15. Telephone transmitters generally pick up and transmit undesirable background noises. One transmitter,
however, that is most effective in canceling these noises is the
a. positional transmitter.
b. differential transmitter.
16. Several types of telephone receivers are used to reconvert the electrical waves to sound waves. The type
of receiver most commonly used for this purpose is the
a. dynamic type.
c. moving-conductor type.
b. moving-coil type.
d. magnetic-diaphragm type.
17. What is the purpose of the permanent magnet in a telephone receiver?
a. To eliminate the need for poling
b. To permit the use of smaller electromagnets
c. To extend the transmission range of the telephone
d. To prevent the diaphragm from vibrating at twice the received frequency
18. Many modern telephones have a varistor connected in the receiving circuit and installed in the handset.
One of the purposes of this varistor is to
a. eliminate sidetone in the receiver.
b. make it unnecessary to pole the receiver.
c. prolong the life of the permanent magnet.
d. separate the transmitting circuit from the receiving circuit.
19. Telephone servicemen use diagrams when connecting equipment. The type of diagram that is best suited
for checking a hookup after it is made is the
a. block diagram.
c. pictorial diagram.
b. wiring diagram.
d. schematic diagram.
20. One of the recommended procedures for learning to read and understand schematic diagrams is to
b. circuit diagram.
c. physical position of each component.
CHECK YOUR ANSWERS WITH LESSON SOLUTION SHEET # 1, PAGE 28.