Viva - Voce Questions

  Linear circuits:

  1. Mention the advantages of integrated circuits.
  2. Write down the various processes used to fabricate IC’s using silicon planar
  3. What is the purpose of oxidation?
  4. Why aluminum is preferred for metallization?
  5. What are the popular IC packages available?
  6. Name the parameters which govern the thickness of the film in the oxidation process.
  7. What do you mean by monolithic process?
  8. List the advantages of integrated circuits over discrete component circuit
  9. What are various steps involved in basic planar process of IC fabrication.
  10. What are the limitations of integrated circuits?
  11. What is the advantage of using dry etching process?
  12. What is meant by epitaxial growth?
  13. What are the advantages of ion implantation technique?
  14. What is ion implantation?
  15. Name the different types of IC packages.
  16. Classify IC’s based on the fabrication.
  17. Give reason for selecting SiO2 for oxidation process in IC fabrication.
  18. Define an operational amplifier.
  21. Mention the characteristics of an ideal op-amp.
  22. What happens when the common terminal of V+ and V- sources is not grounded?
  23. Define input offset voltage.
  24. Define input offset current. State the reasons for the offset currents at the
      Input of the op-amp.
  25. Define CMRR of an op-amp.
  26. What are the applications of current sources?
  27. Justify the reasons for using current sources in integrated circuits.
  28. What is the advantage of widlar current source over constant current source?
  29. Mention the advantages of Wilson current source.
  30. Define sensitivity.
  31. What are the limitations in a temperature compensated sneer-reference source?
  32. What do you mean by a band-gap referenced biasing circuit?
  33. In practical op-amps, what is the effect of high frequency on its performance?
  34. What is the need for frequency compensation in practical op-amps?
  35. Mention the frequency compensation methods.
  36. What are the merits and demerits of Dominant-pole compensation?
  37. Define slew rate.
  38. Why IC 741 is not used for high frequency applications?
39.   What causes slew rate?
40.   Draw the circuit diagram of voltage follower using IC 741.
41.   Mention some of the linear applications of op – amps :
42.   Mention some of the non – linear applications of op-amps:-
43.   What is the need for an instrumentation amplifier?
44.   List the features of instrumentation amplifier:
45.   What do you mean by a precision diode?
46.   Write down the applications of precision diode.
47.   List the applications of Log amplifiers:
48.   What are the limitations of the basic differentiator circuit?
49.   Write down the condition for good differentiation :-
50.   What is a comparator?
51.   What are the applications of comparator?
52.   What is a Schmitt trigger?
53.   What is a multivibrator?
54.   What do you mean by monostable multivibrator?
55.   What is an astable multivibrator?
56.   What is a bistable multivibrator?
57.   What are the requirements for producing sustained oscillations in feedback circuits?
58.   Mention any two audio frequency oscillators :
59.   What are the characteristics of a comparator?
60.   What is a filter?
61.   What are the demerits of passive filters?
62.   What are the advantages of active filters?
63.   Mention some commonly used active filters :
64.   List the broad classification of ADCs.
65.   List out some integrating type converters.
66.   What is integrating type converter?
67.   Explain in brief the principle of operation of successive Approximation ADC.
68.   What are the main advantages of integrating type ADCs?
69.   Where is the successive approximation type ADC’s used?
70.   What is the main drawback of a dual-slope ADC?
71.   State the advantages of dual slope ADC.
72.   Define conversion time.
73.   Define resolution of a data converter.
74.   Define accuracy of converter.
75.   What is settling time?
76.   What is meant by linearity?
77.   What is monotonic DAC?
78.   What is multiplying DAC?
79.   What is a sample and hold circuit? Where it is used?
80.   Define sample period and hold period.
Digital Circuits:

1. Convert 757.25 10 and 235610 to octal.
2. Convert 757.25 10 and 235610 to binary.
3. Convert the following binary to decimal a) (1011011.1101)2 and (b) 1011102.
4. Convert (FACE) 16 to base 8 numbers.
5. Find the decimal equivalent of (123)9.
6. Convert the following numbers with the indicated bases to decimal: (4310)5 and
7. Convert the Hexadecimal number 68BE to binary and octal.
8. Determine the base of the number for the following operations to be correct 14/2 = 5
9. Given that 1610 = 100b.Find the value of b.
10. Perform the hexadecimal addition of I) 1A6 and 4D3 and ii) 1A8 and 67B.
11. Express -67 in two’s complement form.
12. using two’s complement perform the subtraction 10011012 – 1101002.
13. using two’s complement perform the subtraction 1810 – 3310.
14. Obtain the 1’s and 2’s complements of the following binary numbers: (a) 01101011
    (b) 00000000
15. Add the decimals 67 and 54 using BCD code.
16. Convert (1029)10 to Gray code.
17. What is the need for gray code?
18. Convert 5310 to excess – 3 code and show that excess-3 code is self complementing or
      reflecting code.
19. What are the characters that can be encoded using the most common 7 – bit?
     alphanumeric code.
20. How is letter A coded in ASCII code? What bit must be complemented to change an
    ASCII letter from lower to upper case and vice versa?
21. Express 15 bit Hamming code in general.
22. Define positive and negative digital logic.
23. State two absorption properties of Boolean algebra.
24. State De-Morgan’s laws.
25. Show how bubbled AND gate works as NOR gate.
26. Why NAND and NOR gates are called as universal gates?
27. Why digital circuits are more frequently constructed with NAND and NOR gates than
     with AND and OR gates?
28. Distinguish between completely specified function and incompletely specified
29. Simplify the Boolean function F = (A + (BC)’)’
30. Minimize the expression using Boolean theorems F= x’y’ + x’yz + xz + xyz’. Draw
     The logic diagram for the minimized function.
31. If A and B are Boolean variables and if A= 1 and (A+B)’ = 0, find B.
32. Realize the function F (A, B) = A’B + AB’ using NAND gates only.
33. How many inputs and gates are required for the expression W = AB’D + ACD’ + EF
34. Name two canonical forms of Boolean algebra.
35. What is a prime implicant?
36. Express the function f(x,y,z) = x + yz as a sum of minterms.
37. For the given function write the Boolean expression in product of maxterms form
    f( a,b,c) = Σm (2,3,5,6,7).
38. Plot the expression in K-map F (w, x, y) = Σ (0, 1, 3, 5, 6) + d (2, 4)
39. Show the Karnaugh map with the encircled groups for the Boolean function,
    F = C’+ A’D’ + AB’D’.
40. List out the differences between half adder and full adder.
41. Write down the truth table of a full adder.
42. Implement half adder circuit using logic gates.
43. Implement half subtractor circuit using logic gates.
44. What will be the maximum number of outputs for a decoder with a 6 bit data word.
45. List out the differences between decoder and encoder.
46. What is a multiplexer? Give its applications.
47. What is a demultiplexer? Give its applications.
48. Mention the differences between DMUX and MUX.
49. Implement the function f = Σm (0, 1, 4, 5, 7) using 8 to 1 multiplexer.
50. Design a half subtractor using 2 to 4 decoder.
51. Write the excitation tables of JK and D flip-flops.
52. Draw the logic diagram of three – bit ring counter.
53. What is a demultiplexer?
54. Write the characteristic equation of JK and D flip-flop.
55. Convert an SR flip-flop to D flip-flop.
56. Define glitch.
57. Draw a 1 to 2 demultiplexer and 2 to1 multiplexer.
58. Draw the block diagram of SR Flip flop and give its truth table.
59. List out the limitations of SR flip-flop.
60. Convert a D flip – flop into a T flip – flop.
61. If a serial in serial out shift register has N stages and if the clock frequency is f, what
    will be the time delay between input and output?
62. Distinguish between combinational and sequential circuits.
63. Describe the behavior of SR flip-flop by means of a table.
64. How many flip-flops are required to build a counter of modulus 14 and modulus 8?
65. What is a race condition?
66. How can the race conditions be avoided in flip-flops?
67. What is a Mealy machine? Give an example.
68. Differentiate between Moore and Mealy type sequential circuits.
69. Implement a NAND gate using 4:1 Multiplexer.
70. What is a state?
71. What are state diagrams and state table?
72. What are shift register counters? List two widely used shift register counters.
73. Why is state reduction necessary?
74. Derive the characteristic equation of T flip-flop.
75. When a sequential machine is said to be trivial?
76. List out the differences between a flip-flop and a latch.
77. Why a serial counter is referred to as asynchronous.
78. Why parallel counter is faster than ripple counter?
79. Define fundamental-mode operation.
80. Define Hazard.
81. Why critical race is said to be harmful and how it is avoided in asynchronous sequential
82. What is FPGA?
83. Define Noise margin.
84. What are cycles in asynchronous sequential circuits?
85. What are races?
86. Define Fan-in and Fan out?
87. Why CMOS is preferred to TTL?
88. Compare PLA and PAL
89. What are the basic parameters to be noted before selecting an IC?
90. How does the architecture of PLA different from PROM?
91. What is the effect of increasing supply voltage on the propagation delay of the CMOS?

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