Operational Amplifier and Its Applications MCQs

Question 1

According to Barkhausen Criterion, for oscillations to occur

Accepted Answer

loop gain 1 and loop phase shift =0

Answer

loop gain 1 and loop phase shift = 1800

Answer

loop gain 5 1 and loop phase shift =0

Answer

loop gain 5 1 loop phase shift = 1800

Question 2

According to Barkhausen criterion, loop gain should at least be unity for maintenance of oscillations but loop gain is kept generally greater than one Why?

Accepted Answer

so that oscillator functions quite alright even after circuit parameters have changed a bit resulting in a reduction of loop gain.

Answer

because oscillations gradually die down if loop gain is precisely unity

Answer

because to initiate oscillations, it has to be greater than unity

Answer

none of these

Question 3

Most commonly employed type of oscillator for audio applications is

Accepted Answer

the R?C oscillator

Answer

the L?C oscillator

Answer

the crystal oscillator

Answer

none of these

Question 4

Oscillator type that is preferred in radio frequency region is the

Accepted Answer

resonant circuit oscillator

Answer

R?C oscillator

Answer

crystal oscillator

Answer

none of these

Question 5

One particular type of L?C oscillators is having a tapped coil in the feedback network. It is

Accepted Answer

Hartley oscillator

Answer

Colpitt's oscillator

Answer

clap's oscillator

Answer

none of these

Question 6

One particular type of oscillator is having a spilt capacitor in the feedback path. It is

Accepted Answer

Colpitt's oscillator

Answer

Hartley oscillator

Answer

Clap's oscillator

Answer

none of these

Question 7

Why are R?C oscillators unsuitable for radio-frequency applications?

Accepted Answer

At higher radio frequencies capacitors required have nonpractical values

Answer

Resistor and capacitors get heated up at higher frequencies

Answer

Resistors cause tremendous power loss at higher frequencies

Answer

none of these

Question 8

One of the following oscillator types in used for extremely stable output frequency

Accepted Answer

Resistance?capacitance oscillators

Answer

Resonant circuit oscillators

Answer

Weinbridge oscillators

Answer

Crystal oscillators

Question 9

One of the following electronic systems is an example of D.C. to A.C. conversion

Accepted Answer

Oscillators

Answer

Electronic rectifier

Answer

Electronic converter

Answer

Amplifiers