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# Seebeck Effect

## What is Seebeck Effect?

Last updated date: 23rd Mar 2023
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The Seebeck effect is a major observation in the study of physics. It is widely used in the application of semiconductors and conductors, and thus, has a lot of practical applications for us in our daily lives. German physicist Thomas Jonahan Seebeck was the one who formulated this, when he noticed that a magnetic compass, when brought in close proximity of two semiconductors can undergo a variation.

In short, the Seebeck effect explains the relationship between changes in temperature and semiconductors.

### What Is The Seebeck Effect?

In 1821, German physicist Thomas Seebeck had observed the properties of the thermoelectric effect. It was seen that a circuit that had two different metals developed an EMF when their junctures were maintained at different temperature levels. These non-similar metals form what is known as a thermocouple, and the current that passes through this circuit is known as thermoelectric current.

The Seebeck effect explained the production of an electromotive force and the electric current in a loop of materials consisting of at least two dissimilar conductors maintained at two different temperatures, known as the thermocouples. It can be termed as the Seebeck effect thermocouple.

The Seebeck effect is a reversible process. If the hot and cold junctions are interchanged then the direction of the current will also change. Therefore, the thermoelectric effect is a reversible process. The magnitude and sign of thermo EMF depend on the materials of the two conductors and the temperature of the hot and cold junction.

Seebeck after discovering thermal properties of different pairs of metals arranged in series is called thermoelectric series. The thermoelectric effect is the conversion of temperature differences into electrical potential differences or vice versa using a thermocouple.

The Seebeck effect is the best example of an electromotive force. Through the Seebeck effect, we can also calculate the measurable electric currents or voltages in the same way as electromotive forces.

The local current density can be calculated using the formula,

⇒ J = σ(-ΔV + $E_{emf}$)

Where, ΔV - The potential difference developed

$E_{emf}$ - Electromotive force

σ - The local conductivity

The electromotive force created will explain the Seebeck effect and the equation of electromotive force in terms of the Seebeck coefficient is given by,

⇒  $E_{emf}$ = -SΔT

Where, S - The Seebeck coefficient

The Seebeck coefficient implies that a certain potential is induced in the circuit per change in temperature. It should be remembered that the Seebeck coefficients can change with temperature and they are dependent on the composition of the conductor. Usually it has been noticed that at room temperature, the Seebeck coefficient ranges between -100V/K to 1000V/K.

### What Are Some Applications Of the Seebeck Effect?

Due to the fact that this monitors the change in temperature with conductivity, it is very useful in a number of modern operations that require electricity and conductivity at differential temperatures. Some of the common applications of this property are:

• It can be useful in thermoelectric generators, which are used in industries and power plants to not let residual heat go waste and harness that into electricity.

• In the automobile industry as well, the Seebeck effect can have many applications. It can be used to employ a thermoelectric generator which will lead to less fuel wastage.

• It is also useful in thermocouples which can measure the potential difference between two semiconductors. Thermophiles are thermocouples arranged in series, and the Seebeck effect can be seen there as well.

## FAQs on Seebeck Effect

1. Define Seebeck Effect or the Seebeck Principle?

The Seebeck effect definition can be stated as it explains the production of an electromotive force and the electric current in a loop of materials consisting of at least two dissimilar conductors maintained at two different temperatures known as the thermocouples.

2. What are Thermocouples?

A thermocouple is an electrical device made of two dissimilar metals or conductors placed at two different temperatures.

3. What is a Seebeck generator?

When two non-similar conductors are connected to a source of heat and then that is transformed to voltage to keep up with the supply of the load, the arrangement is called a Seebeck generator. In small levels, this can work independently of any external source of electrical power to fuel the system. The movement of heat from the different ends leads to the formation of a temperature gradient and this results in a very uniform source of power. This is because the voltage formed as a result becomes the main source to power the system.

4. Is the Seebeck effect a possible alternative to clean energy?

Since the Seebeck generator has the ability to power itself without any external source of power, it has been widely viewed as a self-sufficient and greener source of energy. However, in order to work on a large scale that is enough to power a house or a city, there needs to be better results. Newer methods are being tried out, one of them being the spin Seebeck effect, which can basically be used to perform the same task but with much greater efficiency than the traditional model.

5. What is the principle of a thermocouple?

A thermocouple works based on the principle of the Seebeck effect. This is an electrical device that is made up of two different metals that are placed at two different temperatures, and this can lead to the formation of a Seebeck generator, which can power itself on a small scale. The closed-circuit nature of this will lead to the inducement of electromotive force in the circuit, which will power the system. This can be seen in action in a number of heavy industries.

6. What is the difference between Seebeck and Peltier's effects?

The Peltier effect describes the exact opposite of what the Seebeck effect points to. The Seebeck effect is concerned with the creation of electricity when there is a temperature gradient between two non-similar semiconductors. The Peltier effect, on the other hand, talks about the creation of temperature change with changes in electric voltage. There is a voltage gradient applied at the ends of the system, which leads to a consequent change in temperature of the system, and this is all the Peltier effect describes.

7. Is the Seebeck effect able to be subject to change?

Yes, the Seebeck effect is not irreversible in any way. Once it has been started, it can also be stopped, the temperature at the ends can be changed, any number of variables can be moved as long as the basic principle remains intact. Suppose the warm and the cold points are changed in the system, then the flow of the voltage will also be changed for obvious reasons. This will reverse the process in the other way, but will not make it stop completely.