# Definition:Electric Charge/Quantum

## Definition

Electric charge has been demonstrated to be quantized.

The quantum of electric charge is the elementary charge $\E$:

$\E = 1.60217 \, 6634 \times 10^{−19}$ coulombs exactly.

This is so small that to all practical purposes in everyday measurement of electricity, it can be treated as though it were continuous.

### Symbol

The symbol used to denote the elementary charge is usually $\E$ or $e$.

The preferred symbol on $\mathsf{Pr} \infty \mathsf{fWiki}$ is $\E$.

## Examples

### $60 \ \mathrm W$ Bulb at $200 \ \mathrm V$

Consider a $60 \ \mathrm W$ light bulb running at $200 \ \mathrm V$.

Approximately $2 \times 10^{18}$ units of elementary charge flow along the filament of the light bulb every second.

## Technical Note

The $\LaTeX$ code for $\E$ is \E .