Electronics and Communication Engineering - Analog Electronics

21. 

In the amplifier circuit of figure hfe = 100 and hie = 1000 Ω. The voltage gain of amplifier is about

A. 0.33
B. 0.5
C. 0.66
D. 1

Answer: Option D

Explanation:

.


22. 

The efficiency of a full wave rectifier using centre tapped transformer is twice that in full wave bridge rectifier.

A. True
B. False

Answer: Option B

Explanation:

Efficiency of full wave rectifier with centre tapped transformer is slightly higher than that of bridge rectifier.


23. 

Assertion (A): CE amplifier is the most widely used BJT amplifier

Reason (R): CE amplifier has zero phase difference between input and output

A. Both A and R are correct and R is correct explanation for A
B. Both A and R are correct but R is not correct explanation for A
C. A is correct R is wrong
D. A is wrong R is correct

Answer: Option C

Explanation:

There is 180° phase difference between input and output.


24. 

Assertion (A): For large signal variations an amplifier circuit has to be analysed graphically

Reason (R): The output characteristics of a transistor is nonlinear.

A. Both A and R are correct and R is correct explanation for A
B. Both A and R are correct but R is not correct explanation for A
C. A is correct R is wrong
D. A is wrong R is correct

Answer: Option A

Explanation:

Since the characteristics is non-linear, graphical analysis is needed.


25. 

Negative feedback reduces noise originating at the amplifier input.

A. True
B. False

Answer: Option B

Explanation:

It has no effect on noise originating at amplifier input.