Ohmic conductors: Those electrical conductors which obey ohm’s law are ohmic conductors. The resistance of ohmic conductor doesn’t change as per voltage. When we plot the graph between V and I, the graph is straight line passing through the origin. Metallic conductors like copper, iron, zinc etc are some of the examples of ohmic conductors.
Non-ohmic conductors: Those electrical conductors which does not obey ohm’s law are ohmic conductors. The resistance of ohmic conductor changes as per voltage. When we plot the graph between V and I is straight line and a curve. Semiconductor like silicon, germanium are the examples of non-ohmic conductors.
Perfect conductor: The electrical conductor with zero resistivity is called perfect conductor. Perfect conductor is an ideal concept as there is always loss of some amount of current in different forms like heat, resistivity etc.
Superconductors: Those electrical conductors which have zero electrical resistance is called superconductors. When a conductor is cooled at very low temperature, it loses all of its electrical resistivity and acts as a superconductor. Some metals like nitrogen, copper can show this property.