Difficulty: Easy
Correct Answer: Incorrect
Explanation:
Introduction / Context:
Logic symbols convey device behavior visually. Triangles, bubbles, and other markings have standardized meanings. Misreading these symbols can cause misinterpretation of timing and polarity in flip-flop usage.
Given Data / Assumptions:
Concept / Approach:
“Pulse-triggered” is not a standard label identified by a bubble on Q. In symbols, the triangle at the clock indicates edge-triggering; a bubble on the clock indicates negative-edge sensitivity. A bubble on the Q output simply indicates the output is the complement of Q (often labeled ~Q), not any special triggering mechanism.
Step-by-Step Solution:
Verification / Alternative check:
Standard textbooks and datasheets show D, JK, and T flip-flops with triangle/bubble on the clock to indicate edge and polarity; outputs are labeled Q and ~Q, with a bubble indicating inversion only.
Why Other Options Are Wrong:
Calling it “Correct” confuses output inversion with trigger style. Negative-edge devices are indicated at the clock input, not at Q. Vendor artwork still follows the convention separating output polarity indicators from clock edge indicators.
Common Pitfalls:
Assuming any bubble equals “active-low timing” everywhere; bubbles can indicate inversion for inputs or outputs, and their meaning depends on the pin they adorn.
Final Answer:
Incorrect
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