Digital Logic and Design MCQs with Answers
Practice important Digital Logic and Design MCQs with answers and explanations.
Multiple Choice Questions
Q721: How is the test vector used to specify a logic 0 output when the Clear input is logic 0?
- A: By setting all inputs to 1
- B: By setting the Clear input to 0
- C: By setting the clock signal
- D: By setting the enable signal
View Answer
B
Q722: What type of flip-flop was used in the original 3-bit Up/Down Counter?
- A: D flip-flop
- B: T flip-flop
- C: SR flip-flop
- D: JK flip-flop
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D
Q723: In the 3-bit Up/Down Counter, what input controls the counting direction?
- A: Clock
- B: Clear
- C: X input
- D: Q0 input
View Answer
C
Q724: Which equation defines the D1 input in the 3-bit Up/Down Counter?
- A: D1 = Q1Q0X
- B: D1 = Q0 ⊕ Q1 ⊕ X
- C: D1 = Q2Q0X
- D: D1 = Q0Q1X
View Answer
B
Q725: What state does the elevator system start in according to the state diagram?
- A: Up State
- B: Close 1 State
- C: Wait 2 State
- D: Wait 1 State
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D
Q726: What does the ABEL statement [Q0, Q1, Q2].CLK = clock define?
- A: Synchronous reset
- B: Asynchronous reset
- C: State change on clock
- D: Clock initialization
View Answer
C
Q727: What is the output of the elevator system in the Up State (U)?
- A: Door=0, Motion=0, Dir=0
- B: Door=1, Motion=0, Dir=0
- C: Door=0, Motion=1, Dir=1
- D: Door=1, Motion=1, Dir=0
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D
Q728: Which state represents the elevator waiting with the door open on floor 2?
- A: Close 2 State (C2)
- B: Wait 1 State (W1)
- C: Wait 2 State (W2)
- D: Down State (D)
View Answer
C
Q729: The _____________ input overrides the ________ input
- A: Asynchronous, synchronous
- B: Synchronous, asynchronous
- C: Preset input (PRE), Clear input (CLR)
- D: Clear input (CLR), Preset input (PRE)
View Answer
A
Q730: The essential difference between synchronous and asynchronous counters is that the synchronous counters ________.
- A: Use a clock pulse to control changes
- B: Do not use a clock pulse to control changes
- C: Operate at varying speeds
- D: Are used for special applications
View Answer
A