Analog Electronic Circuits unit 7 vtu

7/22/2019 Analog Electronic Circuits unit 7 vtu

1/48

ANALOG ELECTRONIC CIRCUITS

(VTU)

3rdSem EC/EE/TC

UNIT 7:

Oscillators:Oscillator operation, Phase shift Oscillator, Wienbridge Oscillator, Tuned Oscillator

circuits, Crystal Oscillator. (Chapter 14.5 to 14.11) (BJT version only)

6 Hours

TEXT BOOK:

1. Electronic Devices and Circuit Theory, Robert L. Boylestad and Louis Nashelsky,

PHI/Pearson Education. 9TH Edition.

REFERENCE BOOKS:

1. Integrated Electronics, Jacob Millman & Christos C. Halkias, Tata - McGraw Hill, 2nd

Edition, 2010

2. Electronic Devices and Circuits,David A. Bell, PHI, 4thEdition 2004

3. Analog Electronics Circuits: A Simplified Approach, U.B. Mahadevaswamy,

Pearson/Saguine, 2007.

BY:

RAGHUDATHESH G P

Asst Prof

ECE Dept, GMIT

Davangere 577004

Cell: +917411459249

OSCILLATOR RAGHUDATHESH G P Asst.Prof

Page.No-1


2/48



3/48



4/48



5/48



6/48



7/48



8/48



9/48



10/48



11/48



12/48



13/48



14/48



15/48



16/48



17/48



18/48



19/48



20/48



21/48



22/48



23/48



24/48



25/48



26/48



27/48



28/48



29/48



30/48



31/48



32/48



33/48



34/48



35/48



36/48



37/48



38/48



39/48



40/48



41/48



42/48



43/48



44/48



45/48



46/48



47/48

Question Bank

1. Explain briefly, what do you mean by an electronic oscillator? Give two applications of an

oscillator.

2. Explain the meaning of the terms:

i. damped oscillations ii. Undamped oscillations.

3. What are the factors which affect the frequency stability of an oscillator.

4. State and explain the Barkhausens criteria to obtain sustained oscillations.

5. What is Barkhausen criterion? Explain how oscillations start in an oscillator.

6. How oscillators are classified and give an example for each.

7. Define loop gain.

8. What type of feedback is applied for oscillator and explain the same.9. Define Q of tank circuit.

10.With the help of a circuit diagram explain the working of an RC phase shift oscillator andWrite the expression for the frequency of sustained oscillation.

11. Derive the expression for sustained frequency of oscillation for RC phase shift oscillator.12. Why do we need three RC networks for a phase shift oscillator? Can it be two or four.13. With the help of a circuit diagram explain the working of an Wien Bridge oscillator and

Write the expression for the frequency of sustained oscillation.

14. Derive the expression for sustained frequency of oscillation for Wien Bridge oscillator.15. Write the advantages and disadvantages of RC phase shift oscillator and Wien Bridge

oscillator.

16. Write the differences between RC phase shift oscillator and Wien Bridge oscillator.17. Calculate the frequency of a Wien Bridge oscillator circuit when R = 12 k ohm and C =

2400 pf.

18. Design a Wein Bridge oscillator for a frequency of 5 KHz.19.With the help of a circuit diagram explain the working of an Hartley oscillator and Write

the expression for the frequency of sustained oscillation.

20.Derive the expression for sustained frequency of oscillation for Hartley oscillator.21.With the help of a circuit diagram explain the working of an Colpitts oscillator and Write

the expression for the frequency of sustained oscillation.


Page.No-47


48/48

22. Derive the expression for sustained frequency of oscillation for Colpitts oscillator.

23. A colpitts oscillator has C1= C2= C and L = 100H, frequency of oscillation is 500 KHz.

Determine the value of CeQ

24. What is piezoelectric effect? Draw the equivalent circuit of quartz. Describe the crystal

oscillator with neat circuit diagram

25. Draw the electrical equivalent circuit of quartz crystal oscillator and write the expression

for series and parallel resonant frequencies.

26. Crystal oscillator possess high degree of frequency stability-justify.

27. A crystal oscillator has L = 0.4H, C = 0.085PF and CM= 1PF with R = 5K, find

i) Series resonant frequency ii) Parallel resonant frequency iii) Quality factor of crystal


Analog Electronic Circuits unit 7 vtu

Documents

Transcript of Analog Electronic Circuits unit 7 vtu