How it Works and Types of Thermocouples

How it Works and Types of Thermocouples
Thermocouple is a type of temperature sensor used to detect or measure temperature which is quite popular and commonly used in industry.

Some of the advantages of thermocouples are their fast response to temperature changes and also their wide operational temperature range, ranging from -200˚C to 2000˚C.

Apart from its fast response and wide temperature range, the thermocouple is also resistant to shock or vibration and is easy to use.

The way a thermocouple works is quite easy and simple. Two different types of metal conductors are joined at the ends. One type of metal conductor in the thermocouple will function as a reference with a constant (fixed) temperature while the other is a metal conductor that detects hot temperatures.

A thermocouple is a measuring instrument that uses thermo-electric voltage to detect temperature changes in an electronic device.

To work, the thermocouple uses two types of metal conductors. Where the two conductors are made of metal with different materials.

To be able to operate, the metal will be designed to be fused at both ends (junction). Then when the electric voltage propagates through the junction. Then the tool will detect if a heat absorption or release event occurs.

It could be said that the response is quite accurate, easy to read, and the tool also has a wide measurement range.

So it is not surprising that the use of thermocouples as temperature transducers is increasingly popular and widely used today. Especially used in various types of electronic devices.

How a Thermocouple Works

The way this thermocouple works is quite simple. In this tool, there are two pieces of metal that function as temperature sensors. This sensor device will later function to detect and measure when heat absorption and release occurs in an object later.

When the junction or ends of the wire being wound have the same temperature, the electric current passing through the two junctions will be at zero or neutral.

However, if hot temperatures are applied to the junction, or are connected to an electronic device, then temperature changes will occur and will also be detected on the device.

Every time it receives heat, the thermocouple will produce at least an electrical voltage of around 1 µV – 70 µV. However, to make it more understandable, this value will then be converted into more understandable measurement results. For example, by first converting it to Celsius and so on.

Types of Thermocouples

As a tool commonly used to measure temperature, thermocouples are also divided into various types. The types of thermocouples include the following:

1. K Type Thermocouple

The first type is the K type thermocouple. This type is made from Nickel-aluminum and also Nickel-chromium. Because they have positive and negative properties, Ni-al and Ni-cr are considered very suitable as tools for measuring temperature.

On this K type temperature meter, you will find two probe cables. Where the positive probe is a yellow cable, while the negative probe is a red cable.

Type K thermocouples have a measurement temperature range ranging from -200° Celsius, up to 1250° Celsius. For its own application, this tool is often used for fuel rooms, boilers, reformers and so on.

2. J Type Thermocouple

Type J thermocouples are temperature gauges made of iron and constantan. This measuring instrument has a limited measuring temperature range. Namely, generally only around -40° C to 750° Celsius.

3. Type E thermocouple

The negative part of the type E thermocouple is made of costant, while the positive part is nickel-chromium. This measuring instrument has a fairly wide measuring temperature range, which generally starts from -200° Celsius to 900° Celsius.

4. N Type Thermocouple

Type N temperature measuring instruments are made of nisil material for the negative part. Meanwhile, the positive part is Nicrosil. This type of thermocouple has a measuring temperature range from 0° Celsius to 1250° Celsius.

This type N temperature measuring instrument has several advantages that are worth considering. Among them are that the measurement results are stable and have high resistance to oxidation. And what is no less important is that it can also be used to measure high temperatures even without using platinum.

5. U Type Thermocouple

In a U-type thermocouple, the positive part is Cooper or copper. Meanwhile, the negative part is made of Cooper Nickel. The measuring temperature range of this tool is quite low, starting from -200° C, up to just 350° C.

6. T Type Thermocouple

This measuring instrument has a fairly wide measuring temperature range, namely it can measure temperatures from 0°C to 1450°C.
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