Conductors and their increase of resistance with temperature

In summary, conductors have a positive temperature coefficient of resistance, while insulators and semiconductors have a negative temperature coefficient of resistance. This is because in both conductors and semiconductors, conduction is due to free electrons colliding with each other during their motion. However, in semiconductors, the increase in temperature leads to an increase in the number of charge carriers, resulting in higher conductivity. This is due to the smaller band gap between the valence band and conduction band, allowing for more electrons to move into the conduction band at higher temperatures. Therefore, in semiconductors, the resistance decreases with an increase in temperature.
  • #1
logearav
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Revered members,
Conductors have positive temperature coefficient of resistance, that is , their resistance increases with temperature. While for insulators and semi conductors, the resistance decreases with increase in temperature, what we call negative temperature coefficient of resistance.
In both semiconductors and conductors, conduction is due to free electrons. The free electrons collide with each other during their motion. Increase of Temperature is a factor for generation of free electrons.
But, why resistance increases in conductors while decreases in semiconductors with increase of temperature? After all, in both the cases collisions between free electrons happen.
 
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  • #2
logearav said:
Revered members,
Conductors have positive temperature coefficient of resistance, that is , their resistance increases with temperature. While for insulators and semi conductors, the resistance decreases with increase in temperature, what we call negative temperature coefficient of resistance.
In both semiconductors and conductors, conduction is due to free electrons. The free electrons collide with each other during their motion. Increase of Temperature is a factor for generation of free electrons.
But, why resistance increases in conductors while decreases in semiconductors with increase of temperature? After all, in both the cases collisions between free electrons happen.

But the conductivity isn't just a function of scattering. If the number of charge carrier increases with increasing temperature, then that could contribute to an increase in conductivity as well.

This is what occurs in a semiconductor. Since the band gap between the valence band and the conduction band is small enough, increasing the temperature increases the likelihood that an electron from the valence band can gain enough energy to go into the conduction band. Thus, as higher temperatures, there will be more charge careers, not only as electrons in the conduction band, but also holes in the valence band. More charge carriers, higher conductivity.

Zz.
 

Related to Conductors and their increase of resistance with temperature

1. What is a conductor?

A conductor is a material that allows electric current to flow through it easily. It typically has low resistance and is often used in electrical circuits.

2. How does temperature affect the resistance of a conductor?

As the temperature of a conductor increases, its resistance also increases. This is due to the fact that as the temperature rises, the atoms in the conductor vibrate more, causing more collisions with the electrons and hindering the flow of current.

3. Why do some conductors have a higher increase in resistance with temperature than others?

The increase in resistance with temperature depends on the material's properties, such as its atomic structure and the type of bonding between atoms. Generally, materials with stronger bonds and a more organized atomic structure will have a lower increase in resistance with temperature.

4. Is there a limit to how much a conductor's resistance can increase with temperature?

Yes, there is a limit known as the Curie temperature. This is the temperature at which the material's atoms become too energetic and begin to lose their alignment, causing a sudden increase in resistance. Above this temperature, the material can no longer be considered a conductor.

5. Can temperature affect the performance of electrical devices that use conductors?

Yes, temperature can greatly impact the performance of electrical devices that use conductors. For example, in electronic circuits, an increase in temperature can cause a decrease in the flow of current, leading to reduced efficiency and potential overheating. This is why proper temperature management is crucial in the design and use of electronic devices.

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