What is the difference between an RTD and a Thermocouple?

Question

Accepted Answer

RTDs and thermocouples are temperature sensors with different principles, accuracy, and applications in various fields.

Principle of Operation: RTDs (Resistance Temperature Detectors) measure temperature by correlating the resistance of the sensor with temperature, while thermocouples generate a voltage based on the temperature difference between two junctions of different metals.
Accuracy: RTDs are generally more accurate and stable over time compared to thermocouples, which can have a wider margin of error.
Temperature Range: Thermocouples can measure a wider range of temperatures (up to 2000°C) compared to RTDs, which are typically limited to around 850°C.
Response Time: Thermocouples have a faster response time due to their smaller size and lower thermal mass, making them suitable for dynamic measurements.
Applications: RTDs are often used in laboratory and industrial applications requiring precision, while thermocouples are commonly used in high-temperature environments like furnaces and engines.

Accepted Answer

RTD temp.range 200-400c, T/C temp.range 200-1750c

Accuracy: 0.1 to 1C, 0.5 to 5C.

Principle: Change in resistance with respect to temp., See Back effect.

Type: PT100, PT50, PT100. E,J,K,S,N,T.

Responce time: 1 to 50 sec, 0.1 to 10 sec.

Cost: More than T/C, Less than RTD.

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