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ECE Objective Questions { BJT Amplifiers and Transistor }

22. A class-B amplifier has high theoretical efficiency of 78.5 percent because
A. it is biased almost to saturation
B. its quiescent current is low
C. its output is an exact replica of its input
D. it is biased well below cut-off

23. Crossover distortion occurs in ? amplifiers.
A. push-pull
B. class-A
C. class-B
D. class-AB

24. The main use of a class-C amplifier is
A. as an RF amplifier
B. as stereo amplifier
C. in communication sound equipment
D. as distortion generator

25. An amplifier is said to suffer from distortion when its output is
A. low
B. different from its input
C. noisy
D. larger than its input

26.  When power output of an amplifier doubles, the increase in its power level is ? decibels

27. When output power level of a radio receiver increases by 3 dB, its absolute power changes by a factor of
C. 1/2

28. The main reason for the variation of amplifier gain with frequency is
A. the presence of capacitances, both external and internal
B. due to interstage transformers
C. the logarithmic increase in its output power
D. the Miller effect

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