Resistors become insulators at some high temp.

[anonymoussome]

Every conductor or insulator becomes/is believed to become perfectly conducting at o kelvin

Similarly every resistor should also have some upper limit i.e. it should become insulator at some very high temperature?
Is it so?
Please explain...

 

[ZapperZ]

Every conductor or insulator becomes/is believed to become perfectly conducting at o kelvin

No they don't! A semiconductor becomes more insulating as the temperature becomes lower. So your starting premise here is already false. This is one of the properties of a typical insulating material.

Zz.

 

[stewartcs]

No they don't! A semiconductor becomes more insulating as the temperature becomes lower. So your starting premise here is already false. This is one of the properties of a typical insulating material.

Zz.

Although this is true of semiconductors, I believe the OP was referring to metallic conductors, not semiconductors. In a metallic conductor, the electrical resistance tends to zero as the temperature tends to absolute zero.

Conversely, the electrical resistance will typically increase in a conductor as the temperature increases.

$$R = \frac{L}{A} \cdot \rho_0( \alpha(T - T_0) + 1)$$

http://hyperphysics.phy-astr.gsu.edu/hbase/solids/scond.html#c1

http://en.wikipedia.org/wiki/Ohm's_law

CS

 

[f95toli]

Although this is true of semiconductors, I believe the OP was referring to metallic conductors, not semiconductors. In a metallic conductor, the electrical resistance tends to zero as the temperature tends to absolute zero.

But even that is only true for idealized conductors. In real metals the conductivity will saturate at relatively high temperatures, often tens of K. The reason is simply that it is only the phonon scattering that depends on the temperature, at low temperatures scattering against impurities, grain boundaries etc will start to dominate and these processes are essentially temperature independent and sets a limit for the conductivity.

 

[stewartcs]

But even that is only true for idealized conductors. In real metals the conductivity will saturate at relatively high temperatures, often tens of K. The reason is simply that it is only the phonon scattering that depends on the temperature, at low temperatures scattering against impurities, grain boundaries etc will start to dominate and these processes are essentially temperature independent and sets a limit for the conductivity.

I know, that's why I said tends to zero and not is zero.

CS

 

[ZapperZ]

Although this is true of semiconductors, I believe the OP was referring to metallic conductors, not semiconductors. In a metallic conductor, the electrical resistance tends to zero as the temperature tends to absolute zero.

Conversely, the electrical resistance will typically increase in a conductor as the temperature increases.

$$R = \frac{L}{A} \cdot \rho_0( \alpha(T - T_0) + 1)$$

http://hyperphysics.phy-astr.gsu.edu/hbase/solids/scond.html#c1

http://en.wikipedia.org/wiki/Ohm's_law

CS

I'm not sure how this is relevant to what I said. Note the OP:

Every conductor or insulator becomes/is believed to become perfectly conducting at o kelvin

I wasn't addressing conductors. I was addressing insulators/semiconductors. That's why I said that whole premise is false. Insulators do not behave the same way as metals as far as temperature dependence goes.

BTW, I'm a condensed matter physicist, just so you know that I'm well aware of "Ohm's law" and temperature dependence of resistivity.

Zz.

 

[stewartcs]

I'm not sure how this is relevant to what I said. Note the OP:

I wasn't addressing conductors. I was addressing insulators/semiconductors. That's why I said that whole premise is false. Insulators do not behave the same way as metals as far as temperature dependence goes.

BTW, I'm a condensed matter physicist, just so you know that I'm well aware of "Ohm's law" and temperature dependence of resistivity.

Zz.

True, but I was merely point out to the OP, not to you of course, that there is indeed a relationship between temperature and resistivity amongst conductors as it seemed to be part of the inquiry.

CS