Definition of toggle operation in flip-flops: A clocked flip-flop is said to “toggle” when, after a triggering edge, its outputs transition in which manner?

Introduction / Context:
“Toggle” is a key term used with T flip-flops and J–K flip-flops when J = K = 1. It describes a deterministic inversion of the stored bit on each active clock event. Recognizing this behavior is central to building counters, frequency dividers, and state machines that rely on predictable bit inversion per clock cycle.

Given Data / Assumptions:

• Edge-triggered flip-flop with a toggle condition (e.g., T = 1 or J = K = 1).
• Outputs are complementary: Q and Q̄.
• Idealized digital behavior without metastability is assumed.

Concept / Approach:
Toggle means the next state equals the logical NOT of the current state: Q_next = NOT(Q_current). In J–K terms, with J = K = 1, the excitation table specifies toggling. This property is exploited in ripple and synchronous counters, where each stage toggles to divide frequency or to propagate carries under controlled logic.

Step-by-Step Solution:

Verification / Alternative check:
Review J–K excitation tables or T flip-flop characteristic equations; both demonstrate inversion on each qualifying clock. Simulations of binary counters likewise show a divide-by-2 action caused by toggling each clock.

Why Other Options Are Wrong:

• Remain the same: That describes a “hold,” not a toggle.
• Force to 1 or force to 0: Those are set and reset behaviors, not toggling.
• High-impedance: Flip-flops do not normally present tri-state outputs.

Common Pitfalls:
Confusing toggle with asynchronous set/reset; forgetting that toggling happens only at the qualifying clock edge; overlooking setup/hold constraints that must be satisfied to ensure reliable toggling.

Final Answer:
change to opposite states