# 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 symbols $I$ or $i$ are 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 base unit of electric current is the ampere $\mathrm A$.

In the CGS unrationalised electromagnetic system, the base unit of electric current is the abampere $\mathrm {abA}$.

In the CGS unrationalised electrostatic system, the base unit of electric current is the statampere $\mathrm {statA}$.

### Conversion Factors

 $\ds$  $\ds 1$ amperes $\ds \text {corresponds to}$  $\ds 10^{-1}$ abampere (or e.m.u., or biot) $\ds \text {corresponds to (approximately)}$  $\ds 3 \times 10^9$ statampere (or e.s.u. of electric current)

## Also see

• Results about electric current can be found here.