3. Despite the fact that sound-powered transmitters and receivers are constructed identically, their armature
motivation is different. The armature of the receiver is moved by
a. sound waves.
b. the diaphragm.
d. magnetic attraction and repulsion.
4. At the end of each complete cycle of current, the armature of the sound-powered receiver returns to its in-
between position of rest. The armature is returned to this position by a force applied by the
c. mechanical coupling.
b. permanent magnet.
d. generated sound waves.
5. The signaling circuit of the sound-powered telephone (fig. 206, TM 11-678) is connected across the
transmission line during conversation, but the transmission loss through this circuit is small because of the high
a. the ringer.
b. capacitor C2.
d. the neon lamp.
6. Ringing current for the sound-powered telephone to signal the operator or distant party is provided by a
local generator (fig. 206, TM 11-678). During signaling, ringing current is prevented from entering the local
a. switch S1.
c. capacitor C1.
b. switch S2.
d. capacitor C2.
7. When compared with the battery-operated telephone system, a disadvantage of the sound-powered
telephone system is
a. less rugged components.
c. shorter transmission range.
d. heavier and bulkier telephone sets.
8. Telephone Set TA-I/PT is a sound-powered telephone designed for field use. It has an effective signaling
and transmission range over Wire WD-1/TT of approximately
a. 4 miles (6.44 km).
c. 22 miles (35.42 km).
b. 14 miles (22.54 km).
d. 29 miles (46.69 km).