Temperature Coefficient of Resistance

Temperature Coefficient of Resistance:

The reason behind the temperature coefficient of resistance in a conductor may submit intuitive reasons.

The resistance of a material having to rely on a number of phenomena. One of them is the number of collisions that take place between the loads and atoms in the material. No. of collisions increases as the temperature increases. It can be seen that there is a marginal increase in the resistance against temperature.

It will not always be the case because some of the material has a negative temperature coefficient of resistance. This may be caused by the fact that release additional charge carriers with increasing temperature which lead to a reduction of the resistance with the temperature. As expected, this effect is often seen in the semiconductor materials.

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If we take the temperature dependence resistance is generally assumed that the temperature coefficient of resistance was followed by a linear law. This is the case around room temperature, and metals and many other materials. It was discovered that the effect as a result of the number of collisions is not always consistent, especially at low temperatures for these materials.

Resistance is inversely proportional to the mean free path between collisions. It results in the increase of the resistivity / resistance with increasing temperature. At temperatures above about 15 ° K (so above absolute zero) is limited by the atoms thermal vibrations and this gives the linear region with which we are familiar. Below this temperature, the resistance.

Temperature Coefficient of Resistance Formula:

The resistance of a conductor at a given temperature can be calculated. The temperature coefficient of the resistance, the resistance to a standard temperature and the working temperature . The equation for the resistance temperature dependence can

F

Where     R = the resistance at temperature T

R0 = the resistance at temperature Tref

α = the temperature coefficient of resistance for the material

T = the material temperature in °Celcius

Tref = is the reference temperature

The temperature coefficient of resistance is normally standardized in relation to a temperature of 20°C.

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Where     R20 = the resistance at 20°C     α20 is the temperature coefficient of resistance at 20°C

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Posted by on Jul 16 2016. Filed under Latest Updates, ELECTRICAL & ELECTRONICS, Temperature & Heat. You can follow any responses to this entry through the RSS 2.0. You can leave a response or trackback to this entry

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