Q1: MULTIPLE CHOICE. Choose the one alternative that best completes the statement or answers the question. 1) In terms of digital logic, a HIGH voltage usually represents A) an illegal condition. B) a one. C) a zero. D) an open. Answer: B 2) In terms of digital logic, a LOW voltage usually represents A) an open. B) an illegal condition. C) a zero. D) a one. Answer: C 3) The Boolean equation for an AND gate is ________. A) AB = X B) A/B = X
C) A - B = X
D) A + B = X
Answer: A 4) Which logic function is represented by the equation AB = X? A) AND B) clock C) adder
D) OR
Answer: A 5) Which logic function is represented by the equation ABCD = X? A) inverter B) AND C) clock
D) OR
Answer: B 6) Which set of outputs is correct for this AND truth table?
A 0 0 1 1
B 0 1 0 1
X ? ? ? ?
A) 0 1 1 1
B) 0 1 0 1
C) 0 0 0 1
D) 0 0 0 0
C) A - B = X
D) AB = X
Answer: C 7) The Boolean equation for an OR gate is ________. A) A/B = X B) A + B = X Answer: B 8) Which logic function is represented by the equation A + B = X? A) AND B) OR C) switch Answer: B
1
D) clock
9) In order to produce a LOW output, an OR gate requires A) all inputs to be HIGH. C) any input to be LOW.
B) all inputs to be LOW. D) any input to be HIGH.
Answer: B 10) Which set of outputs is correct for this OR 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 1 1 0
D) 0 1 0 1
Answer: B 11) Waveforms A and B represent the inputs to an AND gate. During which time interval will the output from the gate (X) be HIGH?
A) time interval 1
B) time interval 2
C) time interval 4
D) time interval 5
C) inverter
D) cannot tell
Answer: B 12) Which logic gate is described by the following truth table?
A 0 0 1 1
B 0 1 0 1
X 0 1 1 1
A) AND
B) OR
Answer: B
2
13) Waveforms A and B represent the inputs to an AND gate. During which time intervals will output from the gate (X) be LOW?
A) time intervals 2 and 3 C) time intervals 1 and 2
B) time intervals 1 and 4 D) time intervals 1 and 3
Answer: D 14) Waveforms A and B represent the inputs to an OR gate. During which time intervals will the output from the gate (X) be LOW?
A) time intervals 1 and 3 C) time intervals 1 and 2
Wa
B) time intervals 1 and 4 D) It is never low.
Answer: D 15) Waveforms A and B represent the inputs to an OR gate. During which time interval will the output from the gate (X) be LOW?
A) time interval 1
B) time interval 3
C) time interval 4
D) time interval 5
Answer: B 16) Waveforms A and B represent the inputs to an AND gate. During which time interval will the output from the gate (X) be HIGH?
A) time interval 1
B) time interval 3
C) time interval 4
Answer: D
3
D) time interval 5
17) Waveforms A and B represent the inputs to an OR gate. During which time interval(s) will the output from the gate (X) be HIGH?
A) time interval 4 C) time intervals 3 and 5
B) time intervals 2 and 3 D) never
Answer: C 18) Which truth table is correct for an inverter? A) B) input output input output 0 0 0 0 1 1 1 0
C)
input 0 1
output 1 1
D)
input 0 1
Answer: D 19) The truth table for a three-input OR gate contains ________ entries. A) 9 B) 6 C) 8 Answer: C
4
D) 3
output 1 0