Professional studio recording typically employs large diaphragm condenser microphones for their ability to accurately translate an acoustic pressure wave into a potential. Although the engineering involved in such a microphone is elegant and results in a costly product, the underlying principle is simply that a change in capacitance will result in a corresponding change in voltage.

Capacitance is defined as

C=qV,

where C is capacitance, q is charge on the plates, and V is the potential measured across the plates. For a simple parallel plate capacitor,

C=ε0κAd,

where A is the area of the plates and d is the distance between plates. ε0 and κ are the permittivity of free space and dielectric constant, respectively. For a constant charge, rearranging these equations results in

V=qdε0κA,

where the voltage across the...

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