The PT 100 Resistance Temperature sensor measures the resistance of a platinum element. The resistance is then converted to temperature.
The vibrating wire Temperature sensor comprises a stainless steel body which houses a vibrating wire sensing unit/ transducer. As the body expands or contracts due to temperature, this changes the tension in the vibrating wire. The resulting frequency is converted to output temperature.
The Thermocouple Temperature sensor comprises two dissimilar conductore jointed at one end to form a hot junction. This junction produces a voltage so as the junction is headed or cooled, the voltage change and is converted to return the temperature.