Deck 31: Transistor Amplifiers

Question 1

Because the output signal follows the input signal, the common-collector amplifier is usually referred to as a(n) ______________ follower.

Answer 1

emitter

Question 2

The emitter follower has a high input impedance and a low output impedance which makes it ideal for impedance ______________ applications.

Answer 2

matching

Question 3

With the ______________-collector configuration, the input signal and output signal are in phase with each other.

Answer 3

common

Question 4

The main purpose of the emitter follower is to ______________ the relatively low value of load resistance from the high impedance collector.

Question 5

The common-base amplifier provides a high voltage and power gain, but the current gain is ______________ 1.

Question 6

With the CB amplifier, the output is taken from the ______________.

Question 7

______________ amplifiers are often used in high frequency equipment.

Question 8

The biasing of a transistor deals specifically with ______________ voltages and currents.

Question 9

When analyzing a common-emitter amplifier, it is common practice to represent the emitter diode as a small ______________.

Question 10

The ratio of an ac collector current to ac base current is called the ac ______________.

Question 11

The common-collector amplifier is usually referred to as a

A) common amplifier
B) collector follower
C) emitter follower
D) collector amplifier

Question 12

The common-collector has a

A) high input impedance and high output impedance
B) low input impedance and low output impedance
C) high input impedance and low output impedance
D) low input impedance and high output impedance

Question 13

Which transistor amplifier configuration offers effective impedance matching?

A) Common-base
B) Common-collector
C) Common-emitter
D) Base follower

Question 14

The output of an emitter follower is taken from the

A) base
B) collector
C) emitter
D) voltage source

Question 15

The phase shift between the input signal and the output signal of a CC amplifier is

A) 0°
B) 45°
C) 180°
D) 270°

Question 16

In most cases, the emitter follower does not use biasing resistors because the

A) emitter follower does not need a Q point
B) capacitors are used instead
C) stage driving the emitter follower provides the required dc bias
D) resistors cause distortion

Question 17

The output impedance of an emitter follower is usually

A) very high
B) very low
C) equal to R_E
D) equal to R_C

Question 18

The voltage gain of an emitter follower is approximately

A) 0
B) 1
C) 3
D) 10

Question 19

When the emitter follower is used to isolate a low value of load resistance from the high impedance collector, the emitter follower serves as a(n)

A) bridge circuit
B) amplifier
C) coupler
D) buffer

Question 20

Which transistor configuration provides a high voltage and power gain, but a current gain of less than one?

A) Common-base
B) Common-emitter
C) Common-collector
D) Base follower

Question 21

Which transistor configuration provides some desirable features for operation at higher frequencies?

A) Common-base
B) Common-emitter
C) Common-collector
D) Base follower

Question 22

In the ac analysis of a common-base amplifier, all coupling capacitors are treated as

A) ac opens
B) dc shorts
C) ac shorts
D) diodes

Question 23

Which transistor configuration has the best high frequency response and also has a low input impedance that approximates the 50 ? rf-circuitry antennas?

A) Common-base
B) Common-emitter
C) Common-collector
D) Base follower

Question 24

What is the input-output phase relationship of the common-base configuration?

A) In phase
B) Out of phase by 45°
C) Out of phase by 90°
D) Out of phase by 180°

Question 25

The purpose of the dc bias is to

A) set the gain of the amplifier
B) couple the ac signals from stage to stage
C) establish the desired operating point
D) determine the amplifier's input impedance

Question 26

A signal that has a peak-to-peak current equal to or less than one-tenth of the dc diode current is typically referred to as

A) microwave
B) small signal
C) medium signal
D) miniature signal

Question 27

When analyzing a common-emitter amplifier, it is common practice to represent the emitter diode as a(n)

A) open circuit
B) large resistance
C) small resistance
D) small capacitance

Question 28

In the CE configuration, what provides a low-impedance path for ac signals between the emitter terminal and ground?

A) Input coupling capacitor
B) Emitter resistor
C) Base-emitter junction
D) Emitter bypass capacitor

Question 29

The phase shift between v_in and v_out for a common-emitter amplifier is

A) 0°
B) 45°
C) 90°
D) 180°

Question 30

One way to significantly reduce the variations in the CE A_V caused by changes in equivalent ac resistance is to add a(n)

A) emitter bypass capacitor
B) another amplifier stage
C) swamping resistor in the emitter circuit
D) larger coupling capacitor

Question 31

One way to significantly reduce distortion in a CE amplifier is to add a(n)

A) emitter bypass capacitor
B) another amplifier stage
C) swamping resistor in the emitter circuit
D) larger coupling capacitor

Question 32

Which transistor configuration provides current and power gain, but provides a voltage gain of approximately one?

A) Common-base
B) Common-emitter
C) Common-collector
D) Base follower

Question 33

The biasing of a transistor deals specifically with ac voltages and currents.

Question 34

The purpose of the dc bias is to establish the desired Q point.

Question 35

The input signal applied to a linear amplifier should be large enough to shift the instantaneous operating point to either saturation or cutoff.

Question 36

Small signal is generally meant to be a signal that has a peak-to-peak current equal to or less than one-tenth the dc diode current.

Question 37

When analyzing a common-emitter amplifier, it is common practice to represent the emitter diode as a small resistance.

Question 38

An emitter bypass capacitor provides a low-impedance path for dc signals between the emitter terminal and ground.

Question 39

The ratio of ac collector current to ac base current is called the dc beta.

Question 40

The common-emitter amplifier is the only transistor amplifier configuration that produces a 180° phase shift between v_in and v_out.

Question 41

The power gain of a CE amplifier equals A_V times A_i.

Question 42

One way to significantly reduce the variations in A_V caused by changes in equivalent ac resistance is to add a swamping resistor in the emitter circuit.

Question 43

Adding a swamping resistor to the emitter circuit increases distortion considerably.

Question 44

Any impedance in the emitter circuit of a CE amplifier appears greater by a factor of beta when viewed from the base.

Question 45

The input impedance of an amplifier is the input impedance seen by the ac source driving the amplifier.

Question 46

The output impedance of a CE amplifier equals the value of the collector resistor, but does not include the load resistor.

Question 47

The common-collector amplifier is used to provide current gain and power gain.