# Electronic Circuits I 3rd AM10 EC2205

B.E./B.Tech. DEGREE EXAMINATION, APRIL/MAY 2010
Third Semester
Electronics and Communication Engineering
EC2205 - ELECTRONIC CIRCUITS - I
(Regulation 2008)

Programming Questions  |  Travel Tips | Mobile Review | Placement Papers

ANNA UNIVERSITY PAPERS:

PART A — (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 — (5 × 16 = 80 Marks)

11. (a) (i) Explain the fixed bias method and derive an expression for the stability factor. (Marks 8)
(ii) Explain the voltage divider bias method and derive an expression for the stability factor. (Marks 8)
Or
(b) (i) Explain the circuit which uses a diode to compensate for changes in VBE and in ICO. (Marks 12)
(ii) Discuss the operation of thermistor compensation. (Marks 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
(ii) Compare CB, CE and CC amplifiers. (Marks 4)
Or
(b) (i) Explain the operation of emitter coupled differential amplifier. (Marks 12)
(ii) Discuss the transfer characteristics of the differential amplifier. (Marks 4)

13. (a) Discuss the low frequency response and the high frequency response of an amplifier. (Marks 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. (Marks 16)

14. (a) (i) Explain the operation of the transformer coupled class A audio power amplifier. (Marks 12)
(ii) Explain the terms conversion efficiency and maximum value of efficiency used in audio power amplifiers. (Marks 4)
Or
(b) Explain the operation of the class-B push pull power amplifier with neat diagram and list its advantages. (Marks 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. (Marks 16)
Or
(b) Explain the operation of
(i) Voltage multiplier (Marks 8)
(ii) Switched mode power supply. (Marks 8)