Parallel circuits in basic electronics Which quantity is considered the common reference (i.e., the same across every branch) in any parallel circuit?

Introduction / Context:
In electrical engineering, recognizing what is common and what divides in parallel circuits is fundamental for troubleshooting and design. This concept underpins how we size components, measure quantities, and predict behavior when loads change.

Given Data / Assumptions:

• The network is an ideal parallel circuit with ideal conductors.
• All branches are connected directly across the same two nodes of a voltage source.
• Component non-idealities like lead resistance are neglected for clarity.

Concept / Approach:
By definition, elements are in parallel if both of their terminals are connected to the same two nodes. That guarantees the same potential difference across each branch. While the branch currents may differ (depending on branch resistance or impedance), the voltage across each branch equals the source voltage at those nodes.

Step-by-Step Solution:

Verification / Alternative check:
Use Ohm’s law on two different branches: I1 = V/R1 and I2 = V/R2. The same V appears in both relations; only currents vary with resistance. Measurements with a voltmeter across any branch show the same reading (within tolerances).

Why Other Options Are Wrong:

• Current: divides among branches according to their impedances.
• Power: differs per branch because P = V^2/R or P = I^2*R.
• Resistance: each branch has its own value; the equivalent resistance is the parallel combination, not a common per-branch value.

Common Pitfalls:
Confusing series and parallel rules; in series, current is common and voltage divides, whereas in parallel, voltage is common and current divides.

Final Answer:
Voltage