Electronics and Communication Engineering - Analog Electronics

21. 

A negative feedback can be of

A. 2 types
B. 3 types
C. 4 types
D. only 1 type

Answer: Option C

Explanation:

Series voltage, series current, shunt voltage and shunt current.


22. 

In a class C power amplifier the input frequency of ac signal is 1 MHz. If tank circuit has C = 1000 pF, the value of L =

A. 25 μH
B. 50 μH
C. 100 μH
D. 200 μH

Answer: Option A

Explanation:


23. 

The Vo of the op-amp circuit shown in the given is

A. 11 Vi
B. 10 Vi
C. Vi
D. zero

Answer: Option D

Explanation:

V0 = (Vs2 - Vs1)

[Vs1 - Vs1] = 0.


24. 

In calculating output impedance of an amplifier the source is replaced by an open circuit.

A. True
B. False

Answer: Option B

Explanation:

It is replaced by short circuit.


25. 

For transistor 2 N 338 the manufacturer specifies Pmax = 100 mW at 250°C free air temperature and maximum junction temperature of 125°C. Its thermal resistance is

A. 10° C/W
B. 100° C/W
C. 1000° C/W
D. 5000° C/W

Answer: Option C

Explanation:

.