A thermocouple is equipment used in the measurement of temperature under different conditions. It is used in industries as well by some scientist in their studies. There are various thermocouple types that are commonly recognized and used.
The advantage with thermocouples is that, unlike other temperature measurement equipments used, thermocouples generate their own power and do not need any external form of excitation for them to function. They are employed in wide ranges of temperatures. These devices are also applied in the conversion of temperature gradients to generate electricity. Thermocouples are therefore very useful in different areas where the measurement and control of temperatures are needed.
The most common types are J, K, T, B, S, R and E. Each thermocouple is made up of two conductors of different materials generally metal alloys. The metal alloys produce electrical energy in the area where the two conductors are in contact. This point of contact is where one gets to measure the temperature and also the voltage released due to contact of the two conductors. Thermocouples are used as temperature sensors which help in temperature control and measurement.
Type R, S and B are seen as the most stable equipments. The three have a lower sensitivity in comparison to the rest. The three are made up of platinum rhodium alloy or just platinum alloy in each conductor. Their cost is high and therefore not used regularly except in cases of extreme temperature levels. Type R and S are applied in cases where temperatures are at most 1600 degrees while for type B it is used at temperatures which do not exceed 1800 degrees.
Another device is type K which is mostly used since it is relatively cheaper compared to the other devices. It is made of alumel and chrome alloys. Type J share magnetic properties with device K. However, the two differ in that J has a higher degree of sensitivity than K. The only bad side with type J is that it cannot be used in big range of temperatures. Another type similar to K is type N. This device has a higher sensitivity and it is applied in measurement and control of temperature under high conditions.
Devices T and E are yet another set. These two differ from type K, N and J in that they do not have any magnetic properties that are; they are not made up of magnetic alloys. Since they are not magnetic, this feature makes them the best to use in finding temperature differentials. For instance, type T is made of constantan and copper conductors which lack magnetic properties.
Types C and M are applied in high temperature levels. They are applied in vacuum heaters since of their property of measuring and controlling high temperatures. The two are not mostly used like the other devices.
In order to decide on the most suitable device to use among the list of the thermocouple types, one needs to have information on the degree of sensitivity and consistency of the device. Some other factors include the cost and the condition of the atmosphere. With information regarding these factors, one can comfortably choose the most suitable device too employ in the measurement and control of temperature.
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