RTD Vs Thermocouple
Thermocouples
A thermocouple uses two metal wires to produce a voltage relative to the temperature present in the junction between them. There are many specialised kinds of thermocouples – they can combine different metals to measure various characteristics and temperature ranges, and produce specialised calibrations.
Resistance temperature detectors (RTDs)
An RTD sensor measures temperature based on the resistance changes in a metal resistor inside. The most popular RTDs, called PT100 sensors, use platinum and have a resistance of 100 ohms at 0°C.