Temperature Dependence of Resistivity

The resistivity of the metallic conductors is found to increase with temperature. Over a limited range of temperature, the resistivity of metallic conductors is found to increase linearly (i.e., approximately) with temperature.


Thus, the temperature coefficient of resistivity may be defined as fractional change in resistivity per unit rise in temperature.

Above graph shows that variation of resistivity of a ohmic conductor with temperature(in kelvin)
Some important details about temperature dependence of resistivity as follows
a) For certain metals at lower temperature, the temperature dependence of resistivity is quite non-linear. The graph will be curve.
b)Metallic alloys like Nichrome have high resistivity. Therefore, it is used widely in electric heaters.
c)Resistivity of manganin and constantan is nearly independent of temperature. So, manganin is widely used in making resistance boxes, standard resistances and wires used in metre bridge and potentiometer.
d) The resistivity of carbon decreases with increase of temperature and has a negative temperature coefficient of resistance. Semiconductors like germanium and silicon, also behave in the same way.