Distinguish Between Ac And Dc Signals

Published Date: 02 Nov 2017

1. Distinguish between AC and DC Signals.

2. Define Mean AC form Factor, Average and RMS values of AC Voltage and current wave forms.

3. What is meant by "Lag and Lead" of an A.C.?

4. How complex numbers can be used to represent sinusoidal signals?

5. Define root mean square of current and voltage.

RESISTORS AND RESISTANCE

1. What is a resistor? What Quantum of resistance does one ohm represent?

2. How do you find the total resistance of a) series connection of more than one resistances and b) Paralled connection of more than one resistance?

3. Distinguish between ohmic and non-ohmic resistances.

4. What does the colour band represent on carbon resistance?

5. What is ohmic law? What are its limitations?

6. What are linear and non -linear resistances?

7. Distinguish between resistance and specific resistance.

8. What does the "tolerance" specify?

9. What do you understand by temperature coefficient?

10. Distinguish between resistance, resistivity & conductivity.

INDUCTORS AND TRANSFORMERS.

1. What do you under stance by the terms "Self Inductors", "back emf", coefficients of self inductance, reactance of inductor, "Mutual inductance"?

2. Define Q-factors of an inductor.

3. State Faradays Laws of electromagnetic induction.

4. What is the principle of a Transformer operation?

5. Is a step-up transformer an amplifier?

6. What are the losses in transformer?

7. What is the relation between self inductances L1, and L2 of coils and mutual inductance between them?

8. Distinguish between "Isolation Transformer" , "Auto –Transformer" and "Variac".

9. What is Lenz’s Law?

10. What do you understand by the term electrical inertia?

CAPACITORS AND CAPACITANCE

1. What are capacitors? What is capacitive reactance?

2. What is a trimmer capacitor?

3. What is an electrolytic capacitor? How is it different from a normal paper capacitor?

4. On what factor the capacitance of a capacitor depends.

5. How instantaneous current is related to instantaneous voltage in a capacitor?

6. What is the total capacitance of number of capacitors connected in "Series" and in parallel?

7. How do you convert "Capacitors", "Inductors" and Resistors connected into "Star to delta and vice versa"?

8. What is a ganged condenser?

9. What is an ideal capacitor?

10. What is the need of electrolytic capacitor?

NETWORKS

1. Differentiate between active and passive networks components.

2. What is a node and branch in an electrical network?

3. State Kirchhoff’s Laws.

4. What are lumped elements and distributed elements?

5. What is the difference between Thevenin’s and Norton’s Theorem?

6. State:

i) Thevenin’s Theorem

ii) Norton’s theorem

iii) Superposition theorem

iv) Reciprocity theorem

v) Maximum power transfer theorem

vi) Milliman’s theorem

7. What is driving point impedance?

8. What are h-parameters?

9. What is the difference between one port and two port networks?

10. Define ABCD parameters. Where they find application and why?

11. Define Z, Y and hybrid parameters.

12. Distinguish between driving point, transfer impedance and characteristics impedances.

13. How a " network can be converted into T network and vice-versa?

14. What is a filter? Distinguish between C type, L Type and " section filters.

15. When a RC differentiator called as high pass filter?

16. How does RC circuit behave as Low pass filter?

17. What do you understand by "Transient State" and "Steady State" of an electrical circuit?

18. What are the different types of Transients?

19. What is the significance of Time Constant?

20. Distinguish between Series Resonance and Parallel Resonance? What do you understand by resonance?

21. Define the following with reference to variable resistors, Total Resistance, Resolution, Precision and Equivalent noise temperature.

22. What is smoothing factor in a choke input filter?

DIODES

1. Draw V-I characteristics of PN junction diode.

2. What is biasing? What are the different biasing techniques?

3. What is diode equation? What is the effect of temperature on diode current?

4. What is avalanche breakdown?

5. What is the Zener breakdown?

6. Draw V-I characteristics of Zener diode, Ge diode, and Si diode.

7. What is depletion region?

8. What is the Cut-in voltage?

9. What is the forward and reverse resistances of

a) Ideal diode

b) Actual diode.

10. What do you understand by the reverse saturation current of a diode? How does it vary with temperature?

11. How does the avalanche and Zener breakdown vary with temperature?

12. What are junction diodes, point contact diodes?

13. How potential barrier develops across the PN junction?

14. Define Static Resistance and Dynamic Resistance of a diode.

15. What do you understand by junction capacitance in a diode?

16. Why Zener diode is operated under reverse bias condition?

17. What is the cause of Transition Capacitance in p-n junction diode?

18. Define: Peak Inverse Voltage (PIV), or Peak Reverse Voltage (PRV), Reverse Recovery time and surge current.

19. What is step graded junction and linear graded junction?

20. How the diffusion capacitance varies with diode forward current?

RECTIFIERS

1. What is a rectifier? What are the different types of rectifiers?

2. What is the peak inverse Voltage of a diode rectifier?

3. What is PIV for a half wave and full wave rectifiers and bridge rectifier?

4. What is ripple and ripple factor?

5. What is the value of ripple factor for HWR and FWRs?

6. What is transformer utilization factor?

7. What is bleeder resistance and where is it used and why?

8. What is voltage regulation of DC power supply?

9. What are the advantages of bridge rectifier over FWR?

10. How Zener diode maintains constant voltage across the load.

11. Sketch the output waveforms of a HWR and full wave rectifier with C-type, L-type, and "type filters.

12. Define Ripple factor, rectifier efficiency, regulation, PIV.

13. What is the critical value of the filter input inductor?

TRANSISTOR (BIPOLAR TRANSISTOR)

1. Why an ordinary transistor is called bipolar junction transistor?

2. Why the base of a transistor made thin and highly doped as compared to emitter or collector?

3. Why a transistor is called current controlled device?

4. What are "emitter injection efficiency" and base transport factor? How do they affect the operation of a transistor?

5. Why silicon transistors are preferred over germanium transistors?

6. Why collector is larger than base and emitter?

7. Why emitter is always forward biased collector reverse biased with respect to the base?

8. What is dc current gain (αdc)?

9. What is β? How αdc and β are related?

10. Why is there a maximum limit of collector supply voltage?

11. Distinguish between PNP and NPN transistors.

12. What will happen to base current if a base of a transistor is made thick?

13. Why α<1 and β>1 in a transistor?

14. Why transistor will not function if the base is large?

15. Define Active region, saturation region and cutoff regions of a BJT.

16. What do you understand by cutoff frequency range, f alpha, f beta and fT?

17. What is early effect?

18. What is collector reverse saturation?

19. What is quiescent point?

20. What is punch through effect?

21. Why point contact transistors are not made?

22. What is the difference between epitaxial and diffused transistors?

23. Why CE configuration is most popular as an Amplifier circuits?

24. Which configuration gives highest input impedance but no voltage gain?

25. What is a load line? Distinguish between DC & AC load lines?

26. Sketch the input and output characteristics of BJT in CE and CC mode.

27. What the following signify: VCBO, VCEO, LCMAX, PDMAX, VEBO, Ton, Toff, hFE , hfe ICBO, ICEO, ?

28. Why in a BJT emitter is forward based and collector RB?

29. In CB configuration current gain is less than one and yet is called amplifier, why?

30. Why the resonance frequency does not depend on circuit resistance?

31. Why a series circuit called "acceptor" and parallel circuit "rejecter circuit"?

32. What is Bode’s plot? What information can be obtained from it?

33. What do poles, zeros, signify in Bode plot?

34. Distinguish between AC and DC bridges.

35. Why there should be two balance conditions in AC bridges.

36. What is bridge T-network? Why it is called so.?

37. What are the different types of bridges?

38. On what principle of cathode rays is a CRO based.

39. What is the difference between CRT and CRO?

40. What is the need of a time base in CRO?

41. Why a fluorescent screen is used in a CRO.

42. Why a deflection system used in CRO?

43. How voltage, impedance, frequency, phase and current measured by CRO.

44. What does Lissajous figure significies?

45. How do your achieve X-shift and Y-shift in CRO?

46. What are the different types of focusing techniques?

47. What are the commonly used fluorescent materials?

48. What is fluorescent and what is its importance?

49. What is the resistance of pure germanium and silicon materials?

50. Difference between metal, insulator and semiconductor.

51. What is a semiconductor? What is an intrinsic and extrinsic semiconductor?

52. What are P-type and n-type semiconductors?

53. What is doping? What is Fermi level?

54. What are drift and diffusion current in semiconductor?

55. What is life time and diffusion time?

56. What is the effect of temperature on extrinsic semiconductor?

57. What is Hall Effect? What does it signifies.

58. What is forbidden gap.

59. What is continuity equation? What does it signifies?

60. What is the effect of adding donor and acceptor impurities in a semiconductor?

61. What are conduction and valance bands in semiconductors?

62. What are the majority and minority charge carriers?

63. What is mobility and conductivity?

64. Why carbon cannot be used as semiconductor.

65. What are the types of bridges used for measuring R, L, C and complex impedances?

FIELD EFFECT TRANSISTORS

1. Why FET is called a unipolar device?

2. Why the channel of JFET is never completely closed at the drain end?

3. How is drain current controlled in a JFET?

4. What do you understand by "Drain characteristics and transfer characteristics" of a JFET?

5. Why the channel is fully open when VGS =0 and VDS =0 in a JFET?

6. What is pinch off voltage in a JFET? What parameters control it?

7. Why FET is called voltage Control device?

8. How the FET behaves for VDS Small and large?

9. How the drains current vary with the gate voltage in the saturation regain?

10. How does the Trans conductance vary with drain current?

11. What do you mean by gate-source cutoff voltage?

12. What do you mean by a saturation REGION?

13. What do you mean by drain-source saturation current (IDSS) region?

14. Why Zin of FET very high?

15. What is the value of gate-source voltage VGS that gives drain current of both P&N channel at Zero temperature coefficient?

16. What is the dynamic resistance of FET?

17. Why MOSFET is called sometimes as IGFET?

18. Differentiate between Enhancement & Depletion type MOSFET.

19. What is E-MOSFET? What is meant by gate source threshold?

20. How the threshold voltage of MOS transistor adjusted?

21. Why MOSFET should not be either connected or disconnected when power is ON?

22. Why JFET is superior to BJT?

23. Why JFET RF amplifier in receiver is used instead of BJT amplifier?

24. What are the advantages of FET and MOSFET over BJT?

25. Sketch the symbols of FET, depletion and enhancement modes of MOSFETS pertaining to N and P type channels.

26. What is a CMOSFET? What are its characteristics and features?

27. Why FETs have better thermal stability?

28. Why a FET does acts as an excellent buffer amplifier?

29. How DE-MOSFET does differ form E-MOSFET?

30. How MOSFET does differ from JFET?

a) Define π, rp and gm of a FET. What is the relation between them?

31. Define h parameters of a transistor. Why they are preferred over other parameters for the transistor circuit analysis?

32. What are the limitations of h-parameters?

33. Why a hybrid model is preferred over other models?

34. What is transistor biasing? What is mid point biasing?

35. What is thermal runway of BJT?

36. What is bias stabilization? What is stability factor?

37. State the thermal stability.

38. Why a fixed biased circuit is not commonly used?

39. Why collector to base bias is not much used?

40. Why bias compensation is used?

41. What value of α is used in the analysis of a biasing circuit?

AMPLIFIERS-SINGLE STAGE, MULTI STAGE AND LARGE SCALE AMPLIFIER

1. What is an amplifier? What is a small signal amplifier?

2. What is phase reversal?

3. What is an ac Emitter resistance?

4. What is the effect of source resistance on voltage gain of CB transistor amplifier?

5. What happens if emitter bypass capacitor is removed in a CE amplifier circuit?

6. Why CC circuits is called emitter follower? Where it is used?

7. What do you mean by frequency response of an amplifier?

8. What do you understand by power handling capacity of an amplifier?

9. Define: fT, fβ, of a BJT, gain band width product?

10. What is Miller effect?

11. What is meant by distortion in an amplifier? Why is it harmful?

12. What are the different types of distortions? How serious are they?

13. What is the effect of device capacitance in CE amplifier in high frequency region?

14. Classify amplifiers based on frequency, coupling, and mode of operations.

15. What is the need of coupling in amplifier?

16. Classify amplifiers based on conduction angle and coupling.

17. What is thermal runway with regard to amplifier? How it is minimized?

18. What is a load line? What is its significance?

19. How do you distinguish amplifiers from one-another?

20. Define: Voltage gain, Current gain, input and output resistance, Bandwidth, 3db/half power band width, power gain and slew rate with reference to amplifiers.

21. What is non linear distortion in an amplifier? Why it is called harmonic distortion? Why is it serious in case of large signal amplifiers?

22. What are inter modulation and transient inter modulation distortions?

23. What are the acceptable levels of total distortion and inter modulation distortions in a high quality audio amplifier?

24. What component limits the low frequency response of an amplifier?

25. What is the need of cascading amplifiers? What is cascading?

26. What is a multistage amplifier?

27. Which coupling schemes are used in cascaded amplifiers?

28. Which transistor configuration is most widely used in cascading of amplifiers?

29. Why over all gain of a multistage amplifier is less than the gain of the product of gains of individual stages?

30. Why Coupling capacitor provided in a self biased CE RC coupled amplifier is also called blocking capacitor?

31. Why RC Coupling does give constant gain over mid frequency.

32. Why RC coupled amplifiers are widely used as voltage amplifiers?

33. How do you improve the gain of RC coupled amplifier at low frequencies?

34. Why a bypass capacitor is used on the bottom of the each secondary winding in transformer coupled amplifiers?

35. Why coupling capacitor is not required in a transformer coupled amplifier?

36. Why direct coupling not suitable for amplifier at high frequencies?

37. What are the main characteristics of a Darlington amplifier?

38. What are the main characteristics of a cascaded amplifier?

39. Why do we need more than one amplifier in practical circuits?

40. Why are amplifiers coupled?

41. What is the advantage of using transformer to cascade transistor amplifiers?

42. What is the effect of cascading on the bandwidth of an amplifier?

43. What is meant by power amplifier? Why are they called large signal amplifiers?

44. Why a power amplifier is always preceded by voltage amplifier?

45. What is the power dissipation capacity of a power amplifier?

46. What are different types of power amplifiers? Define.

47. Why a class a power amplifier is cooler in the presence of signal then the absence of a signal?

48. What is maximum collector circuit efficiency of transformer coupled class a amplifier?

49. Why step-down transformer is used in the output circuit of a power amplifier?

50. What is the maximum efficiency of class B amplifiers?

51. What is the use of class C amplifiers?

52. Why class D power amplifiers are becoming more and more popular.

53. What is the maximum collector circuit amplifier of a complementary push-pull power amplifier?

54. Define: thermal resistance of power transistors.

55. Why heat sink is needed in power amplifiers?

56. Distinguish between class A, Class B and Class C, power amplifiers.

57. Why do you call a power amplifier a dc power amplifier or frequency convertor amplifier?

58. Distinguish between power amplifier, voltage amplifier and current amplifier.

59. What is meant by dc-rating factor of a power transistor?

60. What is a push-pull amplifier?

61. What is cross over distortion?

62. Why feed back needed in amplifier?

63. What is the difference between current and voltage feedback?

64. How does series and shunt feedback differ from each other?

65. Why voltage series feedback most commonly used in cascaded amplifiers?

66. What are the different types of feedbacks?

67. What is the effect of negative feedback on amplifier gain & bandwidth?

68. What is the effect of negative feedback on the input impedance?

69. Whether the input impedance of a voltage series feedback amplifier increases or decreases with negative feedback?

70. What is the effect of removing bypass capacitor across the emitter resistor in case of a CE amplifier?

71. What is the effect of negative feedback on the input and output impedances of a voltage series feedback amplifier?

72. What are the advantages of negative feedback in amplifiers?

73. What is the disadvantage of positive feedback in a single stage amplifier?

74. What type of feedback is used in common emitter amplifiers?

75. What are the advantages and disadvantages of negative feedback?

76. What percentage of feedback is present in an emitter follower?

OSCILLATORS

77. What is an Oscillator?

78. What is the initial condition for oscillators to start?

79. What is the Barkhausen condition of Oscillations?

80. Can Oscillator be an amplifier with an infinite gain?

81. Why are LC resonant circuits impractical at audio frequency?

82. How does Hartley oscillator differ from colpits oscillator?

83. Why two transistors are in Wein Bridge audio oscillator?

84. How does a signal generator differ from an ordinary oscillator?

85. How does an oscillator differ from an amplifier?

86. Why a negative feedback amplifier cannot function as an oscillator?

87. What is the basic principle of RC phase shift oscillator?

88. Why RC oscillators are preferred at audio frequency range?

89. Why negative feedback, in addition to the positive feedback is employed in wein bridge oscillator?

90. What are basic types of oscillator?

91. What are the important factors in choosing a certain type of oscillator?

92. Why do we use 3 RC sections in phase shift oscillator?

93. What factors are responsible for frequency variation in an oscillator?

94. How the frequency of an oscillator is stabilized?

95. What are multi vibrators? What are the different types of multi vibrators?

96. What is relaxation oscillator?

97. What are the different types of sinusoidal oscillators?

ELECTROMAGNETIC THEORY

1. Differentiate between circuit theory and field theory.

2. What is scalar product and vector product?

3. State: Gauss theorem, Strokes theorem, close and open surfaces, line integral, surfaces integral and volume integral, divergence theorem.

4. What is coulombs law?

5. What is an electric field? What is its unit?

6. What is an isotropic medium?

7. What is electric displacement density?

8. State Laplace’s and Poisson’s equations.

9. What are equipotential surfaces?

10. Differentiate between electric dipole and electric dipole moment.

11. State Ampere’s Law and Faraday’s Law.

12. State Maxwell’s Equations in differential forms and integral forms.

13. Define: Magnetizing force, Magnetic flux density, magnetic permeability.

14. State Biot-Savart law.

15. Define: Poynting’s theorem, Brewster’s angle.

16. What is Ampere’s circuit law?

17. What is boundary condition? State E&H boundary conditions.

18. What is a source free medium?

19. What is a wave equation? Write the solution.

20. What is wave polarization?

21. What is linear, circular, and elliptical, cross polarization, orthogonal polarization?

22. What is loss tangent?

23. What is skin depth?

24. What is the meaning of complex permittivity?

25. What are phase velocity, group velocity and wave length?

26. What is refractive index of a medium?

27. What is dispersion?

28. What is surface current?

29. What is intrinsic impedance? What is its value in terms of µ and ε?

30. Distinguish between conduction and displacement currents.

31. What is a plane of incidence?

32. Define: angle of incidence, reflection and refraction.

33. What does perpendicular and parallel polarization mean?

34. What are reflection and transmission coefficients?

35. What is total internal reflection?

36. What is the difference between TIR and ordinary reflection?

37. Why Brewster angle also called as polarizing angle?

WAVE GUIDE

1. What is a waveguide?

2. What is a parallel plane waveguide?

3. What are TEM, TE and TM modes?

4. What is cut off frequency, dominant mode?

5. What is wavelength, guide wavelength and cut off wave length?

6. Why a TEM mode cannot propagate in a waveguide?

7. How vg, vp, and vo, Zwg, Zo related to each other?

8. What is attenuation?

9. How EM waves propagate through wave guides?

10. What are microwave frequencies?

11. What are the advantages of microwaves?

12. What are the applications of Microwave frequencies?

13. What is Circular waveguide?

14. What are the different power losses in a waveguide?

15. Differentiate between strip line and micro strip line.

16. What do you understand by effective Dielectric constant?

17. What are S-parameters? List the properties.

18. What is a cavity resonator? How they are excited?

19. What are microwave hybrid components?

20. What are directional Coupler, E-plane Tee, H-Plane Tee, Magic Tee, Circular, Gyrator, Isolator, Windows, and Irises?

21. What are attenuators? Why are they required?

22. State the principle of working of a frequency meter.

23. What are the limitations of conventional vacuum tubes?

24. What is transit time and transit angle?

25. What are bunching and de bunching of electrons in microwave tubes?

26. What is velocity modulation and current modulations?

27. What are ferrites? State faradays rotation phenomenon.

28. What is slow wave structure? Why it is needed?

29. Why Ga As is superior to Si at microwave frequencies?

30. What is the difference between bulk and junction effect semiconductor?

31. What are the Gunn diode operating modes?

32. What is Helmholtz wave equation?

33. What are O-type and M- type, of microwave tubes?

MICROPROCESSOR AND MICROCONTROLLER

1. What’s Microcontroller?

2. What are the features of 8085 and 8086?

3. What is a flag register in 8085?

4. What is the control signals used in 8085?

5. What is ALE signal?

6. What is the use of CLKOUT and RESETOUT signals of 8085 processor?

7. Define Instruction cycle, machine cycle, and T state.

8. What is the memory read and write cycles of 8085?

9. What is the I/O read and write cycles of 8085?

10. What do you understand hardware interrupt and software interrupt?

11. What are vectored, INTR, Pending interrupts?

12. What is pipelining? Classify and compare.

13. What are segment, pointer, index addressing?

14. What is sting addressing mode?

15. What is base relative plus index addressing?

16. What is short, near and far jumps?

17. What is stack? What is the function of stack pointer?

18. What is indirect program memory addressing?

19. What is the function of assembler directives?

20. Distinguish between M/C program and Assembly language program.

21. What is debugger? List debugger commands?

22. What is micro?

23. What are maximum and minimum mode signals of 8086?

24. What do you mean by input and output port?

25. Distinguish between mode set control word and BSR control word of 8255.

26. What are entropic interface and printer interface?

27. What do you mean by static display and multiplexed display?

28. Differentiate between encoded and decoded scans.

29. What is transistor buffer circuit?

30. What do you mean by interrupt, interrupt vector tables?

31. What is interrupt service routine?

32. What are software interrupts?

33. What are interrupt priorities?

34. Distinguish between master and slave mode operations of 8259.

35. What is dividing by Zero Interrupt, Single Step Interrupt, and Break Point Interrupt over flow interrupt?

36. Distinguish between vectored interrupt and non-vectored interrupt.

37. What is the need of DMA in microprocessor?

38. What is a microprocessor?

39. Compare parallel and serial type o f data transfer.

40. What is RS 232c protocol?

41. Differentiate between synchronous and non synchronous formals.

42. What are the different types of microcontroller?

43. What is the difference between microprocessor and microcontrollers?

44. What is jumps range?

45. State the importance of RI flag bit & TI flag bit.

46. What is key bounce? How it is achieved?

47. State the features of AVR family.

48. List the features of at 90S2313 microcontroller.

DIGITAL SIGNAL PROCESSING

1. What are the basic elements of DSP?

2. What are the merits and demerits of DSP over Analog signal processing?

3. State the advantages and disadvantages of digital processing of signals.

4. What are the applications of DSP?

5. What is a signal? What are the different types of signals?

6. What is the condition for periodicity of discrete time signal?

7. Distinguish between multi channel and multidimensional signals.

8. What is a singularly function?

9. What is a discrete time signal? What are the different types of DTS?

10. What are the different signal processing operations?

11. Define linearity, time variance, stability and causality of a system.

12. State the properties of convolution.

13. What are recursive and non recursive systems?

14. What are FIR and IIR systems?

15. State sampling theorem? What is Nyquist sampling theorem?

16. What is Nyquist rate and Nyquist interval?

17. Define DFT and IDFT.

18. List the properties of DFT.

19. State circular convolution and convolution frequency shift property of DFT and complex conjugate property.

20. State Parseval’s theorem.

21. State circular time shift, circular frequency shift and modulation properties of DFT.

22. What is linear filtering?

23. What are the overlap save ad overlap add methods of long sequence filtering?

24. State the different properties of Twiddle factor.

25. State FET algorithms.

26. What are the properties of ROC-region of convergence?

27. Define Z-transform, DTF and its inverse.

28. What is stable and unstable system?

29. Draw the basic structure of FIR system.

30. Compare analog & Digital filter advantages & disadvantages.

31. What are even and old signals?

32. Define: Deterministic signal, random signals, causal and non causal signal.

33. What is under sampling? What are its effects?

34. What is aliasing? How can it be avoided? What is a pre-alias filter?

35. What is a difference equation?

36. What is lattices structure? What are its advantages?

37. What is dirichlet condition?

38. Is DFT a linear transform?

39. What is radix -2?

40. What is a buffer fly operation?

41. What is signal flow graph?

42. Can pole and Zero lie on the same point?

43. What is Gibb’s phenomenon? How can it be reduced?

44. What is transition? What is its ideal value?

45. What is the difference between MATLAB and C programming magnitude and phase plots?

46. What is a window? How is it selected? List its characteristics.

47. Why windowing necessary?

48. What is a prewarping?

49. What is an ideal low pass filter? Can it be designed?

50. Is it possible to have IIR filter without poles or without zeros.

51. When can a stable analog filter be converted into digital filter?

52. What is DTMF? Does DTMF tones are stationary or no stationary?

53. Is a DEP processor a microprocessor?

54. What is spectrogram? List its application.

PROBABILITY, RANDOM VARIABLES & RANDOM SIGNAL PRINCIPLES

1. What do understand by the terms: Set, finite set, null set, subset, equal sets, difference sets?

2. Define union and intersection of two sets.

3. What is a complement of a set?

4. What is the D ‘Morgan’s laws?

5. What is duality principle, discrete and continuous sample spaces?

6. What is probability? Define probability as a relative frequency.

7. What is a joint and conditional probability?

8. What do you understand by total probability?

9. State Baye’s Theorem.

10. What is an independent event? List its properties?

11. What do you understand by permutation and combination?

12. What is Bernoulli?

13. What is random variable? Under what condition a function is random variable?

14. What are discrete, continuous and random variables?

15. What is cumulative probability, distributive function and density function of a random variable?

16. List the properties of a density function.

17. What is Gaussian random variable? What are its properties?

18. Define: Conditional distribution and conditional density.

19. What are the properties of conditional density?

20. What is expectation? What is the expected value of a random variable?

21. What is conditional expect value?

22. What is a moment? What are the functions that give moment?

23. Distinguish between Chebychev’s inequality and Markova’s inequality.

24. How one random variable can be transformed into another random variable?

25. Define arcsinc probability density, and Poisson’s random variable.

26. What is binomial density?

27. What is chi-square density?

28. What is vector random variable?

29. What do you understand by joint distributions? List its properties.

30. Define joint density. List its properties.

31. State central limit theorem

32. What is Equal and unequal distribution?

33. Define multiple (vector) random variables.

34. What is statistically independent random variable?

35. What are week and strong laws of large numbers?

36. What is the random process? How it is classified?

37. Distinguish between deterministic and non deterministic processes.

38. Define auto correlation, cross correlation, auto covariance, cross covariance and sequence.

39. How the correlation functions are measured?

40. What are power density spectrum and voltage density spectrum?

41. What are the properties of power density spectrums?

42. How the power spectrum and auto correlation functions are related?

43. What is cross power density spectrum? List its properties.

44. What is the relation between cross power spectrum and cross co-relation function?

45. What is the power spectrum for discrete time process and sequences?

46. What is a linear system?

47. What is a linear time invariant system and idealized system?

48. What is causal and stable system?

49. What are band pass and band limited and narrow band processes?

50. What are discrete time systems?

51. What is noise? What are the different types of the noise?

52. What is statistically random variable?

TRANSMISSION LINE

1. What is a transmission line?

2. What is characteristic impedance? What does it signify?

3. What is a standing wave? Why does it occur on a transmission line?

4. What are voltage and current reflection coefficients?

5. What is impedance transformation?

6. What are the basic types of transmission line?

7. What are different types of transmission lines?

8. What are the lossless and low losses transmission lines?

9. State the condition for a distortion less transmission line.

10. What is loading? What is the need of loading a transmission line?

11. What is standing wave ratio? What is its range?

12. What is the relationship between reflection coefficient and VSWR?

13. What is the impedance at voltage maximum and minimum?

14. What is a matched load? Why is it important?

15. What is a Smith chart?

16. What is the difference between impedance and admittance Smith chart?

17. What are quarter wave length transformers?

18. What is stub marching? Why it is required?

19. What are the drawbacks of a single stub matching?

20. What is double stub matching? What are its advantages?

21. What is a lossy transmission line?

22. Why impedance (admittance) be normalized before being plotted on a standard Smith chart?

23. List three functions of transmission line.

24. What are the deferent methods of impedance matching?

25. What are primary parameters of a transmission line?

26. Define the primary parameters of transmission line.

27. Distinguish between lumped and distributed parameters of a transmission line.

28. What are the secondary constants? What is the relationship between the primary and secondary parameters of a transmission line?

29. Define attenuation constant, propagation constant and phase constant.

30. List the transmission analogy for a wave guide.

WAVE PROPAGATION

1. What do understand by wave propagation? On what basis it is classified.

2. What is meant by ground wave, space wave and sky wave propagation?

3. What is "Line of Sight" of propagation?

4. Why ground wave propagation cannot be used at high frequencies?

5. On what parameters the mode of propagation depends.

6. What is troposcatter?

7. On what parameters the mode of propagation depends.

8. List the properties of D, E, F1, F2 and sporadic E layers.

9. What is ionospheric propagation?

10. What is space wave propagation?

11. Define fading, maximum usable frequency (MUF), Gyro frequency, Dellinger Fade-out, skip distance, multiple-hop.

12. What is duct propagation?

13. What is the effect of earth’s magnetic field on ionospheric propagation?

14. What is critical frequency and critical angle?

15. Define virtual height, whistlers, optimum usable frequency.

16. What are the major causes of fading?

17. What is radio horizon?

18. Distinguish between galactic noise and atmospheric noises.

19. What are the merits and demerits of multihop transmission?

20. State Snell’s law for refraction.

21. Distinguish between wave length and wave front.

22. What is Huygens principle?

23. What is fading margin?

24. Define electromagnetic wave interference.

25. What is escape ray?

26. What is wave attenuation and absorption loss?

27. What is path loss and absorption loss?

28. What is a primary and secondary coverage area?

29. What are earth constants?

30. What is the effect of curvature of the earth on the propagation?

31. What is lowest usable frequency?

32. What are atmospheric abnormalities?

33. What is the significance of modified refractive index?

ANTENNAS

1. Define an antenna, near field, far field, front to back ratio, antenna beam width, bandwidth, radiation resistance, gain, directive gain, directivity, polarization.

2. What is anisotropic antenna? What is gain and aperture area?

3. Distinguish between hertzian dipole and half wave dipole.

4. What are the gain and aperture areas of hertzian and HWD?

5. What is the effect of earth on the antenna radiation pattern?

6. Define antenna impedance, top loading, polarization, unidirectional antenna.

7. What is an antenna array? Why it is required?

8. What is meant by parasitic element and driven element?

9. Distinguish between resonant and non-resonant antenna.

10. Define BSA and EFA and compare them.

11. What is folded dipole antenna? What its radiation resistance.

12. What is a yagi-uda antenna?

13. What is a loop antenna? What is its radiation resistance?

14. What is a helical antenna? What are modes of radiation?

15. Define main lobe, side lobe, side to side coupling, and back to back coupling.

16. How a parabolic reflector operates?

17. What is a horn antenna? What are the different type’s of horns?.

18. Why horn antenna is preferred as a feed for parabolic antenna?

19. Why half wave dipole is unsuitable as feed for a parabolic antenna?

20. Distinguish between field pattern and power pattern of an antenna.

21. What is pattern multiplication method? What are its advantages?

22. What is a binomial array? What are its advantages?

23. Define effective length, effective aperture area.

24. State antenna theorems.

25. What is an antenna feed line?

26. What is an image antenna?

27. Distinguish between Marconi and hertzian dipole antenna.

28. What are the advantages of BSA over collinear antenna array?

29. Define phased array, reflector, director of an antenna.

30. What is the effect of shape change on antenna impedance, beam width & and radiation?

31. State Helmholtz’s wave equation.

32. What is the relation ship between gain and effective area of an antenna?

33. What is beam solid angle, HPBW and BWFN?

34. What is a resonant antenna?

35. What is the gain of a small loop antenna?

36. What are the functions of an antenna?

37. What are the properties of an antenna?

38. What is retarded potential? Explain.

39. Define radiation intensity, short magnetic dipole.

40. What is a travelling antenna?

41. What is a rhombic antenna? List its properties & advantages & disadvantages.

42. What is a cassegrain antenna? What are its advantages?

43. What is the significance of f/D ratio in a parabolic reflector?

44. What is a lens antenna?

45. What are the different types of lens antennas? Compare them.

46. What is zoning? What are its advantages?

47. What are the precautions to be taken during antenna measurements?

48. What is friis equation?

49. What are the different methods of gain measurements?

50. What is a micro strip antenna? What are its advantages?

SWITCHING THEORY & LOGIC DESIGN

1. What do you understand by switching theory?

2. What do you mean by Logic?

3. What are the advantages of digital electronic technology?

4. What are the salient features of signmagnitude method?

5. What are the salient features of a) 1’s compliment, b) 2’s compliment method?

6. Define word length, over flow error.

7. What are the rules of BCD addition?

8. What are alphanumeric codes?

9. What are the merits of digital system?

10. Define resolution and accuracy.

11. Distinguish and define:

i) Weighted and non weighted codes.

ii) Sequential and Non-Sequential codes.

iii) Reflective and Non-reflective codes.

12. What is a self complementary code? What are its advantages?

13. What are gray codes? What are its advantages significance?.

14. What are logic gates?

15. State the principle of duality.

16. What do you understand by enabling and disabling gates?

17. What are universal gates?

18. What are the properties of XOR gates?

19. State associative laws. What is its importance?

20. What is the difference between OR and XOR gates?

21. State the postulates used in Boolean algebra.

22. State DeMorgan’s theorem. What is its significance?

23. State distributive laws and their significance.

24. What are the demerits of algebraic method of minimization?

25. What is a K-map? What are the different types of K-maps?

26. Define implicant, Prime implicant, Essential Prime implicant, selective implicant, and redundant prime implicant.

27. Distinguish between combinational and sequential circuit.

28. What are half adder and full adders?

29. What are half and full sub tractors?

30. Distinguish between ripple carry adder and look a head carry adder.

31. Define decoder, magnitude comparator, encoder, Shannon’s expansion theorem.

32. Distinguish between programmable logic array PLA) and programmable array logic (PAL).

33. Compare and contrast ROM, PLA, and PAL.

34. Define clock. What are the features of clock?

35. Define Flip Flop, Register, shift Register.

36. What is race-around condition?

37. What is a counter? How are counters classified?

38. What do you mean by modulus counter?

39. Define universal shift register and bidirectional shift register.

40. What is the ring counter?

41. What is a pulse strain generator?

42. What is a finite state machine?

43. What are Mealy and Moore machines?

44. Define state equivalence, setup time, hold time.

45. Define merger graph, implication chart, and compatible states.

46. What is a ASM chart? What are its primary components?

47. What are the salient features of ASM chart?

48. What are data paths?

49. What do you understand by one flip flop per state method of state assignments?

50. What are the advantages of one flip flop per state method?

ANALOG COMMUNICATIONS

1. Define communication. Draw a block diagram of a basic communication system.

2. What is mean by noise? What are the different types of noise?

3. What is base band?

4. What is base band transmission? What is its limitation?

5. What is modulation? What are the different types of modulation?

6. What are the advantages of modulation?

7. Define modulation index, and percentage modulations.

8. How AM can be expressed in time domain and frequency domain?

9. Write the equation for power transmitted in terms of carrier power and side band power.

10. What do you understand by multy tone modulation?

11. How an AM signal can be generated?

12. What is an envelop detector?

13. What is design clipping? How it can be avoided?

14. What do you mean by distortion? What are the different types of distortions?

15. Distinguish between double side band, single side band, DSB-SC, SSB-SC, and vestigial side band, pilot carrier.

16. What is a balanced modulator? What are its advantages?

17. Define coherent detection and non-coherent detection in a receiver.

18. What are the carrier requirements for a radio transmitter?

19. What are the different types of radio receivers?

20. What are the low level and high level modulation?

21. How do you classify radio transmitters?

22. Draw a typical block diagram of a radio transmitter.

23. Draw a typical block diagram of radio receivers.

24. Differentiate between direct and indirect modulation.

25. What is automatic frequency control?

26. What is frequency modulation?

27. What is modulation index of a FM.?

28. What is SSB modulation? Why it’s necessary?

29. What are the advantages and disadvantages of SSB modulation?

30. Why vestigial side band modulation required? What are its advantages?

31. Define phase modulation and angle modulation.

32. What do you mean by narrow band and wide band modulations?

33. Define frequency deviations ratio.

34. Compare AM, FM, and PM.

35. What is a slope detector?

36. What is an amplitude limiter?

37. Define capture range, and lock range of a PLL circuit.

38. Define signal to noise ratio, noise figure, pre-emphasis and de-emphasis.

39. What is a function of RF amplifier in a receiver?

40. What are the advantages of super heterodyne receiver?

41. What are the receiver characteristics? Define them?

42. What is image frequency? How it is rejected?

43. How the intermediate frequency is selected?

44. What is automatic gain control? What are the different types of AGCS?

45. What are the merits of delayed AGC over simple AGC?

46. What is a mixer? What is its function?

47. Why tracking is used in a receiver?

48. Why local oscillator frequency is more then the incoming signal frequency?

49. State sampling theorem.

50. What is aperture effect?

51. What is PAM? What are the merits and de-merits off PAM?.

52. What is single polarity and double polarity PAM?

53. What is pulse width modulation? What are its advantages and disadvantages?

54. Distinguish between PAM, PWM, and PPM.

55. What is multiplexing? What are the different types of multiplexing?

56. Compare different multiplexing techniques.

57. Sate Hilbert transform. What are its properties?

58. What is the need of modulation?

DIGITAL COMMUNICATIONS

1. What is quantization?

2. What are M-array coding techniques? State its advantages.

3. Compare analog and digital communications.

4. State Shannon-Hartley theorem.

5. State the signification of BW, Signal to noise ratio, trade of Gaussian channel.

6. State sampling theorem for band pass signals.

7. What is µ-law and A-law?

8. What is Pulse Code Modulation?

9. What is Delta Modulation? Compare with PCM.

10. How the noise effect delta modulation?

11. What is granular noise?

12. What are the advantages of Adaptive Delta Modulation over Delta Modulation?

13. Compare PCM and ADM.

14. What is a maximum power that can be transmitted without slop overload distortion?

15. Compare the different noise in PCM and DM.

16. What are the advantages and disadvantages of digital modulation?

17. Define ASK, PSK, BPSK, DPSK and state their advantages and disadvantages.

18. What is QPSK signal? What are its advantages and disadvantages?

19. Compare QASK, QPSK, BFSK and coherent BFSK.

20. What is intersymbol interference (ISI)?

21. What is a Matched filter? What are its properties?

22. What is the need of matched filter?

23. What is a correlation receiver?

24. What is cross talk? How it can be eliminated?

25. What are the fundamentals of information?

26. Define information and state its properties.

27. What is entropy? Classify them and define.

28. What is a memory less channel?

29. Define channel capacity.

30. What is mutual information?

31. What is MPEG, JPEG?

32. What are Hamming Codes?

33. What are Huffman Codes?

34. What do you mean by block size and linear block size?

35. What are cyclic Codes?

36. State viterbee algorithm.

37. What is direct sequence & spread spectrum techniques?

38. What is processing gain and jamming nongain?

39. Distinguish between instantaneous, natural and flatlop sampling techniques.

40. What is quadrature sampling of band pass signals?

41. What are the different types’s of quantizers?

42. Distinguish between uniform and non uniform quantizer.

43. What is LimpleZiv algorithm?

44. What s linear predictive coding?

45. What is multiple and code executive LPCS?

46. What is transversal equalizer?

47. What is duo binary & modified duo binary signaling?

48. What is split phase signaling?

49. What are Baker’s signals?

50. Distinguish between multiplexing and multiple accesses.

51. What is inverse multiplexing?

52. Compare bit and byte interleaving.

53. What are random errors and burst errors?

54. Distinguish between block codes and convolution codes.

55. What are viterbi decoders?

56. What are cyclic codes?

57. What is PN sequence?

58. What are the properties of MLsequences?

59. What is direct sequence spread spectrum (DSS) Systems?

ELECRONICS MEASUREMENTS AND INSTRUMENTATION

1. What are the objectives of measurement?

2. What are the advantages of instrumentation systems?

3. Define an instrument and performance characteristics.

4. What are the different types of errors in measurements? List them.

5. What do you understand by dynamic characteristics of an instrument?

6. Compare the static and dynamic characteristics of instrument.

7. What are the standards of measurements? Define them.

8. What are the principles of working of:

a) Suspension Galvanometer

b) DC Voltmeter

c) Multirange voltmeter.

9. Distinguish between DC and AC meters functioning.

10. What do you understand by loading effect in ammeters?

11. What is a differential AC voltmeter?

12. What is the principle of ohmmeter? Classify them.

13. What is the reason for electrolytic capacitor leakage current? How this current can be reduced?

14. How the range of measuring instrument can be extended?

15. What is frequency compensation?

16. Distinguish between active and passive instruments.

17. What are the primary and secondary standards of:

a) Resistors

b) Inductors

c) Capacitors

18. What are

a) Null/ Deflection instruments

b) Monitoring / control instruments

c) Analog/ Digital instruments

19. What do you understand by

a) Hysteresis

b) Dead space

c) Threshold

d) Resolution

20. What are the parameters to be considered in the choice of instruments while measuring?

21. Differentiate between indicating, recording and integrating instruments.

22. What is meant by the terms "damping" and "Control"?

23. Why is damping mechanism provided in electrical measuring instruments?

24. Why are instruments provided with leveling screw?

25. What are the principles of D’Arsonval Galvanometer operation?

26. What is the principle of an electrodynamometer?

27. What are the essential subsystems of an electronic DC voltmeter and AC voltmeter?

28. What is a VTVM? List its advantages & disadvantages.

29. What are wave analyzers?

30. What are the different types of wave analyzers?

31. What are the factors to be considered for procuring a spectrum analyzer? What are its applications?

32. What for a power analyzer is used? What features it has?

33. Distinguish between oscillator, testoscillator and signal generators.

34. What features to be considered in selecting an oscillator?

35. What do you understand by the term "Bridge"?

36. What are the basic bridges? Compare them.

37. What is the significance of bridge circuit measurement over direct meter measurements?

38. What is the limitation of a wheat stone bridge? List its applications.

39. How the Kelvin bridge over comes the limitation of wheat Stone Bridge.?

40. Why a Kelvin bridge is called "double bridge".

41. What are the different types of detectors used in AC bridges?

42. What does the dissipation factor of a capacitor signifies?

43. What is cathode Ray oscilloscope (CRO)? What for it is used?

44. What is the difference between cathode tube and CRO?

45. How a applied signal displayed on the screen of a CRO?

46. Can voltage and current be measured using CRO?

47. Define deflection sensibility of a CRO.

48. Compare analog and digital storage CRO’s.

49. What are the various applications of CRO’s?

50. What are the essential subsystems of a CRO? List them.

51. List the steps for operating a CRO.

52. What is a Lissajous figure? How can it be used to measure phase, frequency and time period?

53. What are the advantages and disadvantages of dual trace CRO?

54. What are the different types of CRO probes? List their applications.

55. What is the principle of sampling oscilloscope?

56. What is the principle on which time Base generation circuit operate?

57. What is a chart recorder? What are its disadvantages?

58. What are the different types of recorders? Compare them.

59. What is the maximum sensibility of a Dual Trace Oscilloscope?

60. How the high frequency operation of an oscilloscope can be improved?

61. What type of dielectric material is used in storage CRT?

62. What is a transducer? How are they classified?

63. What are the factors that affect the performance of transducers?

64. Distinguish between active and passive transducers.

65. How the error due to loading effect can be estimated in is potentiometer transducer?

66. Define linearity, resolution and noise in potentiometer transducers’.

67. How the gauge factor expressed for strain gauge transducer?

68. What are the advantages and disadvantages of resistance thermometers?

69. What is the principle of working of a resistance thermometer?

70. What is a semiconductor train gauge? How it works?

71. What is LVDT? What is the principle of working of LVDT?

72. What are the applications of LVDT?

73. What are magneto strictive transducers? What are the errors in it?

74. State the laws of thermocouple.

75. What is the principle of working of a variable capacitor transducer?

76. What is a piezoelectric transducer? What are its coefficients?

77. Define gauge factor.

78. What is the principle of dummy strain gauge?

79. What are the principles of working of various anemometers?

80. What are the different methods for the measurement of electrical and non-electrical temperature?

81. How flow measured? What are the characteristics of flow meters?

82. Compare analog and digital data acquisition systems.

83. What are the advantages of electromagnetic flow meters?

84. How humidity and moisture measured? Differentiate them.

85. How the vacuum levels are measured?

86. Explain the working principles of piston type area meter?

87. List the salient features and applications of laser Doppler anemometers.

88. How the effect of eddy current can be reduced?

SIGNALS AND SYSTEMS

1. What is a signal? Classify them.

2. What is system? Classify them.

3. Distinguish between deterministic signal and random signal with suitable examples.

4. Define periodic and aperiodic signals with examples.

5. What are even and old signals? Give examples.

6. Distinguish between energy and power with suitable examples.

7. Define: unit impulse, step signal and ramp signal.

8. Differentiate between linear and non-linear signals.

9. What is a linear time in variant (LTI) system?

10. What are the memory properties of a signal?

11. What are causal and non causal systems? Give examples.

12. What are the properties of impulse, ramp and step signals?

13. What are the elementary signals? Classify them.

14. What is an auditory system? What are its functions?

15. What are the advantages and disadvantages of analog and digital signal processing?

16. What are the operations performed on dependent variables? Explain.

17. What are the properties of a system? Discuss.

18. What are the operations performed on an independent variable?

19. Discuss the following properties of linear time invariant systems: commutative, Associative, stability, causality and Distributive.

20. What are the differences between continuous time and discrete time LTI systems?

21. What is convolution integral for discrete time signals?

22. What is convolution sum for discrete time signal?

23. What is the dirichilet’s condition for Fourier series?

24. What is the Fourier series representation of a periodic signal in trigonometric form?

25. What is the concept of negative frequency?

26. What is the difference between Fourier transform and Laplace transform?

27. What is the linearity and time scaling properties of Fourier transform?

28. What is the time sifting and frequency shifting properties of Fourier transform?

29. What is convolution? State time convolution and frequency convolution theorems.

30. State Parseval’s theorem for energy signals.

31. Differentiate between power and energy spectral densities.

32. State the analogy between vectors and signals.

33. Define discrete Fourier transform and inverse discrete Fourier transform.

34. What is the difference between continuous time Fourier transform and discrete Fourier transform?

35. What do you understand by the term periodicity of discrete time Fourier transforms?

36. State time shifting and frequency shifting property of discrete time Fourier transform.

37. State frequency differentiation property of DTFT.

38. State conjugate property of DTFT.

39. What is inverse Fourier transform? Give examples?

40. Define frequency response of linear time invariant system.

41. What do you mean by linear and non linear phases?

42. What are the time domain properties of ideal frequency selective Filters?

43. What are the time domain and frequency domain aspects of non ideal filters?

44. State the sampling theorem in time domain.

45. What is the function of low pass filter in sampling?

46. Define Z-transform. What is its usefulness?

47. What is region of convergence (ROC) of Z transform? List its properties.

48. What is the condition for Z=transform to exist?

49. What is two sided Z-transform?

50. State the shifting property of Z-transform?

51. State the shifting and final value theorem of Z-transform.

52. What is the convolution property of Z-transforms?

53. Define: inverse Z-transform.

54. Discuss: scaling property, differentiation property, time reversal and linear property of Z-transform.

55. Distinguish between convolution and correlation of signals.

56. What is correlation? List its property.

57. What is autocorrelation? What are its properties?

58. What is the relation between autocorrelation function and energy spectral density and power spectral density?

59. Define Laplace transform.

60. What is the condition for the existence of Laplace transform?

61. What are the properties of Laplace transform?

62. What is unilateral Laplace transform? What are its properties?

63. What are the important singularity functions? Why are they employed in circuit and system analysis?

64. What is switched time periodicity?

65. What is the relation between Laplace transform and Fourier transform?

66. What do you understand by natural sampling and flattop sampling?

67. What is band pass sampling?

68. What is bilateral Laplace transform?

69. Differentiate between combination logic and sequential logic.

70. What are the differences between synchronous and asynchronous sequential logic circuits?

71. What is wave forming?

72. What is the difference between the output from clipping circuit and clamping circuit?

73. What is the difference between a positive clamping and negative clamping circuit?

74. What are voltage doublers? What are the draw backs of full wave voltage doublers?

75. How is an electronic switch superior to mechanical switch?

76. What is a function generator?

77. What is a switching circuit?

78. What is a hard saturation?

79. Define: Time base, sweep voltage, sweep speed errors, displacement error and transmission error.

80. Differentiate between Miller sweep and Miller Bootstrap circuit.

PULSE AND DIGITAL CIRCUITS

1. What are linear and non-linear Networks?

2. What is linear wave shaping? Give examples.

3. What is a non-linear wave shaping? Give examples?

4. How the RC circuit acts? Is it a low pass filter?

5. What is a differentiator circuit?

6. Justify that RC differentiator circuit is high pass filter.

7. How does the RL circuit acts as an integrated?

8. What are clipping and clamping circuits?

9. State whether clipping and clamping circuit are linear wave shaping or non-linear wave shaping circuits.

10. What are the advantages and disadvantages linear wave shaping circuits using RC and RL components?

11. What is a ringing oscillator?

12. What is a multivibrator? How are they classified?

13. List the applications of the multivibrators.

14. Which multi vibrator functions as a time delay unit and Why?

15. Which multivibrator would be useful for

a) Harmonic generation of square waves.

b) Time delay unit

c) Memory device

d) Frequency division

16. What is a-Schmitt trigger? How is it different from multivibrat