Probably everyone knows about the effect of superconductivity . In any case, they heard about him. The essence of this effect is that at minus 273 ° the resistance of the conductor to the flowing current disappears. This example alone is enough to understand that its temperature dependence exists. And this dependence is described by a special parameter - the temperature coefficient of resistance.
Any conductor impedes the flow of current through it. This opposition is different for each conductive material, it is determined by many factors inherent in a particular material, but we will not discuss this further. Of interest at the moment is its dependence on temperature and the nature of this dependence.
Metals are usually conductors of electric current; their resistance increases with increasing temperature, and decreases with decreasing temperature. The magnitude of this change per 1 ° C is called the temperature coefficient of resistance, or TCS for short.
The value of TCS can be positive and negative. If it is positive, then with increasing temperature the resistance of the conductor increases, if it is negative, it decreases. For most metals used as electric current conductors, TCS is positive. One of the best conductors is copper, the temperature coefficient of resistance of copper is not so much the best, but compared with other conductors, it is less. You just need to remember that the value of the TCS determines what resistance will be when the environmental parameters change. Its change will be the more significant the greater this coefficient.
Such a temperature dependence of the resistance should be taken into account when designing electronic equipment. The fact is that the equipment should work under any environmental conditions, the same cars are operated from minus 40 ° to plus 80 ° . But 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 circuit elements, you may encounter a situation where the electronic unit works fine under normal conditions, but refuses to work when exposed to low or high temperatures.
It is this dependence on environmental conditions that the developers of the equipment take into account when designing it, using the temperature coefficient of resistance for calculating the parameters of the circuit. There are tables with TCS data for the materials used and calculation formulas, by which, knowing the TCS, you can determine the resistance value in any conditions and take into account possible changes in the circuit operating modes. But to understand what TCS is, now neither formulas nor 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 on environmental changes weakly.
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. Why just measure the resistance. Knowing the material that has been exposed, the tables can determine what temperature corresponds to the measured resistance. An ordinary copper wire can be used as such a meter, however, it will have to be used a lot and wound in the form of, for example, a coil.
All of the above does not fully cover all issues of using the temperature coefficient of resistance. There are very interesting applications associated with this coefficient in semiconductors, in electrolytes, but what is stated is enough to understand the concept of TCS.