diodes and LEDs

• What is a light emitting diode (LED)?

  A diode that emits light when current flows
• Why are diodes useful in circuits?

  They control the flow of current in one direction
• What is the relationship between current and potential difference in a resistor?

  Current is directly proportional to potential difference
• How does the current through a filament lamp behave?

  It is not directly proportional to potential difference
• What happens to the resistance of a filament lamp as it gets hot?

  The resistance increases as it gets hot
• What is the key feature of a diode?

  Current flows in one direction only
• What does the arrow in the diode symbol indicate?

  The direction of conventional current flow
• What occurs when the current flows in the reverse direction through a diode?

  The diode does not allow current to pass through
• How does the current potential difference graph for a diode behave in the reverse direction?

  No current can flow in the reverse direction
• What happens to the current in the forward direction for a diode?

  The current increases as potential difference increases
• Where can you commonly find LEDs?

  In electronic gadgets like cameras and light bulbs
• What is the symbol for an LED?

  It is similar to a diode but has arrows
• Why are LEDs considered energy efficient?

  They emit light with low energy consumption
• What is the main difference between a diode and an LED?

  An LED emits light when current flows
• What are the characteristics of a diode and an LED?

  • Diode:
  • Allows current to flow in one direction
  • High resistance in reverse direction
  • LED:
  • Similar to a diode
  • Emits light when current flows
  • Energy efficient source of light
• What are the uses of diodes and LEDs in everyday life?

  • Diodes:
  • Control current flow in circuits
  • LEDs:
  • Used in cameras, light bulbs, televisions
  • Provide energy-efficient lighting