. Resistance temperature detectors (RTDs) are temperature sensors that contain a resistor that changes resistance value as its temperature changes, basically a kind of thermistor. In this sensor, the resistor is actually a small strip of Platinum with a resistance of 100 ohms at 0°C, , the PT type of RTD is much most stable and precise (but also more expensive) PT100's have been used for many years to measure temperature in laboratory and industrial processes,

 PT100 sensor is equipped with an stainless steel shield that is good from -50°C to 320°C.

PT100 features:

• Based on resistance measurement principles
• Resistor material is Platinum with a value of 100 ohm at temperature 0°C
• Resistance variation is a function of temperature: 0.385Ω/°C nominal

Each sensor comes with three wires. Two of the wires connect to either side of the platinum resistor like you'd expect. The third wire is also connected to one end of the PT100. If your RTD amplifier supports 3-wire sensors, it will drive the resistor with the first two wires, and measure the voltage differences so that it can subtract any voltage drop from the wires. If your RTD amplifier only has 2-wire support simply leave the third wire disconnected.