In Ohm's Law context, a combination circuit should be analyzed by which method?

• A. A circuit that contains only series elements is analyzed first
• B. A circuit with only parallel elements is analyzed first
• C. A circuit that alternates between series and parallel components is analyzed by Kirchhoff's laws only
• D. Break the circuit into the simplest series and parallel sections and reduce step by step

Answer: (A)

When solving a mixed resistor network, the best approach is to simplify by breaking the circuit into the simplest series and parallel sections and reducing them step by step. This keeps the problem manageable and lets you replace parts of the circuit with their equivalent resistances as you go.

In a series group, the current is the same through each component and the resistances add. In a parallel group, the voltages are the same across each branch and the individual conductances (reciprocals of resistance) add. By identifying a clearly series or clearly parallel block, you replace that block with its equivalent resistance, redraw the circuit, and repeat until you’re left with a single resistance. Once you have the overall equivalent, you can apply Ohm’s Law to find currents and voltages as needed.

The idea that you should only start with circuits that contain all-series elements isn’t generally practical for combination circuits, because many networks begin with parallel branches. The systematic method is to isolate the simplest section (whether series or parallel), reduce it, and proceed step by step. Using this approach consistently leads to the correct solution and connects directly to Ohm’s Law.