Electronics Circuits Lab Viva questions

ELECTRONIC CIRCUITS LAB VIVA QUESTIONS

 CLIPPERS:

  1. What are the applications of clippers?
  2. Diode cut in voltage value for si and Ge diodes?
  3. Why the output of the clipper is taken in d.c mode?
  4. Other names of clippers are—— –.
  5. Voice frequency range is——– –.
  6. Positive peak clipper means
  7. Negative peak clipper means
  8. Positive base and negative base clippers means
  9. What is the difference between clipping and clamping operations?
  10. And the working procedures of each clipping circuit
  11. How clippers are applicable in noise reduction in audio applications?
  12. Draw the output waveforms of different clippers with different input and reference voltages—–
  13. Why clippers are called as diode clippers?
  14. What is the difference between slicing and clipping of a voltage waveform?
  15. Clippers comes under linear or non linear wave shaping?
  16. Explain linear and nonlinear wave shaping meanings?
  17. Names some linear and non linear wave shaping circuits?
  18. Define diode threshold and cutin voltages?
  19. An ideal diode acts as———– under forward
  20. An ideal diode acts as———— under reverse
  21. Practical diode equivalent circuit in forward bias——–
  22. Practical diode equivalent circuit in reverse bias——–
  23. Draw diode d.c characteristics.

CLAMPERS:

  1.  Define clamping operation? And how it is different from clippers?
  2. What are the other names of clampers?
  3. Difference between clipping and clamping circuits
  4. Why capacitors are used in clampers?
  5. What are different types of clampers?
  6. Working Operation of each clamper circuit
  7. Practical applications of clampers are
  8. What happens in the output waveform if the polarity of capacitor is changed in the clampers
  9. Capacitor acts as———- for D.C input
  10. Capacitor acts as————- for A.C
  11. Fully charged capacitor acts as——– –.
  12. What do u mean by transient and steady state response of a clamper?
  13. DC restorers are used in CRO’s yes or no
  14. DC inserter means————
  15. Voltage or amplitude slicers means———–
  16. Voltage or amplitude limiters means———– –.
  17. Explain the operation of positive peak clamper?
  18. What is the working principle of a capacitor/
  19. Output waveforms of clampers with different input and different reference voltages—
  20. The voltage across a capacitor remains———— once the capacitor is fully

SINGLE STAGE CE AMPLIFIER:

  1. What is the phase difference between input and output wave forms of a CE amplifier?
  2. What type of biasing is used in the given circuit?
  3. What is the effect of emitter bypass capacitor on frequency response of a CE amplifier?
  4. What is the effect or importance of coupling capacitor?
  5. Why source resistance Rs is used in the input side?
  6. What are the different regions of operation of a BJT?
  7. The phase difference of input and output in CB amplifier?
  8. CE amplifier is voltage or current amplifier?
  9. Draw the equivalent h-parameter model of a CE amplifier?
  10. Why NPN transistor is preferred over PNP transistor?
  11. What is the effect of bypass capacitor over stability of the CE amplifier?
  12. The CE amplifier is in voltage divider bias or in fixed bias configuration?
  13. The values of hfe,hie,hoe and hre in CE configuration are———– –.
  14. hfe,hie,hoe and hre are called as————— –.
  15. What do you mean by loading effect?
  16. What are the practical applications of single stage CE amplifier?
  17. How do you know the amplifier is single stage CE amplifier?
  18. Why this circuit is called RC coupled amplifier?
  19. What is the operating point in CE amplifier from the design specifications?
  20. Quiescent conditions means——–
  21. C conditions are for———
  22. What is the relationship between collector current and base current?
  23. Does β and hfe are one and the same?
  24. Why coupling capacitor Cb is connected in reverse (-,+) at the input side and    Cc is connected in forward(+,-) at the output side?
  25. How do u know a transistor is working in cut off region?
  26. Write VBE(active),VBE(sat),VBE(cutoff) values of a Si and Ge transistors
  27. Transistor meaning is———
  28. Define frequency response of a CE amplifier?
  29. Define voltage gain of a CE amplifier?
  30. Units of gain as a ratio are———-
  31. Units of gain in logarithim is———
  32. Magnitude response and frequency response are one and the same say yes or no?
  33. Define bandwidth ?
  34. What are 3 dB frequencies?
  35. Define cutoff frequencies?
  36. BW is approximately equal to fH justify?
  37. Gain is constant in————-
  38. Semi logarithmic graph is linear or non linear graph?
  39. Stability factor is a function of—–
  40. In the circuit R1 and R2 are used for——–
  41. The feedback type that Re and Ce introduces in the circuit is———–(Ans: negativefeedback).
  42. Negative feedback increases stability yes or no(Ans:yes).
  43. CB amplifier provides more band width than CE amplifier justify?

TWO STAGE RC COUPLED CE AMPLIFIER:

  1. What is the need for cascading in amplifiers?
  2. Why do we need two stage CE amplifier?
  3. Why this circuit is called two stage CE amplifier?
  4. What is the relationship between gain and bandwidth?
  5. Cascading of number of stages in amplifiers increases——— –.
  6. Cascading of number of stages linear amplifiers decreases—– –.
  7. Why do we use a coupling capacitor between two stages?
  8. Why RC coupling is preferred in Audio frequency range?
  9. Explain various types of capacitors?
  10. What do you mean by loading effect? How to avoid it?
  11. Identify the stages of the amplifier?
  12. CE-CE combination is called as———-
  13. Cascade configuration means——
  14. What is the overall gain of two satge amplifier—–
  15. Is two stage amplifier is a multistage amplifier or not?
  16. Why this circuit is called RC coupled amplifier?
  17. Does CB-CB combination is possible?
  18. CE-CC combination is known as——-
  19. CB-CC combination is called as——–
  20. There exist an inverse proportionality between gain and BW yes or no?

VOLTAGE SERIES FEEDBACK AMPLIFIERS:

  1. What do u mean by feedback?
  2. What are the two types of feedback?
  3. What are the advantages of negative feedback over positive feedback?
  4. Voltage series feedback means?
  5. Input of a voltage series combination is———–
  6. Output of a voltage series combination is———–
  7. For voltage series amplifier Ri , Ro,gain and BW changes as——-
  8. How does u know the feedback is voltage series in the given circuit?
  9. What are different types of feedback topologies?
  10. Applications of voltage series amplifier?
  11. What is the difference between two stage and voltage series amplifier?
  12. Which is the best topology among four?
  13. How feedback amplifiers are different from ordinary amplifiers?
  14. Define feedback gain?

RC PHASE SHIFT OSCILLATOR:

  1.  Mention the conditions for oscillations in RC phase shift oscillator?
  2. Give the formula for frequency of oscillations in RC phase shift oscillator?
  3. The phase produced by a single RC network is RC phase shift oscillator?
  4. RC phase shift oscillator uses positive feedback or negative feedback?
  5. The phase produced by basic amplifier circuit in RC phase shift oscillator is?
  6. What is the difference between damped oscillations un damped oscillations?
  7. What are the applications of RC phase shift oscillator?
  8. How many resistors and capacitors are used in RC phase shift feedback network?
  9. How the Barkhausen’s criterion is satisfied in RC phase shift oscillator
  10. Mention the basic reason for any oscillations?
  11. What is meant by Barkhausen’s criterion?
  12. Audio frequency range is————
  13. RC phase shift oscillator is ——–
  14. Oscillator is a circuit operates on internal input power supply yes or no?
  15. Define an oscillator?
  16. Oscillator did not take any external input yes or no?
  17. Type of feedback used in oscillators is——-
  18. Radio frequency range is———–
  19. Show that single RC section provides a phase shift of 60
  20. Positive feedback causes instability yes or no?
  21. In oscillators loop gain must be————–
  22. In oscillators And overall phase shift produced by the circuit is————
  23. Feedback gain 𝛽 must be less than———–

COLPITTS AND HARTLEY’S OSCILLATORS:

  1. What are the advantages of hartley’s and colpitts oscillators over RC phase shift oscillator?
  2. Applications of C and H oscillators are—–.
  3. C oscillator uses—- as feedback network.
  4. H oscillator uses—– as feedback
  5. Define mutual inductance—–
  6. These are used at———–

MEASUREMENT OF IMPEDANCES:

  1. Differentiate symmetrical and asymmetrical networks?
  2. Define image impedance?
  3. Define characteristic or nominal impedance?
  4. Theoretical Calculations of open circuit and short circuit impedances for all the
  5. What is the significance of image impedance?
  6. Is there any difference between image and inverse impedance?
  7. Why char impedance is called as nominal impedance?
  8. Does char impedance and image impedance are same yes or no?

CONSTANT –K-LOW PASS FILTER:

  1. Define a filter?
  2. What is the difference between ordinary LPF and constant –k-LPF?
  3. Why this filter is called as constant-k-low pass filter?
  4. What does u mean by a LPF?
  5. Draw the gain characteristics of ideal and practical Low pass filters?
  6. Define attenuation? units of attenuation are——
  7. Gain and attenuation are——-
  8. Define cut off frequency of a constant k low pass filter?
  9. Draw the attenuation characteristic and explain that graph?
  10. Draw the output voltage vs frequency curve and explain it?’
  11. What are the applications of constant-k low pass filter?
  12. Advantages and disadvantages of constant k low pass filter?

M-DERIVED HIGH PASS FILTER:

  1. Define high pass filter?
  2. Define the constant m?
  3. How m derived filter is different from ordinary HPF?
  4. Why we will go for m derived filters?
  5. Draw the model graphs of m derived HPF and explain?
  6. Applications of m derived HPF?
  7. Advantages and disadvantages of m derived HPF?
  8. Define infinity frequency and cut off frequency?
  9. Are these filters are passive filters or active filters?

NOTE: read applications and advantages and disadvantages for all the circuits.

Author: Lakshmi Prasanna Ponnala

Completed M.Tech in Digital Electronics and Communication Systems and currently working as a faculty.

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