Numerical Example: Resistors in Series

We are given a circuit as shown above. It has two resistors connected in series to each other.

Find the current flowing through the resistors.

Solution

First we find the equivalent resistance.

Equivalent R = 2 +4 = 6 ohms

The equivalent resistance means that we can replace the two resistors with one.

Now we can apply our simple formula: V = I x R

Which gives us: I = V/R = 12/6 = 2 Amps

This means that 2 amps current will flow in both of the resistors. If you consider the top figure, then 2 amps will flow through one resistor and then the other, before returning back to the battery. If you consider the bottom figure, two amps will flow through the equivalent resistance.