Cochin University of Science and Techology (CUST) 2006 B.Tech Electronics and Communications Engineering electronic circuits - Question Paper

B.Tech. Degree lV Semester exam May 2006
ELECTRONIC CIRCUIT
Max marks 100



1.a) What is the need for biasing? discuss the concept of load line with necessary
diagrams.

b) Draw the simplified h-parameters model of a CE amplifier and derive the
expressions for 1.input impedance
2. output impedance
3. voltage gain
4. current gain

OR

2. a) Draw the circuit of an RC coupled amplifier and discuss its frequency response.
Derive expression for lower cut off frequency.

b) What is an emitter follower? provide its applications.

3. a) Derive the expression for voltage gain of a RC coupled common source FET
amplifier.

b) discuss how an FET can be used on a voltage variable resistor

OR

4. a) discuss the 4 various kinds of negative feedbacks in amplifiers. elaborate the
advantages of negative feedback?

b) Compare B.J.T with FET.

5. a) explain about Class-B power amplifiers. obtain out its efficiency.

b) What is meant by cross over distortion? How this can be reduced?

OR

6. a) What is Barkhausen criterion? discuss with circuit diagram, the working of a
Hartley oscillator. Write the expression for frequency of oscillation.

b) discuss “thermal run away” in transistor. How the heat generated in transistors can
be removed.

7. a) discuss a RC integrated circuit. Derive the design formula for the integrator.

b) elaborate clippers? provided a sine wave with 10V p-p. Draw a circuit which can clip
this signal at +2V and -3V at positive and negative half cycles respectively.
discuss its working.

OR

8. a) Draw the circuit and discuss the working of a stable multivibrators, using
transistors with necessary waveforms.

b) discuss the operation of a UJT relaxation oscillator. Draw necessary diagrams.
provide its applications.

9. a) discuss single tuned, double tuned and stagger tuned amplifiers, with necessary
sketches.

b) explain about wide band amplifiers. discuss gain bandwidth trade off.

10. a) Write short notes on 1. tuned amplifiers and Q-factor
2. cascade amplifier
3. unilateralisation of transistor
4. low frequency RC compensation.


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Earning:   Approval pending.