In a series circuit, the total resistance across all of the components (the 'net resistance') increases as more components are added.
The two resistors have the same current through them. The potential difference across them will be different if they have different resistances. The total resistance ( ) for this circuit is .
Example: A 2 Ω resistor is placed in series with a 6 Ω resistor. What is the total resistance?
In a parallel circuit, the net resistance decreases as more components are added, because there are more paths for the current to pass through.
The two resistors have the same potential difference across them. The current through them will be different if they have different resistances.
The total current in the circuit is the sum of the currents through each branch.