The truth table for an S-R flip-flop has how many VALID entries?
The truth table for an S-R flip-flop has how many VALID entries?
Answer: C. 3 — Answer: 3 valid entries. Reason: The inputs to consider are Set (S) and Reset (R). There are four possible input pairs: 00, 01, 10, and 11. The pair with both…
- A.
1
- B.
2
- C.
3
- D.
4
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Correct answer: C
Answer: 3 valid entries.
Reason: The inputs to consider are Set (S) and Reset (R). There are four possible input pairs: 00, 01, 10, and 11. The pair with both S and R equal to 1 is undefined (invalid) for the basic S–R flip-flop, so it is excluded from the valid truth-table entries.
S=0, R=0 → Next state = current state (no change).
S=0, R=1 → Next state = 0 (reset).
S=1, R=0 → Next state = 1 (set).
Note: The current state is used to determine the next state when S and R are both 0, but it is not an additional input combination counted in the S-R truth table. Therefore, there are three valid S-R entries.