55. Parallel Circuits

1. Potential Difference (Voltage)

In a parallel circuit where each loop contains only one component, every component receives the full source potential difference.

  • The Rule: VTotal = V1 = V2 = ...

  • Example: If a battery provides 12V, every individual loop in the parallel circuit will have a potential difference of 12V.

2. Current

Unlike in a series circuit, the total current is shared between the different loops.

  • The Rule: ITotal = I1 + I2 + ...

  • Distribution: The way current splits depends on the resistance of the components in each loop.

    • Loops with lower resistance will have a higher current flowing through them.

    • Loops with higher resistance will take a lower share of the current.

  • Analogy: Think of water flowing down a hill; most water will take the path of least resistance.

3. Resistance

The resistance behavior in parallel circuits is unique: the more components (loops) you add in parallel, the lower the total resistance of the circuit becomes.

  • Why? Adding another loop provides an additional path for the current to flow. Even if that new path has high resistance, it still makes it easier for the total current to flow around the circuit overall, effectively reducing the total resistance.

4. Summary Table for Parallel Circuits

Property

Rule

Potential Difference (V)

The same across all parallel loops.

Current (I)

Shared between loops (Sum of currents in loops = Total current).

Resistance (R)

Adding loops in parallel decreases the total resistance.

5. Series vs. Parallel Comparison

Feature

Series

Parallel

Loops

Single loop

Multiple loops

Broken Component

Whole circuit stops

Only that loop stops

Current

Same everywhere

Shared between loops

Voltage

Shared between components

Full source voltage for each loop