An electrical conductor is an object or type of material that allows the flow of charge (electrical current), with the application of voltage, in one or more directions.
The conductive materials are characterized by the presence of free electrons in the valence band of the crystal lattice atoms (conductors of the first species) or contain ionic species that take charge of carrying the current (conductors of the second species). The electrical conductivity of a first species conductor can be interpreted using the band model. The net charge on a conductor is distributed over its surface, since in this way the individual charges (which repel each other) maximize their mutual distance reaching a configuration that minimizes energy.
Conduction materials include metals, electrolytes, superconductors, semiconductors, plasmas and some nonmetallic conductors such as graphite and conductive polymers. The metallic materials (metals and their alloys) are typically good conductors; the best in descending order are:
On the other hand, electricity can also easily conduct:
- water (only if not pure);
- earth (ground);
- human body.