1. . An amplifier that operates in the linear region at all times is
(A) Class A
(B) Class B
(C) Class AB
(D) Class C
2. . A certain class A amplifier delivers 5W to a load with an input signal power of 100 mW. The power gain is
(A) 100
(B) 50
(C) 250
(D) 5
3. . The peak current a class A power amplifier can deliver to a load depends on the
(A) Maximum rating of the power supply
(B) Quiescent current
(C) Current in the bias resistor
(D) Size of the heat sink
4. . For maximum output, a class A power amplifier must maintain a value of quiescent current that is
(A) One-half the peak load current
(B) Twice the peak load current
(C) At least as large as the peak load current
(D) Just above the cutoff value
5. . A certain class A power amplifier has VCEQ = 12V and ICQ = 1A. The maximum signal power output is
(A) 12 W
(B) 6 W
(C) 1 W
(D) 0.707 W
6. . The efficiency of a power amplifier is the ratio of the power delivered to the load to the
(A) Input signal power
(B) Power from the DC power supply
(C) Power dissipated in last stage
(D) None of the above
7. . The maximum efficiency of a class A power amplifier is
(A) 25%
(B) 50%
(C) 79%
(D) 98%
8. . The transistor in a class B amplifier are biased
(A) In cutoff
(B) In saturation
(C) At midpoint of load line
(D) Right at cutoff
9. . Crossover distortion is a problem for
(A) Class A amplifiers
(B) Class B amplifiers
(C) Class AB amplifiers
(D) Class C amplifiers
10. . A BJT class B push-pull amplifier with no transformer coupling uses
(A) Two npn transistors
(B) Complementary pair transistors
(C) Two pnp transistors
(D) Direct
11. . The maximum efficiency of a class B push-pull amplifier is
(A) 25 %
(B) 50 %
(C) 79 %
(D) 98 %
12. . The output of a certain two-supply class B push-pull amplifier has a VCC of 20 V. If the load resistance is 50 Ω, the value of IC(sat) is
(A) 5 mA
(B) 0.4 A
(C) 4 mA
(D) 40 mA
13. . The maximum efficiency of a class AB amplifier is
(A) Higher than class B
(B) Same as class B
(C) Same as class A
(D) Slightly less than class B
14. . The power dissipation of class C amplifier is normally
(A) Less than class A
(B) Less than class B
(C) Less than class AB
(D) Greater than classes A, B or AB
15. . The transistor in a class C amplifier conducts for
(A) More than 180° of the input cycle
(B) One-half of the input cycle
(C) A very small percentage of the input cycle
(D) A complete 360°