Learning Event 2:
DESCRIBE USES AND OPERATION OF THE CERAMIC AND DYNAMIC MICROPHONES
1. Ceramic Microphones. Ceramic microphones are, characteristically, a sturdy
instrument. This microphone is used in conjunction with walkie talkies, dictating
machines and public address systems. The ceramic microphone is widely used in
areas of high temperature and high humidity. The impedance of this type of
microphone is normally 1 to 5 megahoms.
2. Dynamic Microphones. This type of microphone employs a small diaphragm and a
voice coil, similar to a dynamic loudspeaker, moving in an intense permanent
a. Sound waves striking the coil cause it to move within the magnetic field,
generating a voltage proportional to the sound pressure exerted on the diaphragm.
This microphone is also referred to as a pressure, or moving coil, microphone;
typical examples of this design are shown in Figures 36a and 36b.
Figure 36a. Western Electric
Figure 36b. Alteclansing
630B dynamic (movingcoil)
Model 633a/c dynamic (moving
microphone
coil) microphone
b. Figure 37 shows a cross section view of the 630B microphone. The
diaphragm (A) is of Dural, approximately 0.5 mils in thickness, and weighs 25
milligrams. Cemented to the rear of the diaphragm is a voice coil (B).
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