BJT Amplifiers and Oscillators MCQs

Question 1

A resistive attenuator was fed from a source of 12 V giving an output of 6 V. If output and input resistances are the same, the gain in decibels is

Accepted Answer

-3 dB

Answer

indeterminate

Answer

3 dB

Answer

-2 dB

Question 2

1-dB bandwidth of an amplifier is isiwasy greater than the total bandwidth. Is it true?

Accepted Answer

No, not at all

Answer

Yes, it is

Answer

Sometimes, it may be like that

Answer

none of these

Question 3

3 dB points are nothing but

Accepted Answer

the points where the voltage is 0.707 times the maximum

Answer

the points where the power is 0.707 x 'max

Answer

the points where the voltage is j times the average value

Answer

none of these

Question 4

A square wave signal was applied to an amplifier with a poor low frequency response. The output waveform had

Accepted Answer

distorted flat-top portion

Answer

distorted vertical edges

Answer

not suffered any distortion

Answer

been converted into a triangular waveform

Question 5

A squarewave signal was applied to an amplifier with a very good low frequency response but a very poor high frequency response. The output waveform had

Accepted Answer

suffered severe distortion along vertical edges with fairly good flat region

Answer

suffered severe distortion throughout

Answer

suffered severe distortion of flat region with fairly good reproduction of vertical edges

Answer

none of these

Question 6

It is not possible to use zero watt as zero dB reference level because

Accepted Answer

it results in a power gain of infinity

Answer

log 0 = ?oc

Answer

log 0. =

Answer

none of these

Question 7

A noiseless amplifier's noise figure is

Accepted Answer

0 dB.

Answer

1 dB

Answer

none of these

Question 8

Bass and treble controls

Accepted Answer

alter low and high frequency response of the amplifier

Answer

alter the low frequency response of the amplifier

Answer

alter the high frequency response of the amplifier

Answer

none of these

Question 9

One bel equals

Accepted Answer

a power ratio of 10

Answer

1 dB

Answer

100 dB

Answer

a power ratio of 100