# Current, charge and time

Electrical current is defined by how much electric charge has been transferred per second, giving the following :

$current=\frac{charge}{time}$

Rearranging this we get:

$charge = current \times time$

The symbol for charge is $$Q$$, it is measured in coulombs ($$C$$).

The symbol for current is $$I$$, it is measured in amperes ($$A$$).

The symbol for time is $$t$$, it is measured in seconds ($$s$$).

This gives the relationship:

$Q = I \times t$

## Example

Question

Calculate the charge that passes through a lamp in 2 minutes if the current is $$1.5A$$?

To calculate the charge, you need to use the following relationship:

$charge = current \times time$

Remember to convert minutes into seconds by multiplying by 60

$Q = 1.5 \times (2 \times 60) = 180C$