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Reg. No. : .................................... Name : .........................................

Third Semester B.Tech. Degree Examination, November 2009 (2003 Scheme) 03-304 : ELECTRONIC CIRCUITS (RF) Time : 3 Hours

Max. Marks : 100 PART – A

Answer all questions. Each question carries 4 marks. 1. What is meant by stabilization ? Explain thermal instability. 2. Prove that the regulation of half wave rectifier is given by % regulation =

RF × 100 . RL

3. Show that a low pass circuit with a large time constant acts as an integrator. 4. What do you mean by a two way clamp ? 5. Write three most important characteristics of an emitter follower. 6. An operational amplifier has a slew rate of 35 V / μs . How long will it take the output to change from 0 to 15 V ? 7. Briefly explain the difference between the two operating modes of the 555 timer. 8. Draw the circuit of a Domino logic AND gate. 9. How are capacitors manufactured in various IC technologies ? 10. Explain ‘sheet resistance’ and ‘ohms per square’.

(10×4=40 Marks)

P.T.O.

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PART – B Answer one full question from each Module. Each question carries 20 marks. Module – I 11. a) Draw the transfer characteristics for the circuit shown. Also draw the output waveform for a sinusoidal input of amplitude 20 V.

b) Derive an expression for the lower cutoff frequency of a high pass circuit.

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OR 12. a) A step generator of 50 Ω impedance applies a 10 V step of 2.2 ns rise time to a series combination of a capacitor C and resistance R = 50 Ω . There appears across R a pulse amplitude 1 V. Find the value of the capacitor C. 12 b) With block diagram explain the working of a offline UPS.

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Module – II 13. a) What do you mean by collector catching diode used in bistable multivibrator and explain its role.

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b) Determine the value of IC and VCE in self bias circuit, if R 1 = 10 kΩ , R 2 = 5.6 kΩ , R E = 560 Ω , R C = 1kΩ , VCC = 10 V and β = 100 .

OR

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14. a) Explain briefly the general guidelines for analysis of a transistor circuit.

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b) If an amplifier has a bandwidth of 200 KHz and voltage gain of 80, what will be the new bandwidth and gain if 5% negative feed back is introduced ? 10 Module – III 15. a) Draw the circuit of a TTL NAND gate. Explain the shape of transfer characteristics. b) What is twin-tub process ? Explain with necessary diagram.

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OR 16. a) Draw the CMOS inverter IC layout and explain its operation.

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b) Write down the equation for propagation delay of a CMOS inverter. Explain the factors affecting the propagation delay. 10

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Branch 03-304 ELECTRONIC CIRCUITS (RF)