Question

What is the thermocouple and Seebeck effect?

Answer 1

### Thermocouple

A **thermocouple** is a device used to measure temperature. It consists of two different metals or alloys joined at one end, creating a junction. When the junction is heated or cooled, it generates a small voltage (called the **thermoelectric voltage**), which can be measured and used to determine the temperature at that junction.

The two metals in a thermocouple are usually chosen for their different electrical properties, so when they are heated or cooled, the difference in temperature between the junction and the other ends of the wires generates a measurable voltage.

### Seebeck Effect

The **Seebeck effect** is the phenomenon that causes a thermocouple to generate voltage when there is a temperature difference between the two ends of the wires. Named after physicist **Thomas Seebeck**, this effect occurs because the electrons in the different metals move at different rates when they are heated. This creates a voltage difference between the two ends of the wires, and this voltage is proportional to the temperature difference.

In simple terms, when one end of a thermocouple is heated (or cooled), a voltage is produced due to the difference in temperatures between the hot and cold junctions. This voltage can then be used to measure the temperature at the hot junction.

### Example:

If you have a thermocouple with one end placed in a hot environment (say, 100°C) and the other end in a colder environment (say, 20°C), the temperature difference between the two junctions causes a voltage to develop. By measuring this voltage, you can calculate the temperature of the hot junction.

### Summary:

- **Thermocouple**: A device made of two different metals joined together, used to measure temperature.
- **Seebeck Effect**: The creation of a voltage when there is a temperature difference between two different metals.