Flip-flop classification: The S–R, D-type, and J–K flip-flops are all examples of which class of multivibrator?

Introduction / Context:
Multivibrators are categorized by the number of stable states they possess. Recognizing where flip-flops like S–R, D, and J–K fit aids in understanding storage elements and timing circuits.

Given Data / Assumptions:

• S–R, D, and J–K flip-flops are considered.
• We compare against astable, monostable, and bistable classes.
• Standard digital logic behavior is assumed.

Concept / Approach:
A bistable multivibrator has two stable states and remains in either until an input command causes a transition. This is exactly what flip-flops do: they store one bit of information (Q = 0 or Q = 1) until clocked or commanded to change. Astable multivibrators have no stable state and oscillate freely (e.g., RC oscillators); monostable multivibrators have one stable state and require a trigger to produce a single pulse returning to the stable state (one-shots).

Step-by-Step Solution:

Verification / Alternative check:
Any flip-flop datasheet or text defines them as bistable storage elements. Timing diagrams show persistence in the current state absent a triggering event.

Why Other Options Are Wrong:
Astable: oscillators, not memory elements.

Monostable: one-shot pulse generators, not two-state storage.

Tristable: not a standard multivibrator class; “tri-state” refers to outputs with a high-impedance third state, not device stability.

Common Pitfalls:
Confusing “tri-state outputs” (bus drivers) with “multivibrator stability classes.” Flip-flops can have tri-stated outputs yet remain bistable devices.

Final Answer:
Bistable multivibrators