# Definition:Electric Current

## Definition

Electric current is the physical process caused by the flow of electrically charged particles, usually electrons.

Thus it is defined as the rate of flow of electric charge:

$I = \dfrac {\d Q} {\d t}$

It is often treated as a scalar quantity, but more properly it is a vector quantity whose direction is that in which the electrically charged particles are traveling.

### Symbol

The usual symbol used to denote an electric current when it is necessary to treat it as a vector quantity is $\mathbf J$.

When only its scalar magnitude is being discussed, the symbol $I$ is usually used.

### Dimension

Electric current is one of the fundamental dimensions of physics.

In dimensional analysis it is assigned the symbol $\mathsf I$.

### Units

The SI unit of electric current is the ampere $\mathrm A$.