Particles Velocity Calculator

What Is Particle Drift Velocity?

In a conductor, charge carriers move slowly on average even when current is large. Drift velocity is the average speed of those carriers along the wire direction. It links macroscopic current to microscopic carrier motion.

Drift Velocity Formula

Here $I$ is current in amperes, $n$ is carrier number density in m$^{-3}$, $q$ is charge per carrier in coulombs, and $A$ is cross-sectional area in m$^2$. For electrons in copper, $q$ is approximately $1.602 \times 10^{-19}$ C.

Why Drift Velocity Is Small

Copper has an enormous carrier density near $8.5 \times 10^{28}$ m$^{-3}$. Even at several amperes through a thin wire, the average drift speed is typically less than 1 mm/s. Individual electrons move much faster between collisions, but their net drift is tiny.

Related tools: Drift Velocity Calculator, Electrical Mobility Calculator, and Current Divider Calculator.