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

equivalent circuits? [16]
7. (a) What is Voltage regulator? discuss with the help of neat circuit diagram how
zener diode is used as a shunt voltage regulator?
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Code No: R059210404 Set No. 3
(b) In figure seven shown Vi=20V, Rs=200 ohms and Vz=12V, VBE =0.65V obtain
output voltage, collector to emitter voltage of the transistor and the current
in 200 ohms resistor? [8+8]
Figure 7
8. (a) Draw and discuss the output of pulse width modulator for various kinds of
inputs with respect to switching regulator.
(b) Draw the circuit and discuss the operation of basic switching kind regulator.
[8+8]
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Code No: R059210404 Set No. 4
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) Draw the circuit diagram of CB- amplifier and its h-parameter equivalent
circuit. List out the characteristics of a CB amplifier.
(b) In a single stage CB amplifier circuit, RE = 20K,RC = 10K, VEE = -20V, VCC =
20V,RL = 10KandRS = 0.5K. obtain AI ,Ri,Ro,AV . (8+8)
2. (a) How multistage amplifiers are classified depending upon the kind of coupling.
(b) Write a note on distortions in amplifiers.
(c) In an R-C coupled amplifier, AVM = 60, fL = 50Hz and fH=100KHz. obtain
the values of frequencies at which the gain decreases to 50 on either side of mid
band region. [4+6+6]
3. (a) elaborate the typical values of different components in Hybrid - p model? Show
that at low frequencies the Hybrid - p model with rb'e and rce taken as infinite
decreases to the approximate CE h- parameter model.
(b) The subsequent low- frequency parameters are known for a provided transistor at
IC = 10mA, VCE =10 V, and at room temperature,
hie = 500

hoe = 4x10-5 A/V
hfe = 100
hre = 10-4.
At the identical operating point, fT = 50MHz and Cc=3PF, calculate the values
of all the Hybrid - p parameters [8+8]
4. (a) describe thermal resistance of a power BJT.
(b) A transistor with a maximum junction temperature specification of 1500C
dissipates a maximum power of 40 watts at a case temperature of 250C and 2
watts at an ambient temperature of 250C. obtain
i. The thermal resistance ranging from the junction and the case.
ii. The thermal resistance ranging from the junction and ambient.
iii. Maximum power dissipation capability for safe operation in free space at
a temperature of 500C. [4+4x3]
5. (a) What is meant by the term Tuned amplifier and briefly discuss the different
methods of classification of tuned amplifiers?
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Code No: R059210404 Set No. 4
(b) A constant generator drives a parallel tuned circuit consisting of a loss less
capacitor ‘C’ and a coil ‘L’ (having small resistance ‘R’). Derive the expression
for the frequency of resonance? [8+8]
6. (a) discuss the principle of a wideband amplifier?
(b) Derive the expression for Optimum value of collector circuit resistor (RC, opt)
of 1 stage of a CE cascade amplifier. Draw the graph showing the variation
of Bandwidth, Gain and Gain bandwidth product as a function of RC and
write the comments from the graph to improve the bandwidth. [4+12]
7. (a) With the help of a neat circuit diagram, discuss the operation of BJT shunt
voltage regulator.
(b) What is a voltage reference? Why is it needed?
(c) What is the function of a series pass transistor? [8+4+4]
8. (a) discuss how 3 terminal IC 7805 is used as a current source with a neat
circuit diagram. [8]
(b) What is a Voltage multiplier? Draw and discuss any 1 circuit of it and provide
its applications. [8]
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Earning:   Approval pending.