Overview
This lecture explains how potential difference (voltage) behaves in parallel circuits and demonstrates how to calculate it using examples.
Potential Difference in Circuits
- Potential difference (voltage) measures energy transferred per coulomb of charge.
- In series circuits, potential difference is split between components.
- In parallel circuits, there are separate branches with current dividing between them.
Measuring Potential Difference in Parallel Circuits
- A voltmeter measures the potential difference across components or cells.
- In a parallel circuit, the potential difference across the cell is equal to the potential difference across each branch.
- For example, if the cell has 6 volts, both top and bottom branches also have 6 volts potential difference.
Key Facts About Parallel Circuits
- All components connected in parallel have the same potential difference across them.
- If one branch or the cell has a certain potential difference, every other parallel branch shares that value.
Example Questions and Calculations
- If the bottom lamp's potential difference is 12 volts, the top lamp and the cell also have 12 volts potential difference.
- For a parallel branch with two lamps in series (e.g., one lamp at 7 V and the other at 2 V), the total across that branch is 9 V, matching the other parallel branch and the cell.
Key Terms & Definitions
- Potential Difference (Voltage) — the energy transferred per unit charge (measured in volts, V).
- Parallel Circuit — a circuit with branches where each branch gets the same potential difference.
- Series Circuit — a circuit where components share the potential difference from the cell.
Action Items / Next Steps
- Practice more questions on potential difference in parallel circuits from the suggested revision workbook.
- Review definitions of series and parallel circuits.