Electrical Engineering ⇒ Topic : Variation of Resistivity With Temperature

Variation of Resistivity With Temperature

Not only resistance but resistivity or specific resistance of a material also changes with temperature. The change in resistivity per °C change in temperature is called temperature coefficient of resistivity. In case of metals, the resistivity increases with increase in temperature and vice-versa. It is found that resistivity of a metallic conductor increases linearly over a wide range of temperatures and is given by

Note that temperature coefficient of resistivity is equal to temperature coefficient of resistance α₀

VARIATION OF RESISTIVITY WITH TEMPERATURE

The resistivity of a metallic conductor decreases with decrease of temperature. It increases with increase of temperature. It has been found that the change of resistivity is proportional to the change in temperature over the normal operating range of temperature. Mathematically

where α_o is the temperature co-efficient of resistance at 0°C, ρ_o is resistivity at 0°C, ρ_t is resistivity at t°C, and t is the change of temperature.