Astable multivibrator behavior — which statement best describes its output? Choose the accurate description of an astable circuit's output state over time.

Introduction / Context:
An astable multivibrator has no stable state. It continuously oscillates between two levels, generating a periodic waveform without requiring external triggers. This question verifies recognition of astable behavior compared to mono- and bi-stable types.

Given Data / Assumptions:

• Astable configuration using active components and RC feedback
• Free-running oscillator behavior expected

Concept / Approach:
By design, astables perpetually charge and discharge timing capacitors, alternately driving the output HIGH and LOW. No trigger input is required to sustain oscillation, unlike monostables and bistables.

Step-by-Step Reasoning:

Verification / Alternative check:
555 in astable mode or cross-coupled inverters with RC produce a continuous square wave, confirming the description.

Why Other Options Are Wrong:

• LOW until triggered / HIGH until triggered: describes monostable behavior.
• Floats until triggered: outputs are not left floating in proper designs.
• Stays latched unless reset: describes bistable flip-flops.

Common Pitfalls:

• Confusing "needs power-up to start" with "needs a trigger"; many astables self-start due to component tolerances.

Final Answer:
constantly switches between two states