Free Science Lessons: Current-Potential Difference Graph for Diodes and LEDs

Key Concepts

Resistor: The current through a resistor is directly proportional to the potential difference, provided the temperature remains constant.
Filament Lamp: The current is not directly proportional to the potential difference because the filament heats up, increasing resistance.

Definition: A diode is a component where the current flows in one direction only.
Symbol: Learn the symbol for a diode.
Functionality:
- In the forward direction, the diode allows current to pass.
- In the reverse direction, the diode has a very high resistance, preventing current flow.
Graph: The current-potential difference graph shows that no current flows in the reverse direction, while in the forward direction, current increases with potential difference.
Usefulness: Diodes control the flow of current in circuits.

Definition: Similar to a normal diode but emits light when current flows through.
Symbol: Similar to a diode symbol but with arrows indicating light emission.
Functionality:
- Allows current to flow only in the forward direction.
- Emits light when operational.
Applications:
- Found in various electronic gadgets: camera flashes, LED light bulbs, LED televisions.
- Known for being an energy-efficient light source.

Review questions on diodes and LEDs using the vision workbook available from the link provided in the lesson.

You should now be able to:
- Describe and explain the shape of the current-potential difference graph for a diode.
- Define what a light emitting diode is and its practical applications.