to make, less rugged, and designed for use in less extreme environments.
What do thermocouples do?
As mentioned above, thermocouples are designed to take measurements of unknown temperatures of some substances, components and physical bodies.
Thermocouples are comprised of two wires at least, of different metals that when combined, they form a circuit and create two electrical junctions that are separate.
One junction is found where an unknown temperature requires to be measured. The other junction is connected to a body that has a stable and known temperature.
The temperature differences that is found between these two junctions create voltage around the circuit. This current flow is useful as it measures at the hot point of contact.
How thermocouples work
Thermocouples work based on thermoelectrics. When there is a change in temperature at the hot junction in relation to the cold junction, this creates a change in voltage along a closed circuit that has dissimilar metal wires
For instance, when holding a frying pan, heat travels up its handle as it moves to the cold end of your hand. Electricity also makes this same journey.
This happens since there are heat differences in the two junctions at the circuit. The temperature differentials at each junction result in electromotive forces that create current.
Thermocouples come attached with a voltmeter that is used to measure the current as long as it already knows the stable start temperature of the cold end.
Thermocouples use the voltage readings to calculate the exact temperature of the hot junction.
Keep in mind that if both junctions have the same temperature, the electromotive forces created at each junction will cancel each other out.
Types of thermocouples
You will find various types of thermocouples on the market today and they all handle various types of application scenarios and different temperature ranges.
Thermocouples are differential by letters. The most common types are T, K, L, N and J. these letters represent different metal combinations used in the circuit junctions.
K-type thermocouples
This is the most commonly used thermocouple in the industries. They are made from combining nickel-based wires that result in a thermocouple that is cost-effective
They are reliable and durable and have various operating temperatures. They are mostly within the -200 to +1260 degrees Celsius range.
J type thermocouple
These types of thermocouples are also widely used, but their temperature range is narrower as it ranges between -40 to +750 degrees Celsius
N-type thermocouple
These are made of nicrosil-nisil alloys and have many similar properties to the K-type thermocouple.
Its operating temperature ranges between -270 to +1300 degrees Celsius.
Uses of thermocouples
Thermocouples for thermostats
Thermostats have thermocouples as the main components for them to work properly as they are the major components in thermostats as the readings of the thermocouples trigger the thermostat to work.
Thermocouples for medical thermometers
Thermometers used in the hospitals and other hospital equipment use thermocouples. They are designed to assist in fast and accurate temperature readings of heat-critical machinery and patients.
Thermocouples for vehicle diagnostics
When it comes to the transport industry, thermocouples are widely used in aerospace and automotive industry in monitoring and managing crucial temperatures.
So what is a thermocouple? How do they work? Final Thoughts
When it comes to choosing the best thermocouple for your needs, various factors come in play such as the available formats, configurations and cost of the thermocouple in the market today.
