P4.2.6 - Microphones and Loudspeakers

Question 1

Describe how a microphone works.

Answer 1

Sound wave hits the diaphragm. Areas of high pressure, compressions, push the diaphragm in, and areas of low pressure, rarefactions, push it out. As the diaphragm moves, the coil does which induces a potential difference.

Question 2

Describe how a carbon microphone works.

Answer 2

Sound waves hit the diaphragm which changes the resistance of the carbon granules behind it. A current passing through the carbon increases or decreases as the current changes

Question 3

Describe how a loudspeaker works.

Answer 3

The changing potential difference produces a changing current. The current produces a force on a coil of wire because it is in a magnetic field. The cone does not spin but moves in and out.