Electronics and Communication Engineering - Analog Electronics

26. 

Maximum efficiency of class B power amplifier is 50%.

A. True
B. False

Answer: Option B

Explanation:

Maximum efficiency for class B-operation can be 78.5% .


27. 

In figure what is the base current if VBE = 0.7 V

A. 10 mA
B. 9.3 mA
C. 10 μA
D. 9.3 μA

Answer: Option D

Explanation:

.


28. 

In figure ID = 4 mA. Then VS =

A. 20 V
B. 4.4 V
C. 0.4 V
D. 0.44 V

Answer: Option B

Explanation:

VS = ISRS = 4 x 10-3 x 1.1 x 103 = 4.4 V.


29. 

The self bias provides

A. stable Q point
B. large voltage gain
C. high input impedance
D. high base current

Answer: Option A

Explanation:

Stable Q point is the advantage of self bias circuit.


30. 

In figure what is value of IC if βdc = 100. Neglect VBE

A. 5 mA
B. 5 μA
C. 10 mA
D. 10 μA

Answer: Option C

Explanation:

Since IB = 100 μA, IC = βIB = 10 mA.