Introduction to Digital Electronics & Boolean Algebra and
Number Systems & Codes
1. Convert hexadecimal value 16 to decimal.
A. 22
C. 10
B. 16
D. 20
Answer : Option A
-------------------------------------------------------------------------------2. Convert decimal number 187 to 8-bit binary.
A. 10111011
C. 10111101
B. 11011101
D. 10111100
Answer : Option A
-------------------------------------------------------------------------------3. Convert binary 111111110010 to hexadecimal.
A. EE2
C. 2FE
B. FF2
D. FD2
Answer : Option B
-------------------------------------------------------------------------------4. Convert binary number 01011 to decimal.
A. 11
C. 15
B. 35
D. 10
Answer : Option A
-------------------------------------------------------------------------------5. Convert the binary number 1001.00102 to decimal.
A. 90.125
C. 125
B. 9.125
D. 12.5
Answer : Option B
-------------------------------------------------------------------------------6. The voltages in digital electronics are continuously variable.
A. True
B. False
Answer : Option B
-------------------------------------------------------------------------------7. One hex digit is sometimes referred to as a(n):
A. byte
C. grouping
B. nibble
D. instruction
Answer: Option B
-------------------------------------------------------------------------------8. Convert 59.7210 to BCD.
A. 111011
C. 1110.11
B. 01011001.01110010
D. 0101100101110010
Answer: Option B
-------------------------------------------------------------------------------9. Convert 8B3F Hexadecimal to binary.
A. 35647
C. 1011001111100011
B. 011010
D. 1000101100111111
Answer: Option D
-------------------------------------------------------------------------------10. Which is typically the longest: bit, byte, nibble, word?
A. Bit
C. Nibble
B. Byte
D. Word
Answer: Option D
-------------------------------------------------------------------------------11. Convert decimal 64 to binary.
A. 01010010
C. 00110110
Answer: Option B
B. 01000000
D. 01001000
-------------------------------------------------------------------------------12. Convert hexadecimal value C1 to binary.
A. 11000001
C. 111000100
B. 1000111
D. 111000001
Answer: Option A
-------------------------------------------------------------------------------13. Convert 178 octal number to decimal.
A. 51
C. 57
B. 82
D. 15
Answer: Option D
-------------------------------------------------------------------------------14. Convert 010111100 binary number to octal.
A. 172
C. 174
B. 272
D. 274
Answer: Option D
-------------------------------------------------------------------------------15. How many binary digits are required to count to 10010?
A. 7
C. 3
B. 2
D. 100
Answer: Option A
-------------------------------------------------------------------------------16. The BCD number for decimal 347 is ________.
A. 1100 1011 1000
B. 0011 0100 0111
C. 0011 0100 0001
D. 1100 1011 0110
Answer: Option B
-------------------------------------------------------------------------------17. The binary number for octal 458 is ________.
A. 100010
C. 110101
B. 100101
D. 100100
Answer: Option B
-------------------------------------------------------------------------------18. The sum of 11101 + 10111 equals ________.
A. 110011
C. 110100
B. 100001
D. 100100
Answer: Option C
-------------------------------------------------------------------------------19. Convert 10011010 binary number to decimal.
A. 154
C. 153
B. 155
D. 157
Answer: Option A
-------------------------------------------------------------------------------20. The decimal number 188 is equal to the binary number ________.
A. 10111100
C. 1100011
B. 0111000
D. 1111000
Answer: Option A
-------------------------------------------------------------------------------21. Convert 001101011 binary number to octal.
A. 153
C. 253
B. 351
D. 352
Answer: Option A
-------------------------------------------------------------------------------22. A binary number's value changes most drastically when the ________ is changed.
A. MSB
B. frequency
C. LSB
D. duty cycle
Answer: Option A
-------------------------------------------------------------------------------23. Convert decimal 213 to binary.
A. 11001101
C. 11011111
B. 11010101
D. 10010111
Answer: Option B
24. The decimal number for octal 748 is ________.
A. 74
C. 22
B. 60
D. 62
Answer: Option B
-------------------------------------------------------------------------------25. The sum of the two BCD numbers, 0011 + 0011, is ________.
A. 0110
C. 0011
B. 0111
D. 1100
Answer: Option A
-------------------------------------------------------------------------------26. Convert binary 01001110 to decimal.
A. 4E
C. 76
B. 78
D. 116
Answer: Option B
-------------------------------------------------------------------------------27. Which is not a word size?
A. 64
C. 16
B. 28
D. 8
Answer: Option B
-------------------------------------------------------------------------------27. The octal numbering system:
A. simplifies tasks
B. groups binary numbers in groups of 4
C. saves time
D. simplifies tasks and saves time
Answer : Option D
-------------------------------------------------------------------------------28. The binary number 1110 is equal to the decimal number ________.
A. 3
C. 7
B. 1
D. 14
Answer: Option D
-------------------------------------------------------------------------------29. Convert 768 octal number to binary.
A. 1101112
C. 1111002
B. 1111102
D. 1001112
Answer: Option B
-------------------------------------------------------------------------------30. Convert 1100101000110101 to hexadecimal.
A. 121035
C. 53AC1
B. CA35
D. 530121
Answer: Option B
-------------------------------------------------------------------------------31. Convert 281 decimal number to octal.
A. 134
C. 331
B. 431
D. 133
Answer: Option B
-------------------------------------------------------------------------------32. When using even parity, where is the parity bit placed?
A. Before the MSB
B. After the LSB
C. In the parity word
D. After the odd parity bit
Answer: Option A
-------------------------------------------------------------------------------33. Convert 35 octal number to decimal.
A. 71
C. 92
B. 17
D. 29
Answer: Option D
-------------------------------------------------------------------------------34. Convert binary 11001111 to hexadecimal.
A. 8F
C. DF
B. CE
D. CF
Answer: Option D
-------------------------------------------------------------------------------35. Convert 1731 to decimal.
A. 216.4
C. 3D9
B. 985
D. 1123
Answer: Option B
-------------------------------------------------------------------------------36. An analog signal has a range from 0 V to 5 V. What is the total number of analog
possibilities within this range?
A. 5
C. 250
B. 50
D. infinite
Answer: Option D
37. Hexadecimal letters A through F are used for decimal equivalent values from:
A. 1 through 6
B. 9 through 14
C. 10 through 15
D. 11 through 17
Answer: Option C
--------------------------------------------------------------------------------
38. Convert 35 decimal number to 8-bit binary.
A. 000100102
C. 001000112
B. 000100112
D. 001000102
Answer: Option C
-------------------------------------------------------------------------------39. Convert C9 hexadecimal number to binary.
A. 10111001
C. 10011100
B. 10111011
D. 11001001
Answer: Option D
-------------------------------------------------------------------------------40. Convert 125 decimal number to hexadecimal.
A. 7D
C. 7C
B. D7
D. C7
Answer: Option A
-------------------------------------------------------------------------------41. A decimal 11 in BCD is ________.
A. 00001011
C. 00010001
B. 00001100
D. 00010010
Answer: Option C
-------------------------------------------------------------------------------42. What is the resultant binary of the decimal problem 49 + 01 = ?
A. 01010101
C. 00110010
Answer: Option C
B. 00110101
D. 00110001
-------------------------------------------------------------------------------43. The difference of 111 – 001 equals ________.
A. 100
C. 001
B. 111
D. 110
Answer: Option D
44. Convert the binary number 1100 to Gray code.
A. 0011
C. 1100
B. 1010
D. 1001
Answer: Option B
-------------------------------------------------------------------------------45. The binary number 11101011000111010 can be written in hexadecimal as ________.
A. DD63A
C. 1D33A
B. 1D63A
D. 1D631
Answer: Option B
-------------------------------------------------------------------------------46. Which of the following is an invalid BCD code?
A. 0011
C. 0101
B. 1101
D. 1001
Answer: Option B
-------------------------------------------------------------------------------47. What decimal number does 25 represent?
A. 10
C. 25
B. 31
D. 32
Answer: Option D
-------------------------------------------------------------------------------48. Convert the Gray code 1011 to binary.
A. 1011
C. 0100
B. 1010
D. 1101
Answer: Option D
-------------------------------------------------------------------------------49. Determine the decimal equivalent of the signed binary number 11110100 in 1's
complement.
A. 116
C. –11
B. –12
D. 128
Answer: Option C
-------------------------------------------------------------------------------50. What is the difference between binary coding and binary-coded decimal?
A. BCD is pure binary.
B. Binary coding has a decimal format.
C. BCD has no decimal format.
D. Binary coding is pure binary.
Answer: Option D
-------------------------------------------------------------------------------51. Convert 127 decimal number to BCD.
A. 011100100001
C. 001010111
B. 111010001
D. 000100100111
Answer: Option D
-------------------------------------------------------------------------------52. Digital electronics is based on the ________ numbering system.
A. decimal
C. binary
B. octal
D. hexadecimal
Answer: Option C
-------------------------------------------------------------------------------53. An informational signal that makes use of binary digits is considered to be:
A. solid state
B. digital
C. analog
D. non-oscillating
Answer: Option B
-------------------------------------------------------------------------------54. The 1's complement of 10011101 is ________.
A. 01100010
C. 01100001
B. 10011110
D. 01100011
Answer: Option A
-------------------------------------------------------------------------------55. The binary number 101110101111010 can be written in octal as ________.
A. 51562
C. 65627
B. 56577
D. 56572
Answer: Option D
-------------------------------------------------------------------------------56. Convert 457 decimal to hexadecimal.
A. 711
C. 811
B. 2C7
D. 1C9
Answer: Option D
-------------------------------------------------------------------------------57. Convert the decimal number 151.75 to binary.
A. 10000111.11
C. 00111100.00
B. 11010011.01
D. 10010111.11
Answer: Option D
58. Convert 1048 octal number to binary.
A. 0010001002
C. 00101002
B. 1000000012
D. 10000012
Answer: Option A
-------------------------------------------------------------------------------59. 3 × 011 + 7 × 100 is equal to ________.
A. 3.7
B. 37
C. 10
D. 370
Answer: Option B
-------------------------------------------------------------------------------60. 3428 is the decimal value for which of the following binary-coded decimal (BCD)
groupings?
A. 11010001001000
C. 011010010000010
B. 11010000101000
D. 110100001101010
Answer: Option B
-------------------------------------------------------------------------------61. The binary-coded decimal (BCD) system can be used to represent each of the 10
decimal digits as a(n):
A. 4-bit binary code
B. 8-bit binary code
C. 16-bit binary code
D. ASCII code
Answer: Option A
-------------------------------------------------------------------------------62. The decimal number 18 is equal to the binary number ________.
A. 11110
C. 10010
B. 10001
D. 1111000
Answer: Option C
-------------------------------------------------------------------------------63. The 2's complement of 11100111 is ________.
A. 11100110
C. 00011000
B. 00011001
D. 00011010
Answer: Option B
-------------------------------------------------------------------------------64. Convert 469 decimal number to BCD.
A. 100101101000
C. 100001101001
B. 010001101001
D. 100101100100
Answer: Option B
65. Express the decimal number –37 as an 8-bit number in sign-magnitude.
A. 10100101
C. 11011000
B. 00100101
D. 11010001
Answer: Option A
-------------------------------------------------------------------------------66. Convert the following BCD number to decimal.
010101101001
A. 539
C. 569
B. 2551
D. 1552
Answer: Option C
-------------------------------------------------------------------------------67. The binary number 11001110 is equal to the decimal number ________.
A. 12
C. 127
B. 206
D. 66
Answer: Option B
-------------------------------------------------------------------------------68. The Hexadecimal number for F3A is ________.
A. 111100111010
C. 000000111010
B. 111100111110
D. 000011000100
Answer: Option A
-------------------------------------------------------------------------------69. Convert the following BCD number to decimal.
100000000011bcd
A. 8003
C. 1003
Answer: Option B
B. 803
D. 103
-------------------------------------------------------------------------------70. Convert 14B hexadecimal number to binary.
A. 1011010000012
C. 0001010011012
B. 0001010010112
D. 1101010000012
Answer: Option B
-------------------------------------------------------------------------------71. What is the result when a decimal 5238 is converted to base 16?
A. 327.375
C. 1388
B. 12.166
D. 1476
Answer: Option D
72. The octal number for binary 1101110101110110 is ________.
A. 6545218
C. 1566568
B. 5565618
D. 1565668
Answer: Option D
-------------------------------------------------------------------------------73. Convert 1CF hexadecimal number to decimal.
A. 463
C. 479
B. 4033
D. 4049
Answer: Option A
-------------------------------------------------------------------------------74. Convert the binary number 1011010 to hexadecimal.
A. 5B
C. 5A
B. 5F
D. 5C
Answer: Option C
-------------------------------------------------------------------------------75. Convert 74 decimal number to hexadecimal.
A. A416
C. 4A16
B. B416
D. 4B16
Answer: Option C
-------------------------------------------------------------------------------76. Convert hexadecimal C0B to binary.
A. 110000001011
C. 110000001100
B. 110000001001
D. 110100001011
Answer: Option A
-------------------------------------------------------------------------------77. Convert binary 1001 to hexadecimal.
A. 9
C. 101
B. 11
D. 10
Answer: Option A
-------------------------------------------------------------------------------78. Convert 731 Hexadecimal to decimal.
A. 216.4
C. 3D9
B. 985
D. 1841
Answer: Option D
79. What is the decimal value of the hexadecimal number 777?
A. 191
C. 19
B. 1911
D. 19111
Answer: Option B
-------------------------------------------------------------------------------80. Convert 11001001 (binary) to decimal.
A. 201
C. 20
B. 2001
D. 210
Answer: Option A
-------------------------------------------------------------------------------81. Convert 39 decimal number to octal.
A. 638
C. 478
B. 368
D. 748
Answer: Option C
-------------------------------------------------------------------------------82. Convert B5 hexadecimal number to decimal.
A. 212
C. 165
B. 197
D. 181
Answer: Option D
-------------------------------------------------------------------------------83. The BCD number for decimal 16 is ________.
A. 00010110
C. 00010010
B. 00010000
D. 11100000
Answer: Option A
-------------------------------------------------------------------------------84. Convert 527 Hexadecimal to binary.
A. 343
C. 010100100111
B. 001101000111
D. 011100100101
Answer: Option C
-------------------------------------------------------------------------------85. Convert 527 Octal to binary.
A. 011100111
C. 343
B. 101010111
D. 111010101
Answer: Option B
-------------------------------------------------------------------------------86. The base of the hexadecimal system is:
A. eight.
C. ten.
B. sixteen.
D. two.
Answer: Option B
-------------------------------------------------------------------------------87. Which of the following is the primary advantage of using the BCD code instead of
straight binary coding?
A. Fewer bits are required to represent a decimal number with the BCD code.
B. The relative ease of converting to and from decimal.
C. BCD codes are easily converted to hexadecimal codes.
D. BCD codes are easily converted to straight binary codes.
Answer: Option B
-------------------------------------------------------------------------------88. How many BCD code bits and how many straight binary bits would be required to
represent the decimal number 643?
A. 12 BCD, 12 binary
B. 12 BCD, 10 binary
C. 12 BCD, 9 binary
D. 16 BCD, 9 binary
Answer: Option B
89. When using the repeated division by 2 method of converting from decimal to binary,
one must write the first remainder as the:
A. MSB
B. MSB, provided the following sequence of remainders are written in descending order
until the final remainder is achieved.
C. LSB
D. LSB, provided the final remainder is used to replace the original LSB, which is then
moved to the MSB position.
Answer: Option A
90. Any number with an exponent of zero is equal to:
A. zero
B. one
C. that number
D. ten
Answer : Option B
-------------------------------------------------------------------------------91. In the decimal numbering system, what is the MSD?
A. The middle digit of a stream of numbers
B. The digit to the right of the decimal point
C. The last digit on the right
D. The digit with the most weight
Answer: Option D
-------------------------------------------------------------------------------92. Which of the following statements does NOT describe an advantage of digital
technology?
A. The values may vary over a continuous range.
B. The circuits are less affected by noise.
C. The operation can be programmed.
D. Information storage is easy.
Answer: Option A
-------------------------------------------------------------------------------93. The range of voltages between VL(max) and VH(min) are ________.
A. unknown
B. unnecessary
C. unacceptable
D. between 2 V and 5 V
Answer: Option C
-------------------------------------------------------------------------------94. What are the symbols used to represent digits in the binary number system?
A. 0,1
B. 0,1,2
C. 0 through 8
D. 1,2
Answer: Option A
-------------------------------------------------------------------------------95. NAND gate produces output HIGH, when
A. all the time
B. when any input is LOW
C. when any input is HIGH
D. when all inputs are HIGH
Answer: Option B
-------------------------------------------------------------------------------96. Give the decimal value of binary 10010.
A. 610
C. 1810
B. 910
D. 2010
Answer: Option C
-------------------------------------------------------------------------------97. The output of a NOT gate is HIGH when ________.
A. the input is LOW
B. the input is HIGH
C. the input changes from LOW to HIGH
D. voltage is removed from the gate
Answer: Option A
-------------------------------------------------------------------------------98. The output of an OR gate is LOW when ________.
A. all inputs are LOW
B. any input is LOW
C. any input is HIGH
D. all inputs are HIGH
Answer: Option A
-------------------------------------------------------------------------------99. In a certain digital waveform, the period is four times the pulse width. The duty cycle
is ________.
A. 0%
C. 50%
Answer: Option B
B. 25%
D. 100%
100. In positive logic, ________.
A. a HIGH = 1, a LOW = 0
B. a LOW = 1, a HIGH = 0
C. only HIGHs are present
D. only LOWs are present
Answer: Option A
-------------------------------------------------------------------------------101. Convert the fractional binary number 0000.1010 to decimal.
A. 0.625
C. 0.55
B. 0.50
D. 0.10
Answer: Option A
-------------------------------------------------------------------------------102. Digital representations of numerical values of quantities may BEST be described as
having characteristics:
A. that are difficult to interpret because they are continuously changing.
B. that vary constantly over a continuous range of values.
C. that vary in constant and direct proportion to the values they represent.
D. that vary in discrete steps in proportion to the values they represent.
Answer: Option D
-------------------------------------------------------------------------------103. A common instrument used in troubleshooting a digital circuit is a(n) ________.
A. logic probe
B. oscilloscope
C. pulser
D. all of the above
Answer: Option D
-------------------------------------------------------------------------------104. Convert the fractional decimal number 6.75 to binary.
A. 0111.1100 B. 0110.1010
C. 0110.1100 D. 0110.0110
Answer: Option C
-------------------------------------------------------------------------------105. A pulse has a period of 15 ms. Its frequency is ________.
A. 6.66 Hz
B. 66.66 Hz
C. 666.66 Hz
D. 15 Hz
Answer: Option B
-------------------------------------------------------------------------------106. Give the decimal value of binary 10000110.
A. 13410 B. 14410
C. 11010 D. 12610
Answer: Option A
107. The rise time is the time it takes a pulse to go from ________.
A. the base line to the maximum HIGH voltage
B. 10% of the pulse amplitude to the maximum HIGH voltage
C. the base line to 90% of the pulse amplitude
D. 10% of the pulse amplitude to 90% of the pulse amplitude
Answer: Option D
-------------------------------------------------------------------------------108. What is the decimal value of 23 ?
A. 2
C. 6
B. 4
D. 8
Answer: Option D
-------------------------------------------------------------------------------109. What is the typical invalid voltage for a binary signal?
A. 0.7–2.8 volts
B. 0.8–3 volts
C. 0.8–2 volts
D. 0.7–2.5 volts
Answer: Option C
-------------------------------------------------------------------------------110. Convert the fractional binary number 0001.0010 to decimal.
A. 1.40
C. 1.20
B. 1.125
D. 1.80
Answer: Option B
-------------------------------------------------------------------------------112. Convert the fractional binary number 10010.0100 to decimal.
A. 24.50
C. 18.40
B. 18.25
D. 16.25
Answer: Option B
113. How many binary bits are necessary to represent 748 different numbers?
A. 9
C. 10
B. 7
D. 8
Answer: Option C
-------------------------------------------------------------------------------114. Any number with an exponent of one is equal to:
A. zero.
B. one.
C. two.
D. that number.
Answer: Option D
-------------------------------------------------------------------------------115. What is the decimal value of 2–1 ?
A. 0.5
C. 0.05
B. 0.25
Answer: Option A
D. 0.1
-------------------------------------------------------------------------------116. The frequency of a pulse train is 2 kHz. The pulse period is ________.
A. 5 ms
B. 50 ms
C. 500 s
D. 2 s
Answer: Option C
-------------------------------------------------------------------------------117. What has happened to the advances in digital technologies over the past three
decades?
A. Slowed down considerably
B. Continued to increase, but at a decreasing rate
C. Made excellent progress
D. Nothing short of phenomenal
Answer: Option D
-------------------------------------------------------------------------------118. How many unique symbols are used in the decimal number system?
A. One
C. Ten
B. Nine
D. Unlimited
Answer: Option C
119. Convert the following SOP expression to an equivalent POS expression.
A.
B.
C.
D.
Answer: Option C
-------------------------------------------------------------------------------120. Determine the values of A, B, C, and D that make the sum term
to zero.
A.A = 1, B = 0, C = 0, D = 0
B. A = 1, B = 0, C = 1, D = 0
C. A = 0, B = 1, C = 0, D = 0
D.A = 1, B = 0, C = 1, D = 1
Answer: Option B
-------------------------------------------------------------------------------121. Which of the following expressions is in the sum-of-products (SOP) form?
A.(A + B)(C + D)
B. (A)B(CD)
C. AB(CD)
D.AB + CD
Answer: Option D
-------------------------------------------------------------------------------122. Derive the Boolean expression for the logic circuit shown below:
A.
B.
C.
D.
equal
Answer: Option A
-------------------------------------------------------------------------------123. From the truth table below, determine the standard SOP expression.
A.
B.
C.
D.
Answer: Option D
-------------------------------------------------------------------------------124. One of De Morgan's theorems states that
. Simply stated, this means that
logically there is no difference between:
A.a NOR and an AND gate with inverted inputs
B. a NAND and an OR gate with inverted inputs
C. an AND and a NOR gate with inverted inputs
D.a NOR and a NAND gate with inverted inputs
Answer: Option B
125. The commutative law of Boolean addition states that A + B = A × B.
A.True
B.False
Answer: Option B
-------------------------------------------------------------------------------126. Applying DeMorgan's theorem to the expression
, we get ________.
A.
B.
C.
D.
Answer: Option A
127. The systematic reduction of logic circuits is accomplished by:
A.using Boolean algebra
B. symbolic reduction
C. TTL logic
D.using a truth table
Answer: Option A
-------------------------------------------------------------------------------128. Which output expression might indicate a product-of-sums circuit construction?
A.
B.
C.
D.
Answer: Option C
--------------------------------------------------------------------------------
129. An AND gate with schematic "bubbles" on its inputs performs the same function as
a(n)________ gate.
A.NOT
B. OR
C. NOR
D.NAND
Answer: Option C
-------------------------------------------------------------------------------130. For the SOP expression
output column?
A.1
C. 3
, how many 1s are in the truth table's
B. 2
D.5
Answer: Option C
-------------------------------------------------------------------------------132. A truth table for the SOP expression
has how many input
combinations?
A.1
B. 2
C. 4
D.8
Answer: Option D
-------------------------------------------------------------------------------133. How many gates would be required to implement the following Boolean expression
before simplification? XY + X(X + Z) + Y(X + Z)
A.1
B. 2
C. 4
D.5
Answer: Option D
-------------------------------------------------------------------------------134. Determine the values of A, B, C, and D that make the product term
equal to
1.
A.A = 0, B = 1, C = 0, D = 1
B. A = 0, B = 0, C = 0, D = 1
C. A = 1, B = 1, C = 1, D = 1
D.A = 0, B = 0, C = 1, D = 0
Answer: Option A
-------------------------------------------------------------------------------135. What is the primary motivation for using Boolean algebra to simplify logic
expressions?
A.It may make it easier to understand the overall function of the circuit.
B. It may reduce the number of gates.
C. It may reduce the number of inputs required.
D.all of the above
Answer: Option B
-------------------------------------------------------------------------------136. How many gates would be required to implement the following Boolean expression
after simplification? XY + X(X + Z) + Y(X + Z)
A.1
B. 2
C. 4
D.5
Answer: Option C
-------------------------------------------------------------------------------137. AC + ABC = AC
A.True
B.False
Answer: Option A
-------------------------------------------------------------------------------138. When
are the inputs to a NAND gate, according to De Morgan's theorem, the
output expression could be:
A.X = A + B
B.
C. X = (A)(B)
D.
Answer: Option A
-------------------------------------------------------------------------------139. Which Boolean algebra property allows us to group operands in an expression in
any order without affecting the results of the operation [for example, A + B = B +
A]?
A.associative
B. commutative
C. Boolean
D.distributive
Answer: Option B
-------------------------------------------------------------------------------140.
Applying DeMorgan's theorem to the expression
, we get ________
A.
B.
C.
D.
Answer: Option A
-------------------------------------------------------------------------------141. When grouping cells within a K-map, the cells must be combined in groups of
________.
A.2s
B. 1, 2, 4, 8, etc.
C. 4s
D.3s
Answer: Option B
-------------------------------------------------------------------------------142. Use Boolean algebra to find the most simplified SOP expression for F = ABD + CD
+ ACD + ABC + ABCD.
A.F = ABD + ABC + CD
B. F = CD + AD
C. F = BC + AB
D.F = AC + AD
Answer: Option A
-------------------------------------------------------------------------------143. Occasionally, a particular logic expression will be of no consequence in the
operation of a circuit, such as a BCD-to-decimal converter. These result in
________terms in the K-map and can be treated as either ________ or ________, in
order to ________ the resulting term.
A.don't care, 1s, 0s, simplify
B. spurious, ANDs, ORs, eliminate
C. duplicate, 1s, 0s, verify
D.spurious, 1s, 0s, simplify
Answer: Option A
-------------------------------------------------------------------------------144. The NAND or NOR gates are referred to as "universal" gates because either:
A.can be found in almost all digital circuits
B. can be used to build all the other types of gates
C. are used in all countries of the world
D.were the first gates to be integrated
Answer: Option B
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Logic Families
1. What is unique about TTL devices such as the 74SXX?
A. These devices use Schottky transistors and diodes to prevent them from going into
saturation; this results in faster turn-on and turn-off times, which translates into higher
frequency operation.
B. The gate transistors are silicon (S), and the gates therefore have lower values of
leakage current.
C. The S denotes the fact that a single gate is present in the IC rather than the usual
package of 2–6 gates.
D. The S denotes a slow version of the device, which is a consequence of its higher
power rating.
Answer: Option A
-------------------------------------------------------------------------------2. Which of the following logic families has the shortest propagation delay?
A. CMOS B. BiCMOS
C. ECL D. 74SXX
Answer: Option C
-------------------------------------------------------------------------------3. Why must CMOS devices be handled with care?
A. so they don’t get dirty
B. because they break easily
C. because they can be damaged by static electricity discharge
Answer: Option C
-------------------------------------------------------------------------------4. Special handling precautions should be taken when working with MOS devices.
Which of the following statements is not one of these precautions?
A. All test equipment should be grounded.
B. MOS devices should have their leads shorted together for shipment and storage.
C. Never remove or insert MOS devices with the power on.
D. Workers handling MOS devices should not have grounding straps attached to their
wrists.
Answer: Option D
-------------------------------------------------------------------------------5. What should be done to unused inputs on TTL gates?
A. They should be left disconnected so as not to produce a load on any of the other
circuits and to minimize power loading on the voltage source.
B. All unused gates should be connected together and tied to V through a 1 k resistor.
C. All unused inputs should be connected to an unused output; this will ensure
compatible loading on both the unused inputs and unused outputs.
D. Unused AND and NAND inputs should be tied to VCC through a 1 k resistor; unused
OR and NOR inputs should be grounded.
Answer: Option D
-------------------------------------------------------------------------------6. Assume that a particular IC has a supply voltage (Vcc) equal to +5 V and ICCH = 10
mA and ICCL = 23 mA. What is the power dissipation for the chip?
A. 50 mW
B. 82.5 mW
C. 115 mW
D. 165 mW
Answer: Option B
-------------------------------------------------------------------------------7. Can a 74HCMOS logic gate directly connect to a 74ALSTTL gate?
A. Yes B. No
Answer: Option A
-------------------------------------------------------------------------------8. What is the major advantage of ECL logic?
A. very high speed
B. wide range of operating voltage
C. very low cost
D. very high power
Answer: Option A
-------------------------------------------------------------------------------9. As a general rule, the lower the value of the speed–power product, the better the
device because of its:
A. long propagation delay and high power consumption
B. long propagation delay and low power consumption
Answer: Option B
-------------------------------------------------------------------------------10. What is the range of invalid TTL output voltage?
A. 0.0–0.4 V
B. 0.4–2.4 V
C. 2.4–5.0 V
D. 0.0–5.0 V
Answer: Option B
11. What is the difference between the 54XX and 74XX series of TTL logic gates?
A. 54XX is faster.
B. 54XX is slower.
C. 54XX has a wider power supply and expanded temperature range.
D. 54XX has a narrower power supply and contracted temperature range.
Answer: Option C
-------------------------------------------------------------------------------12. An open collector output can ________ current, but it cannot ________.
A. sink, source current
B. source, sink current
C. sink, source voltage
D. source, sink voltage
Answer: Option A
-------------------------------------------------------------------------------13. Why is a decoupling capacitor needed for TTL ICs and where should it be
connected?
A. to block dc, connect to input pins
B. to reduce noise, connect to input pins
C. to reduce the effects of noise, connect between power supply and ground
Answer: Option C
-------------------------------------------------------------------------------14. Using the schematic diagram of a TTL NAND gate, determine the state of each
transistor (ON or OFF) when all inputs are high.
A. Q1-ON, Q2-OFF, Q3-ON, Q4-OFF
B. Q1-ON, Q2-ON, Q3-OFF, Q4-OFF
C. Q1-OFF, Q2-OFF, Q3-ON, Q4-ON
D. Q1-OFF, Q2-ON, Q3-OFF, Q4-ON
Answer: Option D
-------------------------------------------------------------------------------15. If all inputs to a TTL NAND gate are low, what is the ON, OFF condition of each
transistor in the circuit?
A. Q1-ON, Q2-OFF, Q3-ON, Q4-OFF
B. Q1-ON, Q2-ON, Q3-OFF, Q4-OFF
C. Q1-OFF, Q2-OFF, Q3-ON, Q4-ON
D. Q1-OFF, Q2-ON, Q3-OFF, Q4-ON
Answer: Option A
16. Which of the following summarizes the important features of emitter-coupled logic
(ECL)?
A. low noise margin, low output voltage swing, negative voltage operation, fast, and high
power consumption
B. good noise immunity, negative logic, high-frequency capability, low power
dissipation, and short propagation time
C. low propagation time, high-frequency response, low power consumption, and high
output voltage swings
D. poor noise immunity, positive supply voltage operation, good low-frequency
operation, and low power
Answer: Option A
-------------------------------------------------------------------------------17. Why is a pull-up resistor needed for an open collector gate?
A. to provide Vcc for the IC
B. to provide ground for the IC
C. to provide the HIGH voltage
D. to provide the LOW voltage
Answer: Option C
-------------------------------------------------------------------------------18. Why is a pull-up resistor needed when connecting TTL logic to CMOS logic?
A. to increase the output LOW voltage
B. to decrease the output LOW voltage
C. to increase the output HIGH voltage
D. to decrease the output HIGH voltage
Answer: Option C
-------------------------------------------------------------------------------19. The word "interfacing" as applied to digital electronics usually means:
A. a conditioning circuit connected between a standard TTL NAND gate and a standard
TTL OR gate
B. a circuit connected between the driver and load to condition a signal so that it is
compatible with the load
C. any gate that is a TTL operational amplifier designed to condition signals between
NMOS transistors
D. any TTL circuit that is an input buffer stage
Answer: Option B
-------------------------------------------------------------------------------20. The rise time (tr) is the time it takes for a pulse to rise from its ________ point up to
its ________ point. The fall time (tf) is the length of time it takes to fall from the
________ to the ________ point.
A. 10%, 90%, 90%, 10%
B. 90%, 10%, 10%, 90%
C. 20%, 80%, 80%, 20%
D. 10%, 70.7%, 70.7%, 10%
Answer: Option A
21. The term buffer/driver signifies the ability to provide low output currents to drive
light loads.
A. True B. False
Answer: Option B
-------------------------------------------------------------------------------22. PMOS and NMOS ________.
A. represent MOSFET devices utilizing either P-channel or N-channel devices
exclusively within a given gate
B. are enhancement-type CMOS devices used to produce a series of high-speed logic
known as 74HC
C. represent positive and negative MOS-type devices, which can be operated from
differential power supplies and are compatible with operational amplifiers
D. None of the above
Answer: Option A
-------------------------------------------------------------------------------23. Why is the operating frequency for CMOS devices critical for determining power
dissipation?
A. At low frequencies, power dissipation increases.
B. At high frequencies, the gate will only be able to deliver 70.7 % of rated power.
C. At high frequencies, charging and discharging the gate capacitance will draw a heavy
current from the power supply and thus increase power dissipation.
D. At high frequencies, the gate will only be able to deliver 70.7 % of rated power and
charging and discharging the gate capacitance will draw a heavy current from the power
supply and thus increase power dissipation.
Answer: Option C
-------------------------------------------------------------------------------24. Ten TTL loads per TTL driver is known as:
A. noise immunity
B. fan-out
C. power dissipation
D. propagation delay
Answer: Option B
-------------------------------------------------------------------------------25. The problem of different current requirements when CMOS logic circuits are driving
TTL logic circuits can usually be overcome by the addition of:
A. a CMOS inverting bilateral switch between the stages
B. a TTL tristate inverting buffer between the stages
C. a CMOS noninverting bilateral switch between the stages
D. a CMOS buffer or inverting buffer
Answer: Option D
26. Totem-pole outputs ________ be connected ________ because ________.
A. can, in parallel, sometimes higher current is required
B. cannot, together, if the outputs are in opposite states excessively high currents can
damage one or both devices
C. should, in series, certain applications may require higher output voltage
D. can, together, together they can handle larger load currents and higher output voltages
Answer: Option B
-------------------------------------------------------------------------------27. The high input impedance of MOSFETs:
A. allows faster switching
B. reduces input current and power dissipation
C. prevents dense packing
D. creates low-noise reactions
Answer: Option B
-------------------------------------------------------------------------------28. The output current capability of a single 7400 NAND gate when HIGH is called
________.
A. source current
B. sink current
C. IOH
D. source current of IOH
Answer: Option A
-------------------------------------------------------------------------------29. The time needed for an output to change from the result of an input change is known
as:
A. noise immunity
B. fan-out
C. propagation delay
D. rise time
Answer: Option C
--------------------------------------------------------------------------------
30. The problem of interfacing IC logic families that have different supply voltages
(VCC's) can be solved by using a:
A. level-shifter
B. tristate shifter
C. decoupling capacitor
D. pull-down resistor
Answer: Option A
-------------------------------------------------------------------------------31. What is the advantage of using low-power Schottky (LS) over standard TTL logic?
A. more power dissipation
B. less power dissipation
C. cost is less
D. cost is more
Answer: Option B
-------------------------------------------------------------------------------32. When is a level-shifter circuit needed in interfacing logic?
A. A level shifter is always needed.
B. A level shifter is never needed.
C. when the supply voltages are the same
D. when the supply voltages are different
Answer: Option D
-------------------------------------------------------------------------------33. A TTL totem-pole circuit is designed so that the output transistors:
A. are always on together
B. provide linear phase splitting
C. provide voltage regulation
D. are never on together
Answer: Option D
-------------------------------------------------------------------------------34. The most common TTL series ICs are:
A. E-MOSFET B. 7400
C. quad D. AC00
Answer: Option B
-------------------------------------------------------------------------------35. Fan-out is determined by taking the ________ result(s) of ________.
A. smaller,
B. larger,
C. smaller,
D. average,
Answer: Option C
-------------------------------------------------------------------------------36. Which family of devices has the characteristic of preventing saturation during
operation?
A. TTL B. MOS
C. ECL D. IIL
Answer: Option C
-------------------------------------------------------------------------------37. How many 74LSTTL logic gates can be driven from a 74TTL gate?
A. 10
C. 200
B. 20
D. 400
Answer: Option B
-------------------------------------------------------------------------------38. What is the difference between the 74HC00 series and the 74HCT00 series of CMOS
logic?
A. The HCT series is faster.
B. The HCT series is slower.
C. The HCT series is input and output voltage compatible with TTL.
D. The HCT series is not input and output voltage compatible with TTL.
Answer: Option C
-------------------------------------------------------------------------------39. From the following specifications determine the fan-out for the logic family.
A. HIGH state is 16, LOW state is 8
B. HIGH state is 8, LOW state is 16
C. HIGH state is 4, LOW state is 8
D. HIGH state is 8, LOW state is 4
Answer: Option B
-------------------------------------------------------------------------------40. Why are the maximum value of VOL and the minimum value of VOH used to
determine the noise margin rather than the typical values for these parameters?
A. These are worst-case conditions.
B. These are normal conditions.
C. These are best-case conditions.
D. It doesn't matter what values are used.
Answer: Option A
-------------------------------------------------------------------------------41. What is the standard TTL noise margin?
A. 5.0 V
B. 0.0 V
C. 0.8 V
D. 0.4 V
Answer: Option D
-------------------------------------------------------------------------------42. How can ECL have both a NOR and an OR output?
A. ECL does not have this feature.
B. They are simply the inverse of each other.
Answer: Option B
-------------------------------------------------------------------------------43. Which logic family is characterized by a multiemitter transistor on the input?
A. ECL
B. CMOS
C. TTL
D. None of the above
Answer: Option C
-------------------------------------------------------------------------------44. How is the speed–power product of a logic family determined?
A. The propagation delay in s is multiplied by the power dissipation in mW.
B. The propagation delay in ms is multiplied by the power dissipation in W.
C. The propagation delay in ns is multiplied by the power dissipation in mW.
D. The propagation delay in ns is multiplied by the power dissipation in W.
Answer: Option C
-------------------------------------------------------------------------------45. The problem of the VOH(min) of a TTL IC being too low to drive a CMOS circuit
and meet the CMOS requirement of VIH(min) is usually easily overcome by:
A. adding a fixed voltage-divider bias resistive network at the output of the TTL device
B. avoiding this condition and only using TTL to drive TTL
C. adding an external pull-down resistor to ground
D. adding an external pull-up resistor to VCC
Answer: Option D
-------------------------------------------------------------------------------46. How does the 4000 series of CMOS logic compare in terms of speed and power
dissipation to the standard family of TTL logic?
A. more power dissipation and slower speed
B. more power dissipation and faster speed
C. less power dissipation and faster speed
D. less power dissipation and slower speed
Answer: Option D
-------------------------------------------------------------------------------47. What should be done with unused inputs to a TTL NAND gate?
A. let them float
B. tie them LOW
C. tie them HIGH
Answer: Option C
-------------------------------------------------------------------------------48. The TTL HIGH level source current is higher than the LOW level sinking current.
A. True B. False
Answer: Option A
49. A type of digital circuit technology that uses bipolar junction transistors is ________.
A. TTL B. CMOS
C. LSI D. NMOS
Answer: Option A
-------------------------------------------------------------------------------50. A classification of ICs with complexities of 12 to 100 equivalent gates on a chip is
known as ________.
A. SSI
C. LSI
B. MSI
D. VLSI
Answer: Option B
-------------------------------------------------------------------------------51. A classification of ICs with complexities of 100 to 10,000 equivalent gates per chip
is known as ________.
A. SSI
C. LSI
B. MSI
D. VLSI
Answer: Option C