RTD (resistance Temperature Detector)

What is the difference between and a resistance temperature detector (RTD) and a thermocouple? Both RTDs and thermocouples are sensors used to measure heat in scales such as Fahrenheit and Kelvin. Such devices are used in a broad range of applications and settings, often presenting people with the dilemma of choosing to use either RTDs or thermocouples. Each kind of temperature sensor has its own advantages and disadvantages that make it suitable for certain conditions and circumstances.