Q1: MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) Which logic gate is described by the following truth table?
A 0 0 1 1
B 0 1 0 1
X 1 0 0 0
A) NOR
B) OR
C) AND
D) NAND
Answer: A 2) Waveforms A and B represent the inputs to a NAND gate. During which time interval(s) will the output from the gate (X) be LOW?
A) time intervals 2, 3, and 4 C) time interval 2
B) never D) time intervals 2 and 3
Answer: C 3) Which output is correct for this NOR truth table?
A 0 0 1 1
B 0 1 0 1
X ? ? ? ?
A) 0 0 0 1
B) 0 1 1 1
C) 1 0 0 0
Answer: C
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D) 1 1 1 0
4) Waveforms A and B represent the inputs to a NAND gate. During which time interval(s) will the output from the gate (X) be HIGH?
A) time intervals 1 and 2 C) time intervals 1, 2, 4, and 5
B) time interval 5 D) time interval 3
Answer: C 5) Which logic function can be implemented by connecting an inverter to the output of an OR gate? A) AND B) OR C) NOR D) inverter Answer: C 6) A + 1 = ________. A) 1
B) 0
C) A
D) A
B) 0
C) A
D) A
B) 0
C) A
D) A
B) 0
C) A
D) A
B) 0
C) A
D) A
C) X = A + B
D) X = A + AB
C) X = C + AC
D) X = AC + B
C) X = A B C
D) X = A + B + C
Answer: A 7) A + A = ________. A) 1 Answer: C 8) A ¡ A = ________. A) 1 Answer: B 9) A + A = ________. A) 1 Answer: A 10) A = ________. A) 1 Answer: C 11) The simplest form of X = (A + B)A + AB is ________. A) X = B
B) X = A + B
Answer: A 12) The simplest form of X = AC + C(A + B) is ________. A) X = AC + BC
B) X = A + BC
Answer: B 13) The simplest form of X = (A + B) + AC is ________. A) X = A B
B) X = A + AC
Answer: A 2
14) What is the simplest form of X = A + AC ? A) X = AC
B) X = C
C) X = A + C
D) It is in its simplest form.
Answer: C 15) What is the simplest form of X = AB + AC + BC? A) X = BC + C
B) X = AB + C
C) X = A + BC
D) It is in its simplest form.
Answer: D 16) The simplest form of X = A(B + C) + AB is ________. A) X = AB + AB
B) X = AC + AB
C) X = AC
D) X = B + AC
C) X = AB + AC
D) X = A
C) ABC
D) = A*B*C + A*B*C
Answer: D 17) The simplest form of X = AB + ABC + A(B + C) is ________. A) X = AB + AC + C
B) X = AB + C
Answer: D 18) The simplest form of X = (AB + AC)BC is ________. A) = A*C + B*C B) X = A + B*C Answer: C 19) By using DeMorgan's theorem, X = A(B + C) is simplified to ________. A) X = A + B + C
B) X = ABC
C) X = A + BC
D) X = A(B + C)
Answer: C 20) Which of the following is an example of DeMorgan's theorem? A) AB = A B
B) AB = A + B
C) A B = A + B
D) A + B = A + B
Answer: B 21) Which Boolean expression indicates an inverted gate output? A) A + B
B) A + B
C) A + B
D) A + B
B) A + B
C) A + B
D) AB
B) AB
C) A + B
D) A + B
C) a NOR gate.
D) an inverter.
Answer: A 22) A + AB = ________. A) AB Answer: C 23) A + AB = ________. A) AB Answer: C 24) An AND gate with inverted inputs functions as A) an OR gate. B) a NAND gate. Answer: C
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25) A NAND gate with inverted inputs functions as A) an OR gate. B) a NOR gate.
C) an AND gate.
D) a NAND gate.
C) a NAND gate.
D) an OR gate.
27) A NAND gate with all inputs tied to one signal functions as A) an OR gate. B) a NOR gate. C) an AND gate.
D) an inverter.
Answer: A 26) A NOR gate with inverted inputs functions as A) a NOR gate. B) an AND gate. Answer: B
Answer: D 28) A NAND gate with its output inverted functions as A) an AND gate. B) an inverter.
C) a NOR gate.
D) an OR gate.
C) a NOR gate.
D) an OR gate.
Answer: A 29) A NAND gate with each input inverted functions as A) an AND gate. B) an inverter. Answer: D 30) Which answer is an example of a product-of-sum (POS) expression? A) X = AB + CD B) X = ABC C) X = A + B + C
D) X = (A + B)(C + D)
Answer: D 31) The final output of a product-of-sum (POS) circuit is generated by A) a NOR. B) an OR. C) a NAND.
D) an AND.
Answer: D 32) The final output of a sum-of-products (SOP) circuit is generated by A) a NOR. B) an OR. C) an AND.
D) a NAND.
Answer: B 33) Which answer is an example of a sum-of-products (SOP) expression? A) X = (AB)(CD) B) X = AB + AC C) X = A + B
D) X = (A + B)(C + D)
Answer: B 34) Which Boolean equation expresses the commutative law? A) AB + AC = A(B + C)
B) AB = AB
C) AB = BA
D) A + (B + C) = (A + B) + C
Answer: C 35) A · A = ________. A) 1
B) 0
C) A
D) A
B) 0
C) A
D) A
Answer: C 36) A + 0 = ________. A) 1 Answer: C
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37) Which logic circuit is represented by the Boolean equation A + B + C + D = X? A) OR B) NAND C) Inverter
D) NOR
Answer: D 38) Waveforms A and B represent the inputs to a NAND gate. During which time interval(s) will the output from the gate (X) be HIGH?
A) time interval 5 C) time intervals 1, 2 and 3
B) time interval 4 D) time intervals 4 and 5
Answer: D
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