Electronics and Communication Engineering - Analog Electronics

41. 

An exponential amplifier has diode in feedback path.

A. True
B. False

Answer: Option B

Explanation:

It has resistance in feedback path.


42. 

DC amplifiers have a tendency to be unstable.

A. True
B. False

Answer: Option A

Explanation:

Due to drift.


43. 

A half wave diode rectifier has a capacitance input filter. If input voltage is Vm sin ωt, PIV is

A. Vm
B. 2 Vm
C. 3 Vm
D. 4 Vm

Answer: Option B

Explanation:

Because capacitor charge is retained.


44. 

An amplifier with loop gain Aβ will be more stable for value of Aβ as

A. 0.95
B. 0.7
C. 1.2
D. 1.5

Answer: Option B

Explanation:

A feedback amplifier is stable if loop gain is less than unity. More less, more stable, hence β will be more stable.


45. 

Study the circuit of figure and examine the following statements

  1. It is an active low pass finer.
  2. It is a second order filter.
  3. The change in gain is 40 dB/decade.
Which of the above statements are correct?

A. 1, 2 and 3
B. 1 and 2
C. 1 and 3
D. 2 and 3

Answer: Option A

Explanation:

The circuit is a second order active low pass filter for which gain is 40 dB/decade.