Electrical current is defined as the flow of what?

Electrical current is defined as the flow of electrons. In conductive materials, particularly metals, atoms have freely moving electrons that can carry charge from one point to another when a potential difference (voltage) is applied. This movement of electrons constitutes the electric current.

Contrary to this, protons and neutrons, which are found within the atomic nucleus, do not move freely in conductors to create current. Photons, being particles of light, also do not contribute to the flow of electric charge in a conductor. Thus, focusing on the behavior of electrons is crucial for understanding how electrical current works in circuits and electrical systems.