In multivibrator terminology, an astable multivibrator (with no stable states) is commonly referred to as what kind of multivibrator?

Introduction:
Multivibrators are fundamental timing and waveform-generation circuits. Understanding the difference between astable, monostable, and bistable configurations is key to selecting the right building block for clocks, pulse generators, and timing logic. This question focuses on the common alias for an astable multivibrator.

Given Data / Assumptions:

• Astable multivibrator has no stable state.
• It alternates between two quasi-stable states continuously.
• Implemented with transistors, op-amps, or timers (e.g., 555) with RC timing.

Concept / Approach:
An astable multivibrator oscillates autonomously, requiring no external trigger once powered. Consequently, it is called a free-running multivibrator. In contrast, a monostable (one-shot) has one stable state and produces a single pulse when triggered; a bistable (flip-flop) has two stable states and toggles between them upon triggering.

Step-by-Step Solution:

Verification / Alternative check:
Examining timing equations (e.g., for a 555 astable: T = 0.693 * (RA + 2RB) * C) shows output repeats indefinitely; no external triggers are needed, confirming free-running behavior.

Why Other Options Are Wrong:

• One-shot (monostable): Needs a trigger; not free-running.
• Bistable: Two stable states; not oscillatory by itself.
• Monostable: Same as one-shot; not continuously oscillatory.

Common Pitfalls:
Confusing the names because all use RC timing; assuming any RC network oscillates without the required feedback polarity; overlooking that astable implies no rest state.

Final Answer:
Free-running multivibrator.