Temperature Coefficient of Resistance

Temperature Coefficient of Resistance General Aim

The purpose of temperature coefficient of resistance:

1. To investigate the change in the resistance of a sample as the temperature of the sample is varied.
2. Determine the temperature coefficient of resistance.

Temperature Coefficient of Resistance Method

In this experiment, we determine the temperature coefficient of resistance of some samples. This is done by measuring the resistance of the sample in different temperatures. From a graph of the resistance against temperature, the temperature coefficient of resistivity of a sample is determined.

Theoretical Background Temperature Coefficient of Resistance

• The statistical distribution of the electrons was first determined by Enrico Fermi and Paul Dirac in 1926 and is known as the Fermi-Dirac distribution.
• At temperatures of more than a few Kelvin, the mobility of electrons, and hence the conductivity, decreases linearly with temperature. Thus, the resistivity​ and therefore resistance of a metal increases linearly with temperature.
• The relation between the temperature of material and its resistance is called temperature coefficient of material, which is often expressed in practical applications as the resistor temperature coefficient.

Principle Of Work

• In this experiment, you will determine the resistance of a sample while its temperature is varied from 300C to 900C in steps 50C.
• The resistance is measured using an ohmmeter and the temperature measured using a thermometer.
• You should make a graph of the resistance versus temperature and determine the temperature coefficient of resistance from the slope of the obtained graph.