R7100407-electronic Devices And Circuits

1

Code No: R7100407

I B.Tech (R07) Regular & Supplementary Examinations, June 2009 ELECTRONIC DEVICES AND CIRCUITS (Common to Electronics & Communication Engineering, Computer Science & Engineering, Electronics & Instrumentation Engineering, Information Technology, Electronics & Control Engineering, Computer Science & Systems Engineering and Electronics & Computer Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. Derive the expression for the deflection in an electrostatic deflection system. Hence obtain the expression for electro static deflection sensitivity. [16] 2. (a) Explain the volt ampere characteristics of PN diode. (b) Explain the temperature dependence of VI characteristics.

[8+8]

3. Draw the circuit diagram of a FWR: (a) With centre tap connection and (b) Bridge connection and explain its operation. 4. Explain the construction & Working function of NPN transistor in detail.

[16] [16]

5. (a) Explain stability factor in detail. (b) Explain the factor affecting stability of Q point.

[8+8]

6. Derive the expressions for voltage gain, current gain, I/P impedance, O/P impedance of CC amplifier, using exact & approximate model. [16] 7. (a) compare various negative feedback topologies. (b) Give the significance of positive & Negative feedback.

[8+8]

8. Draw a neat circuit diagram of RC phase shift oscillator using BJT and explain its working principle. [16] ?????

2

Code No: R7100407

I B.Tech (R07) Regular & Supplementary Examinations, June 2009 ELECTRONIC DEVICES AND CIRCUITS (Common to Electronics & Communication Engineering, Computer Science & Engineering, Electronics & Instrumentation Engineering, Information Technology, Electronics & Control Engineering, Computer Science & Systems Engineering and Electronics & Computer Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. What are the front panel controls of CRO? Explalin.

[16]

2. (a) Define Mass Action Law. (b) Explain N type & P type Semiconductors.

[4+12]

3. (a) Why do we need filters in a power supply under what condition we shall prater a capacitor filter? (b) Draw the block diagram of RPS. (c) What is the function of a bleeder resistor? (d) Describe the terms capacitor input filter and inductor input filter.

[5+2+5+4]

4. (a) Define a Transistor. (b) What are the differences between Bipolar Junction transistor & Field effect Transistor? (c) Write any two applications of transistor.

[5+7+4]

5. (a) Explain the criteria for fixing operating point. (b) List out the different types of biasing methods.

[12+4]

6. Explain the following determination method of transistor h -parameters. (a) Graphical Determination (b) Experimental Determination.

[16]

7. Briefly explain the current shunt feedback, also find the gain, input impedance and output impedance. [16] 8. Explain briefly about frequency and amplitude stability of oscillators. ?????

[16]

3

Code No: R7100407

I B.Tech (R07) Regular & Supplementary Examinations, June 2009 ELECTRONIC DEVICES AND CIRCUITS (Common to Electronics & Communication Engineering, Computer Science & Engineering, Electronics & Instrumentation Engineering, Information Technology, Electronics & Control Engineering, Computer Science & Systems Engineering and Electronics & Computer Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. Derive the expression for the deflection in a magnetic deflection system. Hence obtain the expression for magnetic deflection sensitivity. [16] 2. (a) Compare Tunnel diode & Conventional PN Diode. (b) Write any four applications of Tunnel diode.

[10+6]

3. Draw the circuit diagram of a FWR: (a) With centre tap connection and (b) Bridge connection and explain its operation.

[16]

4. (a) Why we call FET as a voltage controlled device? (b) Write about the broad classification of FET. (c) Draw the circuit symbol of P Channel N Channel FET.

[4+6+6]

5. (a) Give the significance of voltage divider bias and also explain the voltage divider bias. (b) Find the stability factor of voltage divider bias.

[10+6]

6. (a) Compare AV , Ai , Ri &R0 of CE, CB and CC configuration. (b) The h-parameters of a transistor used in a CE circuit are hie = 1.0 K Ω, hre = 10×10−4 , hf e = 50, hoe = 100 K. The load resistance for the transistor is 1 K Ω in the collector circuit. Determine Ri , Ro , AV , Ai in the amplifier stage (Assume Rs = 1000 Ω). [4+12] 7. (a) With neat sketch, explain the voltage series feedback. (b) Find the input-impedance, output impedance and gain of voltage series feedback. [5+11] 8. Explain the working principle of transistor pierce crystal oscillator and parallel resonant crystal oscillator. [16] ?????

4

Code No: R7100407

I B.Tech (R07) Regular & Supplementary Examinations, June 2009 ELECTRONIC DEVICES AND CIRCUITS (Common to Electronics & Communication Engineering, Computer Science & Engineering, Electronics & Instrumentation Engineering, Information Technology, Electronics & Control Engineering, Computer Science & Systems Engineering and Electronics & Computer Engineering) Time: 3 hours Max Marks: 80 Answer any FIVE Questions All Questions carry equal marks ????? 1. Analyse the motion of an electron in a magnetic field and derive the equations for the radius, time period and angular velocity. [16] 2. (a) Explain the volt ampere characteristics of PN diode. (b) Explain the temperature dependence of VI characteristics.

[8+8]

3. Draw the circuit diagram of a FWR: (a) With centre tap connection and (b) Bridge connection and explain its operation.

[16]

4. (a) How the UJT differs from ordinary PN diode. (b) Explain the construction of UJT. (c) Draw and explain the equivalent circuit of UJT.

[4+6+6]

5. (a) Explain the criteria for fixing operating point. (b) List out the different types of biasing methods.

[12+4]

6. Explain the following determination method of transistor h -parameters. (a) Graphical Determination (b) Experimental Determination.

[16]

7. (a) How the distortion is decreased in negative feedback? (b) An amplifier has an open loop gain of 1000 and a feedback ration of 0.04. if the open loop gain changes by 10% due to temperature, find the percentage change in gain of he amplifier with feed back. [10+6] 8. Explain the operation of a transistorized Wein-bridge oscillator with the help of neat circuit diagram. How is amplitude stability achieved in this circuit? [16] ?????