Electric Current, Charge Flow, and Voltage Fundamentals

Atom

The basic building block of matter, composed of a positively charged central nucleus surrounded by negatively charged electrons.

Free Electrons

Electrons in certain materials that are loosely bound to the nucleus and can easily detach and move.

Conductor

A material (such as copper wire) that contains free electrons, allowing electric charge to flow through it.

Electric Current

The rate of flow of electric charges through a conductor over time.

Current Formula

$I = \frac{q}{t}$, where $I$ represents electric current, $q$ is the charge, and $t$ is the time taken.

Conventional Current

The flow of positive charges, defined as moving from positive potential to negative potential.

Electronic Current

The actual physical flow of negative charges (electrons), moving from negative potential to positive potential.

Ampere ($\text{A}$)

The SI unit of electric current, equivalent to one coulomb of charge passing a point in one second ($1\,\text{A} = 1\,\text{C/s}$).

Coulomb ($\text{C}$)

The standard unit of electric charge, equal to the combined charge of $6 \times 10^{18}$ electrons.

Ammeter

An electrical instrument used to measure the rate of electric current flowing through a circuit.

Voltage

The difference in electric potential between two points that acts as an electric push driving charges through a circuit.