15.
Several types of telephone receivers are used to convert the electrical waves back to sound wave. The type of
receiver most commonly used for this purpose is the:
a.
dynamic type.
b.
moving-coil type.
c.
moving-conductor type.
d.
magnetic-diaphragm type.
SITUATION
Assume that the telephone receivers used in your central office telephone system are identical with the receiver
shown in figure 19.
Exercises 16 and 17 are based on the above situation.
16.
Upon analyzing the construction of the receiver, you determine that the purpose of the circular magnet ring is to:
a.
permit the use of smaller electromagnets so that the physical size of the receiver can be reduced.
b.
c.
prevent the diaphragm seat from vibrating at the same frequency as the membrane.
d.
permit the use of larger coils for more current handling capabilities.
17.
During your analysis of the telephone construction, you discover that a varistor (fig. 19) is connected to the
receiving circuit. The purpose of the varistor is to:
a.
eliminate the need of acoustic resistance.
b.
protect the user from acoustics levels.
c.
prolong the life of the membrane.
d.
eliminate sidetone in the receiver.
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