Temperature coefficient of resistance

About the effect of superconductivity know, probably, everything. In any case, we heard about him. The essence of this effect is that at minus 273 ° C the resistance of the conductor to the flowing current disappears. Already one of this example is enough to understand that there is its dependence on temperature. And this dependence describes a special parameter - the temperature coefficient of resistance.

Any conductor prevents current flowing through it. This counteraction for each conductive material is different, it is determined by many factors inherent in a particular material, but it will not be a question later on. Interest at the moment is its dependence on temperature and the nature of this relationship.

Conductors of electrical current usually are metals, they have a resistance with increasing temperature, and when it decreases, it decreases. The magnitude of this change, occurring at 1 ° C, is called the temperature coefficient of resistance, or abbreviated to TCS.

The value of TCS can be positive and negative. If it is positive, then as the temperature increases, the resistance of the conductor increases, if negative, it decreases. For most metals, used as conductors of electric current, TCS is positive. One of the best conductors is copper, the temperature coefficient of copper resistance is not that best, but compared to other conductors, it is smaller. You just need to remember that the value of the TCS determines how the resistance value will change when the environmental parameters change. Its change will be more significant than this coefficient is greater.

Such a temperature dependence of the resistance should be taken into account when designing radioelectronic equipment. The matter is that the equipment should work under any environmental conditions, the same cars are operated from minus 40 ° С to plus 80 ° С. And there are a lot of electronics in the car, and if you do not take into account the influence of the environment on the operation of the circuit elements, you can face the situation when the electronic unit works fine under normal conditions, but refuses to work under the influence of a low or high temperature.

This dependence on the conditions of the environment and take into account the developers of the equipment when designing it, using the temperature coefficient of resistance for calculating the parameters of the circuit. There are tables with data of TCS for the materials used and calculation formulas for which, knowing the TCR, it is possible to determine the resistance value under any conditions and to take into account the possible changes in the operation modes of the circuit. But to understand what TCS is, now no formulas or tables are needed.

It should be noted that there are metals with a very small value of TCS, and they are used in the manufacture of resistors, the parameters of which depend little on the changes in the environment.

The temperature coefficient of resistance can be used not only to take into account the influence of fluctuations in environmental parameters, but also to measure temperature. For what it is enough to measure the resistance. Knowing the material that has been exposed, it is possible to determine from the tables which temperature corresponds to the measured resistance. As such a meter can be used ordinary copper wire, however, it is necessary to use it a lot and rewind in the form, for example, of a coil.

All of the above does not cover completely all the issues of using the temperature coefficient of resistance. There are very interesting possibilities of application associated with this coefficient in semiconductors, in electrolytes, but what is presented is sufficient for understanding the concept of TCR.