In an oscillator, the resonant feedback circuit must have must have a low Q in order to achieve stable oscillation.

Assertion (A): A linear, negative feedback control system is invariable stable if its open loop configuration is stable Reason (R): the negative feedback reduces the overall gain of the feedback.

A

Both A and R are true and R is correct explanation of A

B

Both A and R are true and R is not correct Explanation of A

C

A is True and R is false

D

A is False and R is true

Consider the following statements with respect to the feedback of the control systems. i. Feedback can improve stability or be harmful to stability if it is not properly applied. ii. Feedback can always improve stability iii. In many situations the feedback can reduce the effect of noise and disturbance on system performance. iv. In general the sensitivity of the system gain of a feedback system of a parameter variation depends on where the parameter is located.

A

i, ii, iii and iv only

B

i, ii and iii only

C

i, iii and iv only

D

i, ii and iv only

Consider the following statements with respect to the feedback of the control systems: 1. Feedback can improve stability or be harmful to stability if it is not properly applied. 2. Feedback can always improve stability 3. In many situations the feedback can reduce the effect of noise and disturbance on system performance. 4. In general the sensitivity of the system gain of a feedback system of a parameter variation depends on where the parameter is located.

A

1,2 and 3 only

B

1,3 and 4 only

C

1,2 and 4 only

D

1,2,3 and 4 only

The tank circuit of a Hartley oscillator is shown in the figure. If M is the mutual inductance between the inductors, the oscillation frequency is
Electronics mcq question image

A

$$\frac{1}{{2\pi \sqrt {\left( {{L_1} + {L_2} + 2M} \right)C} }}$$

B

$$\frac{1}{{2\pi \sqrt {\left( {{L_1} + {L_2} - 2M} \right)C} }}$$

C

$$\frac{1}{{2\pi \sqrt {\left( {{L_1} + {L_2} + M} \right)C} }}$$

D

$$\frac{1}{{2\pi \sqrt {\left( {{L_1} + {L_2} - M} \right)C} }}$$

Colpitts oscillator in the feedback section has an inductance of 4 mH and capacitors of 12 nH and 4 nH. Then the resonant frequency of Colpitts oscillator is:

A

50.4 kHz

B

35.1 kHz

C

45.9 kHz

D

None of the mentioned

If the input impedance of a diode used in the microwave oscillator is 45-j23 Ω, then the load impedance is to achieve stable oscillation is:

A

45-j23 Ω

B

-45+j23 Ω

C

50 Ω

D

23-j45 Ω

To achieve stable oscillation, Zin + ZL=0 is the only necessary and sufficient condition to be satisfied by the microwave oscillator.

A

True

B

False

In an oscillator if phase of feedback is same as that of oscillation waveform then feedback is called ___________

A

Positive feedback

B

Negative feedback

C

Cannot be predicted

D

Either positive or negative depending upon frequency

Consider the circuit shown below. Consider A: Current-shunt feedback B: Current-series feedback C: Voltage-shunt feedback D: Voltage-series feedback Which of the above are present?

A

A and B

B

A only

C

B only

D

A and D

Consider the following statements.
A Simple Pendulum is set into oscillation. Then,
1. the acceleration is zero when the bob passes through the mean position.
2. in each cycle the bob attains a given velocity twice.
3. both acceleration and velocity of the bob are zero when it reaches its extreme position during the oscillation.
4. the amplitude of oscillation of the simple pendulum decreases with time.
Which of these statements are correct?

A

Only 1 and 2

B

Only 3 and 4

C

Only 1, 2 and 4

D

Only 2, 3 and 4

In an oscillator, the resonant feedback circuit must have must have a low Q in order to achieve stable oscillation.

Related Questions