# Formula Electric current (definition) Electric charge    Time

## Electric current

Unit
Electric current is the amount of charge $$Q$$ that crosses the cross-sectional area of a wire within a time period $$t$$. Electric current is therefore charge per time.

## Electric charge

Unit
This is the amount of charge that has passed through the cross-sectional area of a wire within the time $$t$$.

If the individual (positively) charged particles carry the charge $$q$$ and $$N$$ particles have passed through the cross-sectional area in the time $$t$$, then the charge passed through:$Q ~=~ N \, q$

## Time

Unit
Time period during which the charges were counted through a cross-sectional area.