The Microphone

• What effect is discussed in relation to the moving coil microphone?

  The generator effect
• What happens when a conducting wire passes through a magnetic field?

  A potential difference is induced
• What is required for a current to be induced in a wire?

  The wire must be part of a complete circuit
• How is the generator effect utilized in a moving coil microphone?

  The coil moves through a magnetic field
• What is attached to the coil of wire in a moving coil microphone?

  A thin sheet of plastic called a diaphragm
• What happens when sound waves hit the diaphragm?

  They cause it to vibrate
• What does the movement of the coil through the magnetic field induce?

  A potential difference across the ends of the wire
• How does the potential difference behave as the coil moves?

  It switches direction as the coil moves
• What is the relationship between the frequency of the changing potential difference and the sound waves?

  They are the same frequency
• Where is the changing pattern of potential difference sent after being induced?

  To an amplifier
• What happens to the sound after it passes through the amplifier?

  It massively increases in volume
• What is the structure of a moving coil microphone?

  • Coil of wire
  • Diaphragm (thin plastic sheet)
  • Permanent magnet
• What is the process of sound wave conversion in a moving coil microphone?

  1. Sound waves hit the diaphragm
  2. Diaphragm vibrates
  3. Coil moves through magnetic field
  4. Potential difference is induced
  5. Signal is amplified
• What are the key components involved in the operation of a moving coil microphone?

  • Diaphragm
  • Coil of wire
  • Permanent magnet
  • Induced potential difference
  • Amplifier