Thermocouples are temperature sensors that work based on the principle of the Seebeck effect, which generates a voltage when there is a temperature difference between two dissimilar metals or alloys. There are several types of thermocouples, each with its own combination of metals or alloys, offering different temperature ranges, accuracy levels, and application suitability. Some common types include:
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Type K: Chromel-Alumel (Nickel-Chromium/Nickel-Aluminum) thermocouples. Type K is one of the most common types, suitable for a wide range of applications, and has a temperature range of approximately -200°C to +1350°C.
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Type J: Iron-Constantan thermocouples. Type J is also widely used and has a slightly more limited temperature range compared to Type K, approximately -40°C to +750°C.
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Type T: Copper-Constantan thermocouples. Type T is known for good accuracy and stability at low temperatures, with a range of approximately -200°C to +350°C.
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Type E: Chromel-Constantan thermocouples. Type E thermocouples are suitable for moderate temperatures and have a range of approximately -200°C to +900°C.
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Type N: Nicrosil-Nisil thermocouples. Type N offers improved performance and stability over Type K at high temperatures, with a range of approximately -200°C to +1300°C.
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Type S, Type R, Type B: Noble metal thermocouples. These types, made of platinum and platinum-rhodium alloys, are used for high-temperature applications. Type S covers a range of approximately 0°C to +1600°C, Type R covers approximately 0°C to +1600°C, and Type B covers approximately 600°C to +1700°C.
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Type C: Tungsten-Rhenium thermocouples. Type C thermocouples are suitable for ultra-high-temperature applications, with a range of approximately 0°C to +2320°C.
These are the most common types of thermocouples, but there are other specialized types available for specific applications as well. The selection of the appropriate type depends on factors such as temperature range, accuracy requirements, environmental conditions, and budget constraints.
