EC2205 ELECTRONIC CIRCUITS - I ANNA UNIVERSITY PREVIOUS YEAR QUESTION PAPER APRIL/MAY 2010 FOR ECE DEPARTMENT ...

B.E./B.Tech. DEGREE EXAMINATION, APRIL/MAY 2010

Third Semester

Electronics and Communication Engineering

EC2205 â€" ELECTRONIC CIRCUITS â€" I

(Regulation 2008)

Time: Three hours Maximum: 100 Marks

Answer ALL Questions

PART A â€" (10 × 2 = 20 Marks)

1. Define stability factor.
2. Calculate the value of feedback resistor (Rs) required to self bias an N-channel
JFET with IDSS = 40 mA, Vp = -10 v and VGSQ = -5V.
3. Define Miller's theorem.
4. What is the coupling schemes used in multistage amplifiers?
5. Give the expressions for gain bandwidth product for voltage and current.
6. What do you mean by amplifier rise time?
7. What is cross over distortion?
8. Draw the circuit of Class-D amplifier.
9. Compare the half-wave and full-wave rectifiers.
10. What are the advantages of SMPS?

PART B â€" (5 × 16 = 80 Marks)

11. (a) (i) Explain the fixed bias method and derive an expression for the
stability factor. (8)
(ii) Explain the voltage divider bias method and derive an expression
for the stability factor. (8)
Or
(b) (i) Explain the circuit which uses a diode to compensate for changes in
VBE and in ICO. (12)
(ii) Discuss the operation of thermistor compensation. (4)
12. (a) (i) Derive the expressions for the following of a small signal transistor
amplifier in terms of the h-parameters
(1) current gain
(2) voltage gain
(3) input impedance
(4) output admittance. (12)
(ii) Compare CB, CE and CC amplifiers. (4)
Or
(b) (i) Explain the operation of emitter coupled differential amplifier. (12)
(ii) Discuss the transfer characteristics of the differential amplifier. (4)
13. (a) Discuss the low frequency response and the high frequency response of
an amplifier. (16)
Or
(b) Explain the operation of high frequency common source FET amplifier
with neat diagram. Derive the expression for (i) voltage gain (ii) input
admittance (iii) input capacitance (iv) output admittance. (16)
14. (a) (i) Explain the operation of the transformer coupled class A audio
power amplifier. (12)
(ii) Explain the term s conversion efficiency and maximum value of
efficiency used in audio power amplifiers. (4)
Or
(b) Explain the operation of the class-B push pull power amplifier with neat
diagram and list its advantages. (16)
15. (a) Derive the expressions for the rectification efficiency, ripple factor,
transformer utilization factor, form factor and peak factor of
(i) half wave rectifier
(ii) full wave rectifier. (16)
Or
(b) Explain the operation of
(i) Voltage multiplier (8)
(ii) Switched mode power supply. (8)