The condenser
microphone works on the principle that
a
voltage change occurs over a
capacitor
(
electric condenser was an older name for
capacitor)
when the
capacitance is
changed while the
charge is
constant.
Buildup of a condenser microphone:
Supporting
frame
:
M -----
e :----
m : |
b : |
r -- : D | -- metal electrode
a : |
n :---|
e |---|
O O
connectors
(D=dielectric)
The
membrane is made from a
thin foil of
conductive
material. The
dielectrical medium is usualy air. This
type of
microphone must be connected to a powersource. This is
to
charge the
capacitor formed by the
membrane and
electrode
When a
soundwave hits the membrane it will
vibrate and the
capacitance of the
microphone varies, and thus the voltage
over it. the
voltage variation is an
analog representation
of the
soundwave.
A variation of this microphone is the
electret condenser
microphone. It has a
membrane made of
electret. It doesn't
need a
charging powersource, since the
electric field from the
electret
does this
job.
The
electret microphone is easier to use and cheaper than
the
condenser microphone but has a poorer frequency '
reproduction'
(it has a lower sensitivity to low
frequency sound).
The
condenser microphone is used in
professional microphones
due to bether
sound quality than
dynamic microphones.