BJT Amplifiers and Oscillators MCQs

Question 1

A large sacrifice factor in a negative feed-back amplifier leads to

Accepted Answer

characteristics impossible to achieve without feed-back

Answer

precise control over output

Answer

inferior performance

Answer

increased output impedance

Question 2

Which of the following is the most desirable feature of transformer coupling?

Accepted Answer

Ability to provide impedance matching between stages

Answer

Higher voltage gain

Answer

Wide frequency range

Answer

None of the above

Question 3

A D.C. amplifier amplifies

Accepted Answer

both D.C. and A.C.

Answer

D.C. only

Answer

A.C. only

Answer

none of the above

Question 4

For sustaining oscillations in a feedback amplifier, the loop gain should be

Accepted Answer

greater than one (d) none of the above

Answer

zero

Answer

less than one

Question 5

Which of the following stagements is incorrect regarding differential amplifier?

Accepted Answer

It is not much used in ICs

Answer

It is used to eliminate noise packed up along a short transmission line

Answer

It has the ability to amplify the difference between two signals

Answer

Its output is taken from the collectors of the two transistors

Question 6

Cascaded amplifiers which find wide use in ICs are

Accepted Answer

direct coupled

Answer

transformer coupled

Answer

inductively coupled

Answer

capacitively coupled

Question 7

A two-transistor Class-B amplifier is usually called

Accepted Answer

push-pull amplifier

Answer

dual amplifier

Answer

inverting amplifier

Answer

symmetrical amplifier

Question 8

To avoid a high noise figure in an amplifier, the volume control should

Accepted Answer

not have large D.C. current flowing through it

Answer

be much less than base resistance

Answer

have a value less than 5 kg2

Answer

have a value greater than 5 ki2

Question 9

Johnson noise in an amplifier is the noise produced due to

Accepted Answer

the fact that electrons in a resistor carry slightly different amounts of energy

Answer

lighting

Answer

the fact that the current is carried by discrete particles

Answer

switching off or on of an electrical apparatus