Transcript CONDENSER-MICROPHONESx

CONDENSER MICROPHONES
Victor Dagenais-Martin, Charles Duclos and Adam Joober
FUNCTIONING OF A CONDENSER MIKE
FUNCTIONING OF A CONDENSER MIKE
SEE https://www.youtube.com/watch?v=Mxp3eCCQyas for explanation
FUNCTIONING OF A CONDENSER MIKE
• A condenser microphone relies on the variations of pressure that sound waves produce to
convert sound into an electrical signal. A flexible diaphragm (that is, a flexible plate) oscillates
inside the condenser microphone back and forth according to pressure variations caused by
soundwaves. This plate is part of a set of parallel plates, of which the back plate is stationary,
which has a capacitance (C) ; this capacitance changes in magnitude according to the variable
distance d between the plates.
• (Electric fields and equipotential lines are also affected by distance variation; possibly the final
voltage could be drawn from these formulas?)
• For a fixed number of charges (Q) a different voltage is issued according to the variation in
capacitance (C) ; thus the electric potential (V) of the electric current in the microphone varies.
This variation in electric potential (V) enables to reproduce the sound according to the second
formula, of which parameters ε0, A, 𝑑, and Δ𝑡 are known.
CONDENSER MICROPHONE FORMULAS
•𝐶=
𝑄
𝑉
=
• 𝑖 signal =
ε0𝐴K
𝑑
Δ𝑄
Δ𝑡
= ε0𝐴V
1
𝑑
Δ{ }
Δ𝑡
This last equation enables to convert sound waves pressure on the
flexible diaphragm in electrical potential (V) measured across the
resistor.
• Source: http://hyperphysics.phy-astr.gsu.edu/hbase/audio/mic2.html#c3