Jawaharlal Nehru Technological University Kakinada 2007 B.Tech Electronics and Communications Engineering ELECTRONIC CIRCUIT ANALYSIS - Question Paper

II B.Tech I Semester Regular Examinations, November 2007
ELECTRONIC CIRCUIT ANALYSIS
( Common to Electronics & Communication Engineering and Electronics &
Telematics)
Time: three hours Max Marks: 80
ans any 5 ques.
All ques. carry equal marks
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1. (a) With the help of necessary equations, explain the variation of AI ,AV ,Ri, and
Ro with RS and RL in Common Emitter configuration.
(b) For a CE configuration, what is the maximum value of RS for which Ro differs
by no more than 10 percent of its value for RS = 0. The h-parameter values
are hfe = 50, hie =1.1K
, hre = 2.5x10-4, hoe = 25 µA/V. [10+6]
2. A two-stage amplifier circuit (CE-CC configuration) is shown in figure 2. The h-
parameter values are hfe = 50, hie=2 K
, hre =6× 10-4, hoe = 25µA/V.
hfc = -51, hic =2 K
, hrc = 1, hoc = 25µ A/V.
obtain the input and output impedances and individual, as well as overall voltage
and current gains.
Figure 2
3. (a) Draw Hybrid - p model for a transistor in the CE configuration and discuss
the significance of every component in this model.
(b) provided a germanium p-n-p transistor whose basewidth is 10-4 cm. At room
temperature and for a dc emitter current of two mA, obtain
i. emitter diffusion capacitance,
ii. fT [Assume Diffusion constant as 47 cm2/sec]. [8+8]
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Code No: R059210404 Set No. 1
4. (a) In series fed Class - A power amplifier, discuss the importance of the position
of operating point on output signal swing. Show that the conversion efficiency
is 25%.
(b) explain the origin of different distortions in transistor amplifier circuits. [10+6]
5. Draw the circuit diagram of a Double tuned amplifier and derive the expression for
3-dB bandwidth. [16]
6. discuss the reasons for oscillations in a tuned amplifier. Briefly discuss the methods
used to stabilize the tuned amplifiers against oscillations? [16]
7. (a) discuss why voltage regulators are called as closed loop control systems?
(b) A power Supply having output resistance of two ohms supplies a full-load current
of 100mA to a 50 ohms load. obtain the percent voltage regulation and no-load
output voltage of the supply?
(c) Draw and discuss the load voltage and load current characteristic for a current
limited regulator. [4+6+6]
8. (a) What is catcher diode and discuss the necessity of catches diode in Switch
Regulator with the help of circuit diagram.
(b) List the operating ratings and electrical characteristics of IC 723. [8+8]
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2 of 2
Code No: R059210404 Set No. 2
II B.Tech I Semester Regular Examinations, November 2007

Earning:   Approval pending.