HVAC Star Practice Exam 2026 – The Complete All-in-One Resource for Exam Success!

Electric current is the flow of electric charges. In a typical conductor like a metal wire, the carriers are electrons. The atoms form a fixed lattice, but the outer electrons are free to move when a potential is applied, so their drift constitutes the current. Protons are bound in the nucleus and don’t move in solids, and neutrons carry no charge, so they don’t contribute to current. Ions can carry current in solutions or plasmas, but in ordinary metal conductors the moving particles are electrons. That’s why electricity is explained by the movement of electrons.