Question

what is the effect of temperature on the resistance of alloys?

Answer 1

The temperature coefficient of resistance ($\alpha$) represents the resistance change factor per degree of temperature change. When temperature coefficient of resistance ($\alpha$) is a positive number (in metals), resistance increases with increasing temperature. When temperature coefficient of resistance ($\alpha$) is a negative number (in semiconductors), resistance decreases with decreasing temperature. In case of some alloys, such as nichrome, manganin, constantan, etc., though ​temperature coefficient of resistance ($\alpha$) is a positive but its value is extremely small, close to zero. It means resistance hardly changes with changing temperature. In other words, resistance of some alloys are nearly independent of temperature.