What is an RTD and how does it work?

RTD (Resistance Temperature Detector) measures temperature based on the principle that electrical resistance of metals changes with temperature. Platinum is commonly used (Pt100 has 100 ohms at 0 degrees C) due to its stability and linear response. RTDs offer high accuracy (0.1 degree C), excellent repeatability, and wide range (-200 to 850 degrees C), making them preferred for precision temperature measurement in process industries.