Another caveat: In a metal, stationary atoms share a sea of mobile electrons.

Current then flows between source and drain in a surface channel maintained by the gate voltage, which controls the concentration of mobile electrons.

When a magnetic field is applied, each mobile electron is forced to spiral about the field's direction, although its energy is not changed.

Resistance comes from mobile electrons losing momentum in scattering and is usually inevitable except in superconductivity.

Rather there is a "sea" of mobile electrons that are free to move in response to an electric voltage.

It is based on the Drude model of mobile electrons.

Certain impurities in graphite actually donate more mobile electrons, which sometimes make it lighter still.

In a metal, each metal atom contributes about one mobile electron that helps the current flow.

The breakdown process forms a plasma that contains enough mobile electrons and positive ions to make it an electrical conductor.

To allow conduction, semiconductors are doped with impurities which donate mobile electrons (or holes).