Thermocouples are created when two different metals are joined together at a junction. Connecting the other ends of these dissimilar metals at another junction establishes an electrical circuit.
- Temperature Sensitivity: A current will flow in the circuit if the temperatures at the two junctions differ.
- Electromotive Force (EMF) Differences: The current generated is due to the variance in electromotive force (EMF) created at the two junctions resulting from the temperature difference between them.
- Voltage Measurement: The voltage difference between the two junctions is measured, and this difference is directly proportional to the temperature disparity between them.
- Temperature Differences: It’s important to note that thermocouples are specifically designed to measure temperature differences.
Effects Associated with Thermocouples
- The Seebeck Effect:
This effect indicates that the voltage generated in a thermocouple is directly proportional to the temperature difference between its two junctions. - The Peltier Effect:
It describes that when a current passes through a thermocouple, one junction gets heated (releasing energy) while the other junction is cooled (absorbing energy). - The Thompson Effect:
When a current flows through a conductor experiencing a temperature difference, heat can be either generated or absorbed, based on the current’s direction and the temperature variation.
