Digital Logic and Design MCQs with Answers
Practice important Digital Logic and Design MCQs with answers and explanations.
Multiple Choice Questions
Q371: What is the Boolean expression for the Sum output of a Full-Adder?
- A: A ⊕ B ⊕ C
- B: (A ⊕ B) + C
- C: (A · B) ⊕ C
- D: A ⊕ (B ⊕ C)
View Answer
A
Q372: Which ICs are used for 4-bit parallel adders with Look-Ahead Carry Circuitry?
- A: 74LS83A and 74LS283
- B: 74LS00 and 74LS04
- C: 74LS08 and 74LS32
- D: 74LS02 and 74LS20
View Answer
A
Q373: What is the purpose of Look-Ahead Carry Circuits?
- A: To delay carry propagation
- B: To speed up carry propagation
- C: To eliminate carry propagation
- D: To detect carry errors
View Answer
B
Q374: In a 4-bit Parallel Adder, what is the delay caused by carry propagation through the full adders?
- A: 30 nsec
- B: 60 nsec
- C: 90 nsec
- D: 120 nsec
View Answer
D
Q375: How are Look-Ahead Carry Generator circuits designed to speed up calculations?
- A: By using additional XOR gates
- B: By using additional AND gates
- C: By using additional OR gates
- D: By evaluating carry generation in parallel
View Answer
B
Q376: What is the delay for the carry output C4 in a 4-bit Look-Ahead Carry Generator circuit?
- A: After 1 gate delay
- B: After 2 gate delays
- C: After 3 gate delays
- D: After 4 gate delays
View Answer
B
Q377: What does BCD stand for in digital systems?
- A: Binary Coded Decimal
- B: Binary Code Decimal
- C: Binary Complete Decimal
- D: Binary Count Decimal
View Answer
A
Q378: How many 4-bit combinations are considered valid in BCD?
- A: 6
- B: 10
- C: 16
- D: 8
View Answer
B
Q379: What is the purpose of adding a 6 to the result in BCD Addition?
- A: To correct an overflow error
- B: To convert an invalid BCD number to a valid one
- C: To decrease the sum by 6
- D: To increase the digit by 6
View Answer
B
Q380: What circuit checks if the output of the first Adder has exceeded 9 in BCD Addition?
- A: Invalid BCD Number Detector
- B: Carry Look-Ahead Circuit
- C: Parity Checker
- D: Overflow Detector
View Answer
A