A condenser microphone is a very simple mechanical system, with almost no moving parts compared to other microphone designs. It is also one of the oldest microphone types, dating back to the early 1900s. A condenser capsule is simply a thin, stretched conductive diaphragm positioned close and a parallel to a metal disk called a “backplate.” This arrangement effectively produces a capacitor, which is given its electric charge by an external voltage source. In many cases, this source is phantom power, but certain condenser mics (particularly tube mics) have dedicated power supply units.
In a condenser mic, when sound pressure acts on the diaphragm, the diaphragm vibrates slightly in response to the waveform. This causes the capacitance to vary in a like manner, which causes a variance in output voltage. This voltage variation is the signal output of the microphone. There are many different types of condenser microphones, but they are all based on these basic operating principles.
