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Reg. No. : .................................... Name : .........................................
Third Semester B.Tech. Degree Examination, November 2009 (2008 Scheme) Branch : Electrical and Electronics 08.305 : SOLID STATE DEVICES & CIRCUITS (E) Time : 3 Hours
Max. Marks : 100 PART – A
Answer all questions from Part A.
(4×10=40 Marks)
1. What is the role of emitter by pass capacitor in a biasing circuit of BJT ? 2. How gain of a JFET can be obtained from its characteristics ? 3. What is thermal run away ? 4. Define bandwidth of an amplifier. 5. Why it is preferred to express the gain of an amplifier in deci Bel ? 6. What is cross over distortion in amplifier ? How it can be eliminated ? 7. State Barkhausen criteria for sustained oscillations. 8. Explain input offset voltage and thermal drift of an Op-Amp. 9. Define CMMR and slew rate of a Op-Amp. 10. Why the Q-point of a BJT amplifier should be stable ? PART – B Answer any one full question from each Module. Module – I 11. a) How h parameter can be obtained from the characteristics of a BJT ? Explain.
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b) Explain two bias compensation methods.
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c) Determine IB, IC and VCE for a base biased transistor circut with BDC = 90, VCC = 12 V, RB = 22 k Ω and RC = 100 Ω .
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8224 12. a) Explain the construction and working of a JFET.
b) Using small signal low frequency analysis obtain the expressions for input impedance, output impedance, voltage gain and current gain of a CE amplifier. c) For a JFET IDSS = 15 mA, VP = –10 V calculate the chain current for VGS = – 5 V.
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Module – II 13. a) Explain the frequency response curve of a RC coupled CE amplifier.
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b) Determine the maximum theoretical efficiency of a Class A power amplifier.
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c) Draw the circuit diagram for a Colpitts oscillator.
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14. a) Explain the working of a complementary symmetry push-pull amplifier.
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b) What are the advantages of negative feedback on amplifier ? Show how gain and input output impedances affected due to negative feedback.
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c) Draw the circuit of a Wein Bridge Oscillator.
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Module – III 15. a) Explain the working of an emitter coupled differential amplifier. Also find expression for CMMR. b) Show how Op-Amp can be used for the following purposes : i) Summing amplifier ii) Level detector iii) Differentiator. 16. a) Draw the circuit of an inverting amplifier using Op-Amp. Explain its operation and derive the expressions for gain.
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b) An Op-Amp is configured as non inverting summer, the supply voltage is ±15 V and input voltages are V1 = + 2 V, V2 = – 8 V, V3 = + 5 V. Input side resistance is 1kΩ and feedback resistance 2 kΩ . Find output voltage.
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c) Explain the following terms for an Op-Amp. i) Drift compensation ii) Frequency compensation.
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