The basic principle of thermocouple temperature measurement is based on the Seebeck effect. This phenomenon occurs when two different conductive materials are joined at two junctions, creating a circuit. When the junctions are at different temperatures, a voltage is generated that is proportional to the temperature difference between them.

Here’s a simplified breakdown:

1. Two Metals: A thermocouple consists of two different metals (e.g., copper and constantan) joined at one end.

2. Temperature Difference: When one junction (hot junction) is heated while the other (cold junction) is kept at a known reference temperature, a voltage is produced.

3. Voltage Measurement: This voltage can be measured and converted into a temperature reading using established calibration curves.

The resulting voltage is typically in the millivolt range and varies depending on the materials used and the temperature difference, allowing for accurate temperature measurement across a wide range of applications.