Lecture Notes: Potential Difference in Series Circuits

Introduction to Series Circuits

• A series circuit is a simple loop where components are arranged one after the other.

Understanding Potential Difference

• Potential difference is about energy transfer in a circuit.
• The potential difference across a point in the circuit indicates the amount of energy transferred to or from a coulomb of charge between two points.

Current and Electron Flow

• Current consists of electrons flowing through the circuit.
• Electrons gain energy when passing through cells, which is then transferred to components like bulbs.

Coulomb of Charge

• A coulomb of charge consists of millions of electrons.
• As it travels through the circuit, a coulomb of charge picks up energy from the cells.

Example 1: Identical Components

• Circuit with identical bulbs:
  • Total potential difference across the cells: 4 volts.
  • Each bulb receives an equal amount of energy:
    • Potential difference across each bulb: 2 volts.
    • Total potential difference: 2V + 2V = 4V (equals the supply).

Example 2: Different Components

• Circuit with a bulb and a motor:
  • Total potential difference across the cells: 4 volts.
  • Energy allocation:
    • Potential difference across bulb: 1 volt (1 joule of energy from the charge).
    • Potential difference across motor: 3 volts (3 joules of energy from the charge).
    • Total potential difference: 1V + 3V = 4V (equals the supply).

Key Takeaways

• Energy is shared between components in a series circuit.
• The potential difference across all components in series adds up to the potential difference of the supply.
• The energy shared among components must total the energy given out by the supply.