Answer: Standard resistance coils are made from alloys, which have a high resistivity value and a low temperature coefficient of resistivity.
The temperature coefficient of resistivity of a conventional resistance coil should be quite modest. That means, the resistance of certain materials will not change much when the temperature changes.
We also know that if a material’s resistivity is high, its resistance increases. As a result, high resistivity materials should be used to make a resistance coil for greater standard resistance.
Alloys like constantan and manganin are examples of materials with a high resistivity value, a modest temperature coefficient, and are largely unaffected by environmental influences such as temperature, moisture, and air. As a result, alloys are employed in the production of conventional resistance coils.