Chapter 35, Problem 9A

What happens to the total circuit resistance when more devices are added to a series circuit? To a parallel circuit?

To determine

The effect on the total circuit resistance due to addition of more devices in a series circuit and a parallel circuit.

Explanation of Solution

Introduction:

In a series circuit, the current remains same through each device while the voltage is different across each device. The voltage drop varies with the resistance of the device.

In a parallel circuit, the voltage remains same but the current varies due to resistance.

In a series circuit, the equivalent resistance of the circuit is the sum of the resistance of each device. When more devices are added to it, the resistance are added. Therefore, the total circuit resistance increases.

In a parallel circuit, the devices are connected in parallel and the current splits across each device. When more devices are added to it, the number of parallel branches increases and the total circuit resistance decreases.

Conclusion:

The total circuit resistance increases in a series circuit and decreases for parallel circuit.