audio signal the reverse occurs, which is typical of push-pull circuits.
Capacitor C1 improves the amplifier's frequency response and stabilizes
its output. Capacitor C1 is chosen so that the combination of C1 and T2
does not resonate within the audio-frequency band to be passed by the
amplifier. Negative feedback (degeneration) is not necessary because the
push-pull circuit cancels most of the distortion that is created within
the transistors.
LESSON EXERCISES
In each of the following exercises, select the ONE answer that BEST completes
the statement or answers the question
Indicate your solution by circling the
letter opposite the correct answer in the subcourse booklet.
1. Voltage and power amplifiers are used together in high-power audio
amplifiers. Tubes selected for the final stage of a high-powered audio amplifier
are characterized by a high
a. amplification factor and small plate current.
b. amplification factor and large plate current.
c. transconductance and large plate current.
d. transconductance and small plate current.
2. One of the characteristics of the resistance-coupled amplifier circuit shown
in B of figure 193, TM 11-665, is:
a. the value of Rg is usually smaller than that of RL
b. a coupling network always adds to the stage gain.
c. the output voltage is reduced when RL is made too large.
d. a frequency response falls off rapidly at frequencies above the resonant
peak.
3. For coupling between AF stages, transformer coupling is usually preferred to
resistance or impedance coupling because
a. transformer coupling is inexpensive.
b. the transformer can provide additional gain.
c. the amplification can easily be made uniform over the entire AF range.
d. due to self-resonance,
there
is
little
distortion
in
a
322 L4
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