Monostable (one-shot) multivibrator concept: A one-shot circuit is also known as a timer because a trigger produces a single pulse of defined width. Evaluate the statement.
-
ACorrect
-
BIncorrect
-
COnly true for astable circuits
-
DOnly true for bistable latches
Answer
Correct Answer: Correct
Explanation
Introduction / Context:A one-shot, formally called a monostable multivibrator, is fundamental in digital timing. When triggered, it produces one output pulse whose width is set by external components or internal timing, so many practitioners casually call it a timer. This question asks you to judge that naming and understand why it is reasonable.
Given Data / Assumptions:
- A one-shot (monostable) has one stable state and one quasi-stable state.
- On a trigger edge, the output moves to the quasi-stable state for a defined duration (pulse width), then returns to the stable state.
- Timing is set by RC components or internal references in IC one-shots.
Concept / Approach:The essence of a timer is to create a time interval. A one-shot does exactly that on demand: it generates a pulse with width t_w determined by design parameters (e.g., t_w = k * R * C for many devices). That pulse can debounce inputs, stretch narrow edges, create delays, or gate logic for a known time.
Step-by-Step Solution:
Recognize that “timer” describes a function, not necessarily a specific topology.A monostable generates a single, timed output pulse when triggered.This timed behavior is used to implement delays, pulse stretching, and interval generation.Therefore, calling a one-shot a “timer” is appropriate in context.Verification / Alternative check:Datasheets for classic one-shot ICs (e.g., 74121/74123/4538) specify equations for pulse width vs. R and C, underscoring the timing role.
Why Other Options Are Wrong:
Incorrect: Contradicts the clear timing behavior of one-shots.Only true for astable circuits: Astable oscillators self-run; a one-shot is trigger-driven.Only true for bistable latches: Bistables hold states; they do not generate timed pulses.Common Pitfalls:Confusing monostable (one-shot) with astable (free-running clock) or bistable (flip-flop/latch). Assuming “timer” means only a 555-type oscillator; it also covers triggered timing intervals.
Final Answer:Correct