From DT Online

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Microphones convert sound energy into electrical energy.

Features and Applications

There are a number of types :-

Moving coil - similar in construction to a loudspeaker but working in reverse. The sound vibrates the diaphragm which in turn moves the coil and induces an emf into it.

Crystal or Piezo - sounds hitting the Piezo material causes minute currents to flow.

""Ribbon"" - a lightweight foil ribbon is suspended in a strong magnetic field. When sound hits the ribbon it vibrates within the magnetic field and generates a small current.

Capacitor - a lightweight charged diaphragm is positioned close to another charged plate. When sound hits the diaphragm it varies the gap and hence the capacitance. As the microphone needs to be polarised (i.e. have a fixed voltage applied across it), varying the capacitance also varies the voltage and therefore gives a true representation of the sound at the output.

DT Online Buyers' Guide
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Intermittent Buzzer Beep DC3-24V Active Buzzer Beep DC 3-24V Miniature Buzzer 3V Mini Music Loudspeaker 29mm 4pcs 57mm Loudspeaker 8 ohm 1watt Piezo Transducers with Flying Lead 20mm 27mm Piezo Element 3V Piezo Buzzer Continuous Sound (x20) Stereo Earbuds with Mic and Volume Control