RTD (Resistance Temperature Detector) and thermocouple are two different types of temperature sensors.
An RTD (Resistance Temperature Detector) measures temperature by measuring the resistance of a material that changes with temperature. They are commonly made of Platinum, Copper or Nickel, and are accurate over a wide temperature range. RTDs are commonly used in industrial and laboratory settings. They can be used to measure temperature in a wide range, from -200 to 850 °C. They are more accurate than thermocouples but also more expensive.
A thermocouple is a type of temperature sensor that uses the thermoelectric effect to measure temperature. They consist of two wires made from different metals, which when heated or cooled, will produce a voltage proportional to the temperature difference. They are commonly used in industrial and medical applications. They are cheaper than RTDs but not as accurate, with a measurement range from -200 to 2300 °C.
Both RTD and thermocouple have their own unique set of features and capabilities, and the choice of which one to use will depend on the specific requirements of the application, including measurement range, accuracy, durability, cost, and environmental conditions.