Difficulty: Easy
Correct Answer: D flip-flop
Explanation:
Introduction / Context:Flip-flops can be transformed by constraining their inputs. An SR latch/flip-flop with both inputs driven by complementary versions of the same signal behaves as a D (data) flip-flop, capturing the single input value.
Given Data / Assumptions:
Concept / Approach:With S = D and R = not D, only one of S or R can be asserted at a time. When D = 1, set is asserted and the device stores 1; when D = 0, reset is asserted and it stores 0. This exactly matches D flip-flop semantics: on the active control (clock or enable), Q_next = D.
Step-by-Step Solution:
Introduce an inverter so inputs are complementary. Map cases: D=1 → S=1,R=0 → Q set to 1; D=0 → S=0,R=1 → Q reset to 0. On each active transition/level, Q captures D → D-type behavior.Verification / Alternative check:Truth behavior of a D flip-flop is Q_next = D at the sampling event. The constrained SR realization reproduces this, confirming equivalence.
Why Other Options Are Wrong:
JK: requires independent J and K inputs, not forced complements of one signal. T: toggles when T=1; this construction does not toggle— it stores D. Master–slave JK: a specific clocked configuration of JK, not applicable here.Common Pitfalls:Driving S and R high simultaneously (forbidden); omitting proper gating/clocking when building edge-triggered D FF from level-sensitive latches.
Final Answer:D flip-flop
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