FREQUENTLY ASKED QUESTIONS

Transcription

1 FREQUENTLY ASKED QUESTIONS UNIT-1 SUBJECT : ELECTRONIC DEVICES AND CIRCUITS SUBJECT CODE : EC6202 BRANCH: EEE PART -A 1. What is meant by diffusion current in a semi conductor? (APR/MAY 2010, 2011, NOV/DEC 2009) 2. Define diffusion capacitance and transition capacitance. (APRIL/MAY 2015) (NOV/DEC2014) 3. Write the temperature dependence of reverse saturation current of PN junction diode. 4. A silicon diode has a saturation current of 7.5 µ A at room temperature 300 K.Calculate the saturation current at 400 K. (APR/MAY 2010, 2011) 5. Define Knee voltage of a diode. (NOV/DEC 2010) 6. What is peak inverse voltage? (NOV/DEC 2010) 7. What are the applications of LED. (APR/MAY 2010) 8. What is PN junction diode. How is it formed. (APR/MAY 2012) 9. What is LED? Draw its symbol. (APR/MAY 2012, 2013) 10. What is LED? Which material is used for LED? (NOV/DEC 2009) 11. Define diffusion capacitance and transition capacitance. 12. Mention the advantage of bridge rectifier over full wave rectifier (APRIL/MAY 2015) 13. What is meant by depletion region? 14. What are the advantages of bridge rectifier over center tapped counterpart? 15. Define line regulation of voltage regulator. (NOV/DEC2016) 16. Define biasing? 17. What are the static resistance and dynamic resistance of a diode? (NOV/DEC 2011) 18. What is the effect of junction temperature on cut-in voltage of a PN diode? 19. Differentiate between breakdown voltage and PIV of a PN diode. 20. Differentiate avalanche and zener breakdowns. (NOV/DEC 2011) 21. List the PN diode parameters. 22. List some applications of zener diode. 23. State the principle of operation of an LED. 24. Define Zener diode. 25. Define rectifier. What are the different types of rectifiers? (NOV/DEC2016) 26. Explain briefly about laser diode.

2 27. Relate voltage and current of forward biased PN junction diode. (MAY/JUNE 2014) 28. Differentiate LED and LCD. (MAY/JUNE 2014) 29 What is rectifier and list its types (APRIL/MAY 2015)(NOV/DEC2014) 30. Draw the VI characteristics of Zener diode (APRIL/MAY 2015) 31.Differentiate between zener breakdown and avalanche breakdown. (APR/MAY 2017) 32.Mentiopn some of the application of laser diode. (APR/MAY 2017) PART -B 1. With a neat diagram explain the working of a PN junction diode in forward bias and reverse bias and show the effect of temperature on its V-I characteristics. (16) (NOV/DEC2016)(APRIL/MAY 2015,2013,2014,2010, 2011, NOV/DEC 2009, 2012) 2.Explain V-I characteristics of Zener diode. (APR/MAY 2010) 3.Draw the circuit diagram and explain the working of full wave bridge rectifier and derive the expression for average output current and rectification (APR/MAY 2010, 2011, 2017) efficiency. (8) (NOV/DEC2016) 4. (i)explain the operation of FWR with center tap transformer. (6) Also derive the following for this transformer. (ii) DC output voltage (4) (iii) DC output current (2) (iv) RMS output voltage, TUF and PIV (4) (NOV/DEC 2010, 2009, 2011) 5. (i)explain the operation of HWR with centre tap transformer. (6) Also derive the following for this transformer. (ii) dc output voltage (4) (iii) dc output current (2) (iv) RMS output voltage, TUF and PIV (4) (APRIL/MAY 2015)(APR/MAY 2012) 6. Define full wave rectifier. With neat circuit diagrams and waveforms, Derive an expression for a ripple factor in full wave rectifiers the load is resistive (APRIL/MAY 2015) (NOV/DEC 2009) 7. Explain the operation of Zener diode as voltage regulator.(6) (APRIL/MAY ) (MAY/JUNE 2014)(NOV/DEC 2010, 2009, APR/MAY 2013) 8. Explain the working of Bridge rectifier. Give the expressions for RMS current, PIV, ripple factor and efficiency. (MAY/JUNE 2014) (NOV/DEC2014) 9. Discuss the working principle, characteristics and applications of LED in detail. (NOV/DEC 2009, 2011) 10. Explain the drift and diffusion current for a semiconductor. (APR/MAY 2012, 2013) 11. Discuss the working principle, characteristics and applications of LED in detail. (APRIL/`MAY 2015) 12. Briefly discuss about the following : (i) Laser diode

3 (ii) switching characteristics of pn junction diode (APRIL/MAY 2015) 13. Draw the expression for diffusion capacitance of PN junction diode. (APR/MAY 2017) 14. Explain how zener diode can be acts as a voltage regulator. (APR/MAY 2017)

4 UNIT II PART -A 1. Draw the input and output characteristics of a transistor in CE configuration and mark the cutoff, saturation and active regions. ( APR/MAY 2010, APR/MAY 2010) 2. Compare JFET & BJT (APR/MAY 2015,2010, NOV/DEC 2014) 3. Define amplification factor of JFET (APR/MAY 2010) 4. Calculate β of a transistor when α=0.98 (NOV/DEC 2012) 5. Among CE,CB &CC configurations, which one is the most popular? Why? (NOV/DEC 2012) 6. Define pinch off voltage of a FET. (NOV/DEC 2012) 7. Name the operating modes of a transistor. (NOV/DEC 2010) 8. What is meant by punch through effect? 9. Define Base Width modulation. 10. Why collector region is larger than emitter region in BJT? (NOV/DEC 2009) 11. In a BJT, the emitter current is 12mA and the emitter current is 1.02times the collector current. Find the base current. (NOV/DEC 2009) 12. Determine the emitter current for the transistor circuit if Ic = 80mA and beta = Define pinchoff voltage. (APR/MAY 2009) (NOV/DEC 2009) 14. Calculate the drain current for self-bias an N channel JFET with I Dss = 40mA, Vp= -10v and V GS = -5V. (NOV/DEC 2009) 15. Write the relationship between base current, emitter current and collector current in CB Configuration. (APR/MAY 2010, 2012) 16. Mention the disadvantages of FET compared to BJT. (NOV/DEC 2012) 17. Define pinch off voltage of JFET. (APR/MAY 2013) 18. How transistor can be used as a switch? (NOV/DEC 2016) 19. What are the biasing conditions to operate transistor in active region? 20. Why is the transistor called a current controlled device? 21. When a transistor is used as a switch, in which region of output characteristics it is operated?

5 22. Why collector region wider than emitter region in BJT? (NOV/DEC 2009) 23. If the base current in a transistor is 30μA and the emitter current is 7.2mA. What are the values of α, β and Ic? 24. Explain the output characteristics of transistor. 25. What is operating Point? (NOV/DEC 2016) 26. What is the relation between α and β of a transistor? 27. Why must the base be narrow for the transistor (BJT) action? 28. What are the important features of FET? (NOV/DEC 2009) 29. Comparison between JFET and MOSFET 30. What are the advantages of FET over BJT? 31. What is MOSFET? What are the types of MOSFET? (APR/MAY 2010, 2012) 32. Mention application of UJT.(APR/MAY 2012) 33. Give any 2 difference between E-MOSFET & D-MOSFET. (NOV/DEC 2011) 34. What is biasing? (NOV/DEC 2014) 35. Compare IGBT & MOSFET. 36. Why the base region is there in BJT? (APR/MAY 2015) 37. What are power transistors (APR/MAY 2015) 38 what are thyristors? Mention two of them. (APR/MAY 2015) 39. Draw the two transistor equivalent circuit of SCR. (APR/MAY 2017) PART-B 1. Describe the static input and output characteristics of a CB transistor with neat circuit diagram. (16) (NOV/DEC 2010) 2. Describe the static input and output characteristics of a CB transistor with neat circuit diagram and also explain the early effect. (16) (APR/MAY 2015, NOV/DEC 2009, 2010,2011,2016) 3.Describe the static input & output characteristics of a CE transistor with neat circuit diagram. (APR/MAY 2010, 2012, 2013, 2015, NOV/DEC 2009)

6 4. Explain the construction and operation of N channel JFET with neat sketches and characteristics curve. Also explain the three distinct regions of the output characteristics. (APR/MAY 2012) (NOV/DEC2016) 5. Derive the expression for current gain, input impedance and voltage gain of a CE Transistor Amplifier. (16) (NOV/DEC 2010) 6. Distinguish between the different types of transistor configurations with necessary circuit diagrams. 7. Explain how the trans conductance of a JFET varies with drain current and gate voltage characteristics and transfer characteristics (APR/MAY 2010) 8. Explain the working of n channel enhancement type MOSFET. Sketch its typical characteristics. (APR/MAY 2015, 2010, NOV/DEC 2009, 2011) 9. With the help of suitable diagrams explain the working of different types of MOSFET. (APR/MAY 2010) 10. Describe the operation of UJT and its emitter characteristics.(apr/may 2010,NOV/DEC 2011) 11. Explain in detail the construction and working principle of depletion MOSFET. Also explain how depletion MOSFET acts both in enhancement and depletion mode. (NOV/DEC 2009) 12. Present and explain the structure of current flow mechanism of MOSFET in detail. (NOV/DEC 2012) 13. Explain various biasing methods used in FET & BJT. 14. Describe the construction operation and V-I characteristic of SCR with neat diagram. (NOV/DEC 2014) 15. Describe construction details about IGBT. Compare IGBT & BJT. (APR/MAY 2017) 16. (i) explain the input / output characteristics of BJT in common base configuration.(11) (MAY JUNE 2014) (ii) Compare CE, CB and CC configuration of BJT(5) MAY JUNE 2014) 17. (i) Draw the hybrid π model of BJT and obtain expression for various parameters(12) (MAY JUNE 2014)

7 (ii) Compare BJT and power transistor (4) (MAY JUNE 2014) 18. Explain the construction operation and characteristics of NPN transistors (NOV/DEC 2014) 19. Compare the performance of a transistor in different configuration. (APR/MAY 2012.) 20. Construction and working of opto couplers (6) (APRIL/MAY 2015) 21. Brief about the transistor switching characteristics (APRIL/MAY 2015) 22. Describe the construction & working of UJT with its equivalent circuit & VI characteristics (APRIL/MAY 2015) 23. Draw hybrid and derive for its parameters. (NOV/DEC2016) 24. Draw CE hybrid model and CB hybrid model. (NOV/DEC2016) 25. Sketch and explain the typical shape of drain characteristics of JFET for Vgs is 0. With indication of four region clearly. (APR/MAY 2017) 26. Explain the drain and transfer characteristics of Enhancement type MOSFET. (APR/MAY 2017) 27. Describe the working of SCR with neat diagram. (APR/MAY 2017)

8 UNIT III PART A 1. What is the function of bypass capacitor in an amplifier circuit? 2. Define the four H-parameters. (NOV /DEC2014) 3. Define small signal amplifier. (APR/ MAY 2011) 4. Write down the characteristics of CE amplifier. (APR/ MAY 2011) 5. Write down the characteristics of CC amplifier. 6. Why voltage divider bias is commonly used in amplifier circuit? 7. What is an amplifier? (APR/ MAY 2010, 2015) 8. Based on the transistor configuration how amplifiers are classified. (NOV/DEC 2013) 9. Write the Hybrid parameters equation for transistor amplifier? (NOV/DEC 2013) 10. Write the CE amplifier Current gain, Voltage gain, Input Impedance, Output Impedance in terms of h-parameters. (APR/ MAY 2011) 11.Draw a CE amplifier & its hybrid equivalent circuit. (APR/ MAY 2014) 12.Which amplifier is called as voltage follower? Why? (NOV/DEC 2013) 13.Why hybrid parameters are called so? Define them? (APR/ MAY 2014) 14.What are the salient features of hybrid parameters? 15.What are the limitations of `h parameters? (APR/ MAY 2013) 16. Define the frequency response of Amplifier? 17. Define lower & upper cut off frequencies of an amplifier. 18. What are the different types of MOSFETs? (NOV/DEC 2016) 19. State the reason for fall in gain at low frequencies. 20. State the reason for fall in gain at higher frequencies? 21. Write a note on effects of coupling capacitor.(apr/ MAY 2013) 22. Draw the drain characteristics of FET and mark operating region 23. Compare BJT and FET (APR/ MAY 2010)

9 24. For an amplifier, mid band gain= 100 and lower cut off frequency is 1kHz. Find the gain of an amplifier A r frequency of 20 Hz (NOV /DEC 2014) 25. why FET is known as voltage controlled devices? (APR/MAY 2015) 26. Draw the circuit diagram of a CS FET amplifier (APR/MAY 2015) 27. Define cut off voltage. (NOV/DEC 2016) 28. Define an intrinsic stand off ratio of UJT and draw it equivalent circuit. (APR/MAY 2017) 29 A CE amplifier has an input resistance of 2.5 k and voltage gain of 200. If the input Signal voltage of 5 mv. Find the base current of the amplifier. (APR/MAY 2017) PART-B 1. (i)derive the expressions for the following of a small signal transistor amplifier in terms of the h-parameters (a)current gain (b) voltage gain (c) input impedance (d) output admittance. (12) (ii) Compare CB, CE and CC amplifiers. (4) 2. Explain how the transconductance of a JFET varies with drain current and gate voltage characteristics and transfer characteristics. A JFET has the following parameters IDDS = - 32mA,VGS(off) = - 8V, VGS = - 4.5V. Find the values of drain current. (APR/ MAY 2010, 2011) 3. Explain the working of n channel MOSFET, thus obtain the VI characteristics and what is the significance of pinch off voltage. (APR/MAY 2015, 2010,2011,NOV/ DEC 2010) 4. Using the h-parameters model, derive the expressions for current gain AI, input impedance, and Voltage gain AV and output impedance of CE Transistor Amplifier? 5. Define the h-parameters of a Transistor in a small signal Amplifier? What are the benefits of h-parameters? (APR/ MAY 2013,NOV/DEC 2011) 6. In a single-stage CE Transistor Amplifier, R S = 1 kω and R L = 1.2 kω, using h fe = 50, h oe = A/V, h re = , h ie = 1100 Ω, find A I, A V, Z i and Z o. 7. With the help of necessary equations, discuss variations Ai, Ri, Ro and A V with R S and R L in CE Transistor Amplifier? (NOV/DEC 2011) 8. What are the h-parameters? Why are they called so? Define them and what are the benefits of h-parameters? (APRIL/ MAY 2011) 9. In a single-stage CE Transistor Amplifier with an un-bypassed Emitter resistance, R o = 1 kω, R 1 = 50 kω, R 2 = 2 kω, R E = 270 Ω and R L = 1.2 kω. Find A I, A V, R i and R o. The h- parameters given are h ie = 1100 Ω and h fe = 50

10 10. Draw the low-frequency h-parameter equivalent circuit of Transistor Amplifier and explain the significance of each parameter 11. In a single-stage CE Transistor Amplifier R S = 1 kω, R 1 = 50 kω, R 2 = 2 kω, R C = 1 kω, R L = 1.2 kω, h fe = 50 and h ie = 1.1 kω. Find A I, R i, R o and voltage gain. 12. Give typical values of h-parameters for CC Transistor configuration. 13. Draw the circuit of CE Transistor Amplifier and its equivalent circuit. Discuss its characteristics. (MAY/JUNE 2013) 14. Draw the circuit diagram of Emitter follower and its equivalent circuit and derive the expression for voltage gain. 15. Draw the circuit of CB Transistor Amplifier and its h-parameter equivalent circuit. Discuss the characteristics of CB Amplifier. (NOV/DEC 2013) 16. Compare the CC and CE configurations with respect to R i, R o, A V and A I. 17. Draw a typical CE Amplifier and explain the function of each component. 18. (i)describe the operation of common drain FET amplifier and derive the equation for voltage gain. (12) (NOV/DEC 2013) (ii) In the common drain FET amplifier. Evaluate the voltage gain (4) (NOV/DEC 2013) 19. For a common emitter circuit draw the h-parameter equivalent circuit & write the expressions for input impedance, output impedance and voltage gain. (APR/ MAY 2011, 2015) 20. Draw the circuit diagram of common source FET amplifier and give the design steps to find the component values used in the circuit. (16) (APRIL/MAY 2011, NOV/ DEC 2011) 21. (a)draw the low frequency hybrid equivalent circuit for CE & CB amplifier. (b) Give the approximate h-parameter conversion formulae for CB and CC con-figuration in terms of CE. (c) (d) Give the advantages of h-parameter analysis. Give the procedure to form the approximate h-model from exact h-model of amplifier (NOV/DEC 2012) 22. Explain the construction, working and static drain characteristics of enhancement type MOSFET (APR/MAY 2015,MAY/ JUNE 2014) (NOV/DEC 2016) 23. Derive the expression for the voltage gain of i) Common source amplifier 24. Prove that Darlington amplifier offers very high input impedance Y/ JUNE 2014) 25. Draw the h parameter equivalent circuit for a typical common emmiter amplifier and

11 derive expression for Ai, Ri, Av and Ro.(NOV / DEC 2014) 26. (i) dderive the expression for the voltage gain of CS amplifier(8) V / DEC 2014) (ii) For CS amplifier, the operating point is defined by V gsq =-2.5V, V p =-6V and I dq =2.5mA with I dss =8mA. Also R g =1MΩ,R s =1KΩ,R d =2.2KΩ and V dd = 15V, calculate g m,r d,z i,z o and A v. (NOV / DEC 2014) 27. Compare the construction, operation and characteristics of enhancement and deletion MOSFET. (APR/MAY 2015) 28. What is the significance of Darlington pair connections(6) R/MAY 2015) ii) Common drain amplifier configurations, under small signal low frequency condition 29. (i) Cascade amplifier have high bandwidth. Validate this statement suitably.(may/june 2014) (ii) For CS amplifier draw the small signal equivalent circuit and determine the express for gain, input impedance and output impedance. (MAY JUNE 2014) 30. Explain the construction and working principle of a FET. Draw the relevant characteristics. (NOV/DEC 2016) 31. Draw the circuit diagram of a Common drain MOSFET amplifier. Derive the expression for tis voltage gain, input resistance and output resistance. (APR/MAY 2017)

12 UNIT IV PART -A 1. Name the types of feedback amplifiers. (MAY/JUNE-2013) 2. State piezo-electric effect. (MAY/JUNE-2013) 3. State Bharkausen s criterion for oscillation. (NOV/DEC2013, 2014) 4. Mention the types of feed back amplifier connections. (NOV/DEC2013) 5. Define CMRR of a differential amplifier (MAY/JUN 2014) (APR/MAY 2017) 6. State the conditions to obtain sustained in oscillator circuit? (MAY/JUN 2014, 2015) 7. List the factors that affects the stability of amplifiers (NOV/ DEC 2014) 8. Write down the need of cascading the amplifiers. (NOV/ DEC 2014) 9. What is CMMR list the various methods of improving CMRR. (NOV/ DEC 2014) 10. Define CMRR and write its significance in the differential amplifiers. (APR/MAY 2010) 11. List the Advantages of negative feedback amplifiers (APR/MAY 2010) 12. What is an oscillator? 13. What are sustained oscillations? (APR/ MAY 2011) 14. What are the different feedback topologies? 15. What are the effects of negative feedback? (APR/ MAY 2012) 16. Which oscillator uses both positive and negative feedback? 17. What are the different types of feedback depending in the type of feedback signal? 18. Distinguish between series and shunt feedback. (APR/ MAY 2012) 19. Define sensitivity factor. 20. Why negative feedback is employed in high gain amplifiers? 21. Comment on the stability of feedback amplifier. (APR/MAY 2015)

13 22. What are the cascaded amplifiers? (APR/MAY 2015) 23. How are amplifiers classified according to negative feedback. (NOV/DEC 2016) 24. Draw the equivalent circuit of crystal oscillator. (NOV/DEC 2016) 25. Compare the performances of CE and CC configuration. (APR/MAY 2017) PART B 1. Draw the circuit diagram of an emitter coupled BJT differential amplifier and derive expressions for differential gain, common mode gain, CMRR, input impedance and output impedance. (MAY/JUNE 2013) 2. Explain the general characteristics of negative feedback amplifier in Voltage series, Voltage shunt, Current series, Current shunt feedback connections diagrammatically.(16) ( NOV/DEC 2013) 3. Derive expressions for differential gain, common mode gain, CMRR, input impedance and output impedance for a differential amplifier. (MAY/JUNE 2013). 4. A Harley oscillator is designed with L1 = 2mH, L2 = 20µH and a variable capacitance. Determine the range of capacitance value if the frequency of oscillation is varied between 950 to 2050 KHZ.(16) (APR/ MAY 2011) 5. Draw the circuit diagram of a current series feedback amplifier and derive expressions for voltage gain with and without feedback. 6. (i)explain in detail about the different feedback topologies.(8) (APR/MAY 2015,NOV/DEC 2012) (ii)draw the circuit diagram of a voltage series feedback amplifier and derive expressions for voltage gain with and without feedback. (8) 7. Briefly explain about differential amplifiers. 8. (i) Write notes on frequency stability of an oscillator. (ii) A negative feedback of β = 0.01 is applied to an amplifier of gain 500. Calculate the change in overall gain of the feedback amplifier if the internal amplifier is subjected to a gain reduction of 10 %.

14 9. Explain with a neat sketch the working of single tuned voltage amplifier using FET. Derive the frequency response of single tuned voltage amplifier and also give its limitations. (NOV/DEC 2012) 10. Explain the different types of neutralization techniques used in tuning amplifier.(apr/ MAY 2012) 11. Explain the effects of negative feedback in amplifiers. (APR/MAY 2015) 12. What is neutralization? Explain any one method in brief. (APR/MAY 2015) 13. Draw circuit of emitter coupled BJT differential amplifier and derive expression for the differential mode gain, common mode gain and CMRR. (APR/MAY 2015) 14. Describe the principle of (i) Positive feedback, (ii) Negative feedback. Also derive the barhausion criterion. (NOV/DEC 2016) 15. Describe the working of Class A and Class C power amplifier in details with relevant diagrams. (APR/MAY 2017) 16. Draw the circuit diagram and explain the working of a differential amplifier using FET. Derive the expression for differential mode gain and common mode gain. (APR/MAY 2017)

15 UNIT V FEEDBACK AMPLIFIERS AND OSCILLATORS PART A 1. How is a Schmitt trigger different from multi vibrator (MAY/JUNE 2013) 2. Define intrinsic standoff ratio (NOV/DEC2013) 3. What is meant by hysteresis in schmitt trigger? (MAY/JUN 2014) 4. Give the two barkhausen conditions required for sinusoidal oscillation to be sustained. (APR/MAY 2017) 5. A tuned circuit has a resonant frequency of 1600 khz and bandwidth of 10kHz. What is the value of its Q factor. (APR/MAY 2017) 6. Mention few applications of multi vibrators. (MAY/JUN 2014) 5. List the applications of astable multivibrators (NOV/ DEC 2014) 6. Which is the most commonly used feedback arrangement in cascaded amplifier and why? (NOV/ DEC 2014) 7. State the Barkhausen criterion for an oscillator. (NOV/ DEC 2014, 2013) 8. Define intrinsic standoff ratio of UJT and draw its equivalent circuit. (APR/MAY 2010) 9. Mention the effects on bandwidth and output impedance due to various types of feedback. 10. Negative feedback is preferred to other methods of modifying amplifier characteristics. Why? 11. What is the effect of voltage series feedback on input resistance? 12. What are the advantages of negative feedback? 13. What is an oscillator? 14. What is the difference between an oscillator and amplifier? 15. What is damped oscillation? 16. What is sustained oscillation? 17. What are the essential parts of an oscillator? 18. Give the condition of oscillation for Hartley oscillator

16 19. Name two high frequency oscillators. (NOV/DEC 2010) 20. Why crystal oscillators are superior to other oscillators? 21. What is meant by un-sustained oscillation? When it will occur? 22. How oscillations occur in a crystal oscillator? 23. What are the advantages of crystal oscillator? (NOV/DEC 2012) 24. What type of feedback used in an Op-amp Schmitt trigger? (NOV/DEC 2016) 25. What is free running multi vibrator? (NOV/DEC 2016) 25. Define: Piezo electric effect (MAY/JUNE 2013) 26. Mention the types of feedback amplifiers. (NOV/DEC 2013) List the elements used in linear and nonlinear wave shaping circuits.(apr/may 2015) Name the different multivibrators. (APR/MAY 2015) 29 What is the expression for the frequency of oscillation of a wein bridge oscillator? (APR/MAY 2015) 30 Write the drawbacks of negative feedback in amplifiers and how it can be overcome. (APR/MAY 2015)

17 PART B 1) Draw and describe the four types of topology for feedback of an amplifier. Derive the expression for gain with feedback. Mention the advantages of negative feedback amplifier.(16) (NOV/DEC 2013) 2) Explain the working of UJT based saw tooth oscillators. Also derive the expression for frequency of oscillation.(16) (APR/MAY 2015,MAY/JUNE 2013,NOV/DEC 2014) 3) Draw saw tooth oscillator and explain its operation with its circuit diagram and output waveforms (16) ( MAY/JUNE 2014) 4) With a neat diagram explain about Hartley oscillator & derive the expression for frequency of oscillation and condition of oscillation. (16) (NOV/DEC 2013, 2014) 5) With neat circuit diagram explain the operation of an RC phase shift oscillator and derive the condition for oscillation and resonant frequency with BJT. (NOV/DEC 2012) 6) Explain the operation of crystal oscillator with neat diagram and write the expression for its frequency of oscillation.(16) (MAY/JUNE 2012) 7) Draw the circuit diagram of Schmitt trigger circuit and explain its operation with waveforms. (NOV/ DEC 2013) 8) With a neat circuit diagram, describe the working of a Wien bridge oscillator. Derive an expression for the resonant frequency. How output amplitude is stabilized? (16) 9) Voltage series negative feedback amplifier has a voltage gain without feedback of A = 500, input resistances (Ri) = 3KΏ, output resistance Ro = 20KΏ, and feedback ratio of β = Calculate the voltage gain A V, input resistance (R if ) and output resistance (R of ) of amplifier with feedback. (16)

18 10) A Hartley oscillator is designed with L1 = 2mH, L2 = 20µH and a variable capacitance. Determine the range of capacitance value if the frequency of oscillation is varied between 950 to 2050 KHZ.(16) 11) Discuss the operation of Astable and one shot multi vibrator with relevant waveforms. (APR/MAY 2015) 12) Draw the circuit of CE amplifier with current series feedback and obtain the expression for feedback ratio, voltage gain and input and output resistance (APR/MAY 2015) 13) Explain the operation of colpitts oscillator with neat circuit diagram also derive for the frequency of oscillation & the condition for maintaining oscillation (APR/MAY 2015) 14) Explain the operation and characteristics of UJT relaxation oscillator. (NOV/DEC 2016) 15) With neat diagram, describe the operation and characteristics of monostable multi vibrator and its applications. Derive for its ON time. (NOV/DEC 2016) 16) Design an oscillator to operate at a frequency of 10 khz which gives an extremely pure sine wave output, good frequency stability and highly stabilized amplitude. Discuss the operation of the oscillator as an audio signal generators. (APR/MAY 2017) 17) Design a voltage divider bias circuit for transistor to establish the quiescent point at Vce=12V, Ic=1.5 ma, Stability factor S<=3, = 50, Vbe = 0.7 V, Vcc=22.5V and Rc=5.6 k. (APR/MAY 2017) 18) Explain the operation of Hartley oscillator. Derive for the frequency of oscillation. How conditions of oscillation are met? (APR/MAY 2017) (NOV/DEC 2016) 19) With a neat block diagram, explain the operation of following feedback amplifiers. (i) Voltage series feedback amplifier, (ii) Current shunt feedback amplifier. (APR/MAY 2017)