Question

Multivibrator which can produce a very short pulse or a much longer rectangular shaped waveform whose leading edge rises in time with an externally applied trigger pulse is called

• A. \( \text{Astable multivibrator} \)
• B. \( \text{Distable multivibrator} \)
• C. \( \text{Monostable multivibrator} \)
• D. \( \text{Tristable multivibrator} \)

Hint:

Remember the names of multivibrators correspond to the number of *stable* states they possess: \textbullet \ Astable No stable states (continuously oscillates). \textbullet \ Monostable One stable state (produces a single pulse upon trigger, then returns to stable state). Also known as a "one-shot" multivibrator. \textbullet \ Bistable Two stable states (flips between states with each trigger pulse, like a flip-flop).

Answer 1

The Correct Option is C

Multivibrators are electronic circuits used to implement two-state systems like oscillators, timers, and flip-flops. They are categorized based on their stability: 1. Astable Multivibrator: This multivibrator has no stable states. It continuously oscillates between two unstable states, producing a continuous train of pulses (square waves) without any external trigger. Therefore, it does not fit the description of requiring an external trigger for its leading edge. 2. Bistable Multivibrator (or Flip-flop): This multivibrator has two stable states. It remains in one state until an external trigger pulse causes it to switch to the other stable state. It requires a trigger for each transition and does not produce a pulse of a specific duration related to the trigger. 3. Monostable Multivibrator: This multivibrator has one stable state and one quasi-stable (unstable) state. It remains in its stable state indefinitely until an external trigger pulse is applied. Upon receiving a trigger, it temporarily transitions to its quasi-stable state for a predetermined period, generating a single output pulse of a specific duration. After this period, it automatically returns to its stable state. The leading edge of this output pulse is synchronized with the externally applied trigger pulse. This perfectly matches the description provided in the question. 4. Tristable Multivibrator: This term is not standard in basic multivibrator classification. The common types are Astable, Monostable, and Bistable. Based on the characteristics described (requires an external trigger, produces a pulse whose leading edge rises with the trigger, and can produce pulses of varying duration), the circuit is a Monostable multivibrator.