E7B
Amplifier circuits: Class A, Class AB, Class B, Class C, amplifier
operating efficiency (ie, DC input versus PEP), transmitter final
amplifiers; amplifier circuits: tube, bipolar transistor, FET
E7B01
(A)
For
what portion of a signal cycle does a Class AB amplifier operate?
A. More than 180 degrees but
less than 360 degrees
B. Exactly 180 degrees
C. The entire cycle
D. Less than 180 degrees
E7B02
(C)
Which
class of amplifier provides the highest efficiency?
A. Class A
B. Class B
C. Class C
D. Class AB
E7B03
(A)
Where
on the load line should a solid-state power amplifier be operated for best
efficiency and stability?
A. Just below the saturation
point
B. Just above the saturation point
C. At the saturation point
D. At 1.414 times the saturation point
E7B04
(C)
How can
parasitic oscillations be eliminated from a power amplifier?
A. By tuning for maximum SWR
B. By tuning for maximum power output
C. By neutralization
D. By tuning the output
E7B05
(B)
How can
even-order harmonics be reduced or prevented in transmitter amplifiers?
A. By using a push-push amplifier
B. By using a push-pull
amplifier
C. By operating Class C
D. By operating Class AB
E7B06
(D)
What
can occur when a nonlinear amplifier is used with a single- sideband phone
transmitter?
A. Reduced amplifier efficiency
B. Increased intelligibility
C. Sideband inversion
D. Distortion
E7B07
(C)
How can
a vacuum-tube power amplifier be neutralized?
A. By increasing the grid drive
B. By feeding back an in-phase component of the
output to the input
C. By feeding back an
out-of-phase component of the output to the input
D. By feeding back an out-of-phase component of
the input to the output
E7B08
(B)
What
tank-circuit Q is required to reduce harmonics to an acceptable level?
A. Approximately 120
B. Approximately 12
C. Approximately 1200
D. Approximately 1.2
E7B09
(B)
In
Figure A7-1, what is the purpose of R1 and R2?
A. Load resistors
B. Fixed bias
C. Self bias
D. Feedback
E7B10
(D)
In
Figure A7-1, what is the purpose of C3?
A. AC feedback
B. Input coupling
C. Power supply decoupling
D. Emitter bypass
E7B11
(D)
In
Figure A7-1, what is the purpose of R3?
A. Fixed bias
B. Emitter bypass
C. Output load resistor
D. Self bias
E7B12
(A)
In
Figure A7-2, what is the purpose of R?
A. Emitter load
B. Fixed bias
C. Collector load
D. Voltage regulation
E7B13
(A)
In
Figure A7-2, what is the purpose of C2?
A. Output coupling
B. Emitter bypass
C. Input coupling
D. Hum filtering
E7B14
(B)
What is
the purpose of D1 in the circuit shown in Figure A7-3?
A. Line voltage stabilization
B. Voltage reference
C. Peak clipping
D. Hum filtering
E7B15
(C)
What is
the purpose of Q1 in the circuit shown in Figure A7-3?
A. It increases the output ripple
B. It provides a constant load for the voltage
source
C. It increases the
current-handling capability
D. It provides D1 with current
E7B16
(A)
What is
the purpose of C2 in the circuit shown in Figure A7-3?
A. It bypasses hum around D1
B. It is a brute force filter for the output
C. To self resonate at the hum frequency
D. To provide fixed DC bias for Q1