Diodes and Light-Emitting Diodes (LEDs)

Current-Potential Difference Graphs

• We have previously discussed the graphs for resistors and filament lamps.
• Resistor:
• Current is directly proportional to potential difference (as long as temperature remains constant).
• Filament Lamp:
• Current is not directly proportional to potential difference due to increasing resistance as the filament heats up.

Diodes

• A diode is an electronic component that allows current to flow in one direction only.
• Key Feature:
• High resistance in the reverse direction prevents current flow.
• Symbol for Diode:
• Diode symbol includes an arrow indicating the direction of conventional current.
• Current flows forward (from the anode to cathode).
• Current-Potential Graph:
• No current flows in the reverse direction.
• In the forward direction, current increases with increasing potential difference.
• Utility:
• Used to control current flow in electrical circuits.

Light-Emitting Diodes (LEDs)

• LED is a type of diode that emits light when current flows through it.
• Symbol for LED:
• Similar to a diode but with arrows coming off to indicate light emission.
• Like diodes, LEDs permit current flow only in the forward direction.
• Energy Efficiency:
• LEDs are highly energy-efficient compared to traditional light sources.
• They are commonly used in various electronic devices (e.g., cameras, light bulbs, televisions).

Conclusion

• Revision Material:
• For more practice and questions, refer to the revision workbook mentioned in the video.
• By the end of this video, you should be able to explain the current-potential difference graph for diodes and the concept of LEDs, including their usefulness.