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 for a resistor?

  Directly proportional as long as temperature is constant
• How does the current through a filament lamp behave compared to a resistor?

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

  The resistance increases
• 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 happens 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 look?

  No current flows in reverse direction; increases in forward direction
• Where can you commonly find LEDs?

  In cameras, light bulbs, and televisions
• What is the symbol for an LED?

  Similar to a diode but with arrows
• Why are LEDs considered energy efficient?

  They emit light with low energy consumption