CLASSES

Question 1

most common type of amplifier topology

Answer 1

Class A

Question 2

biased around the Q-point within the middle of its load line

Answer 2

Class A

Question 3

conduct current over the full 360 degrees of the input cycle

Answer 3

Class A

Question 4

one of the main disadvantages of Class A

Answer 4

output transistor of a class-A topology never turns “OFF”

Question 5

excellent linearity, high gain and low signal distortion levels

Answer 5

Class A

Question 6

create tremendous amounts of heat adding to their very low efficiency at around 30%, making them impractical for high-power amplifications

Answer 6

Class A

Question 7

invented as a solution to the efficiency and heating problems

Answer 7

Class B

Question 8

uses two complimentary transistors either bipolar of FET (“push-pull” type arrangement)

Answer 8

Class B

Question 9

transistor device amplifies only half of the output waveform

Answer 9

Class B

Question 10

there is no DC base bias current as its quiescent current is zero, so that the dc power is small and therefore its efficiency is much higher

Answer 10

Class B

Question 11

This push-pull design of amplifier is obviously more efficient than Class A, at about 50%

Answer 11

Class B

Question 12

combination of the “Class A” and the “Class B”

Answer 12

Class AB

Question 13

both devices (T1&T2) are allowed to conduct at the same time around the waveforms
crossover point eliminating the crossover distortion problems

Answer 13

Class AB

Question 14

two transistors have a very small bias voltage, typically at 5 to 10% of the
quiescent current to bias the transistors just above its cut-off point.

Answer 14

Class AB

Question 15

efficiencies reach about 50% to 60%

Answer 15

Class AB

Question 16

has the greatest efficiency but the poorest linearity

Answer 16

Class C

Question 17

is heavily biased so that the output current is zero for more than one half of an input sinusoidal signal cycle with the transistor idling at its cut-off point.

Answer 17

Class C

Question 18

the conduction angle for the transistor is significantly less than 180 degrees, and is
generally around the 90 degrees area.

Answer 18

Class C

Question 19

much improved efficiency of around 80% to the amplifier, it introduces a very heavy
distortion of the output signal.

Answer 19

Class C

Question 20

not suitable for use as audio amplifiers.

Answer 20

Class C

Question 21

non-linear switching amplifier or PWM amplifier

Answer 21

Class D

Question 22

boost both efficiency and output by using harmonic resonators in the output network to shape the output waveform into a square wave.

Answer 22

Class F

Question 23

uses multiple power supply rails of various voltages and automatically switches between
these supply rails as the input signal changes

Answer 23

Class G

Question 24

has two sets of complementary output switching devices arranged in a type of parallel push-pull configuration (one device switches the positive half of the waveform, while the other switches the negative half)

Answer 24

Class I