What is the voltage rule for parallel circuits?

What is the voltage rule for parallel circuits?

• A. The voltage across each branch varies with time
• B. The current is the same across each branch
• C. The voltage is the same across each branch
• D. The voltage drops across the branches sum

Answer: (C)

In a parallel circuit, all branches are connected to the same two nodes, so the potential difference between those nodes—the available voltage—is the same for every branch. That means the voltage across each branch is identical, equal to the source voltage (assuming an ideal voltage source and negligible wiring resistance). The current, however, can differ in each branch because it depends on each branch’s resistance via Ohm’s law (I = V/R). So you can have one branch drawing more current and another drawing less, all while each branch still has the same voltage across it. The other statements don’t fit this behavior: the voltage across branches isn’t inherently varying with time in a simple steady parallel circuit; the current isn’t the same in every branch (it splits according to each branch’s resistance); and you don’t add the voltages of the branches together—the same voltage appears across all branches.

In a parallel circuit, all branches are connected to the same two nodes, so the potential difference between those nodes—the available voltage—is the same for every branch. That means the voltage across each branch is identical, equal to the source voltage (assuming an ideal voltage source and negligible wiring resistance). The current, however, can differ in each branch because it depends on each branch’s resistance via Ohm’s law (I = V/R). So you can have one branch drawing more current and another drawing less, all while each branch still has the same voltage across it.

The other statements don’t fit this behavior: the voltage across branches isn’t inherently varying with time in a simple steady parallel circuit; the current isn’t the same in every branch (it splits according to each branch’s resistance); and you don’t add the voltages of the branches together—the same voltage appears across all branches.