Different electrical temperature sensors:
1. RTD
2. Thermistors
3. Thermocouples
Thermocouple:
Explanation:
If two dissimilar metals are joined together so as to form a closed circuit, there will be two junctions where they meet each other. Inorder to prevent the formation of a second junction, the wires of thermocouple are insulated from each other by being threaded through porcelain insulators. Lead wires connect the measuring junction of the thermocouple to the indicating instrument. If one of these junctions is heated, then, a current flows in the circuit which can be detected by a galvanometer. The amount of the current produced depends on the difference in temperature between the two junctions and on the characteristics of the two metals.