In a parallel circuit, how is voltage and current distributed?

• A. The current through each branch is equal, and the branch voltages sum to the source voltage.
• B. The voltage across all branches varies; branch currents are fixed.
• C. The voltage across each branch is the same; currents in branches add to equal the source current.
• D. The total current is the same as the source current, regardless of branches.

Answer: (C)

In a parallel circuit, the voltage across each path is the same as the source voltage. That’s because each branch is directly connected across the supply. The current in each branch, however, depends on that branch’s resistance (or impedance) and can be different from branch to branch, since I = V/R for each branch. The total current drawn from the source is the sum of all the branch currents, so I_total = I1 + I2 + … + In. This is why the statement that the voltage across each branch is the same and the currents in the branches add to equal the source current best describes how voltage and current distribute in parallel circuits. For example, with two branches, each sees the same voltage, but if one branch has a lower resistance it carries more current, and the two currents add together to make the total from the source.