What is Electricity?

The Flow of Charge

Electricity is the flow of electric charge through a conductor. At the atomic level, this charge is carried by electrons — tiny negatively charged particles orbiting the nucleus of an atom.

Electric Charge

All matter is made of atoms, which contain protons (positive charge), neutrons (no charge), and electrons (negative charge). When electrons are freed from their atoms, they can flow through materials — this flow is what we call electric current. The unit of electric charge is the Coulomb (C). One Coulomb equals approximately 6.24 × 10¹⁸ electrons.

Conductors vs Insulators

Materials can be classified by how easily they allow electric current to flow through them:

• •Conductors: Materials with free electrons that allow easy current flow. Examples: copper, aluminum, gold, silver.
• •Insulators: Materials that resist electron flow. Examples: rubber, glass, plastic, ceramic.
• •Semiconductors: Materials that can act as either conductors or insulators depending on conditions. Examples: silicon, germanium. These are the basis of modern electronics.

Conventional Current vs Electron Flow

There are two ways to describe current direction. Conventional current flows from positive (+) to negative (−), which was the original convention established by Benjamin Franklin before electrons were discovered. Electron flow is the actual physical movement of electrons, from negative to positive. In circuit analysis, we almost always use conventional current.