EC 1261 — ELECTRONIC CIRCUITS

By kalu -

B.E./B.Tech. DEGREE EXAMINATION, APRIL/MAY 2008.

Third Semester

Electronics and Instrumentation Engineering

EC 1261 — ELECTRONIC CIRCUITS

¤Common to Instrumentation and Control Engineering)

(Regulation 2004)

Time : Three hours

Maximum : 100 marks.

Answer ALL questions.

PARTA — 10 x 2 = 20 marks

1. Draw the fixed and self bi ¤s mi ;uit of BJT.

2. Draw the h-parameter eqiivalent circuit of a Common—emitter transistor.

3. What is CMRR

4. Draw a tuiresl circuit.

5. Define feedback factor.

6. What are the conditions of oscillation in sinusoidal oscillators.

7. What is time constant in a RC circuit?

8. What is a clipper?

9. Define peak inverse voltage of a rectifier.

10. Draw the functional block diagram of SMPS.

PART B -— (5 x 16 : 80 marks)

A11.

(a) (i) Derive the expressions for the input resistance, voltage gain,current gain, and output admittance of a transistor amplifier interms of h-parameters. (8)

(ii) Explain about Cascode and Darlington connections. (8)

Or

(b) (i) Explain the operation of the transformer coupled power amplifier.(8)

(ii) Explain the operation of the Class—B push pull power amplifier. (8)

12. (a) Explain in detail about the operation of the Emiter coupled differentialamplifier.

Or

(b) Explain the operation ofthe single and double tuned amplifiers,

13. (a) With topologies compare the periormancc of voltage/current of the seriesI and shunt feedback ampiiinis.

Or

(b) Explain the operation of the Weiirbridge oscillators. What are theadvantages oi crystal oscillators?

14. (a) (i) Explain with circuit diagram and waveforms positive and negativeClamper circuits. (8)(ii) Explain the operation of a UJT saw tooth oscillator. (8)

Or

(b) Explain the operation of a monostable multivibrator circuit.

15. (a) Explain in detail about the operation ofthe Half wave rectifier, full waverectifier and Bridge rectifiers.

Or

(b) (i) Compare the ripple factor for the inductor filter and capacitor filter,(4)

(ii) Explain the operation of the series voltage regulators. (12)

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