Monostable 555 timer — how many stable states does it inherently have? Choose the number of stable states for a one-shot (monostable) configuration.
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A0
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B1
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C2
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D3
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E4
Answer
Correct Answer: 1
Explanation
Introduction / Context:A monostable multivibrator (one-shot) is designed to have a single stable state and one quasi-stable state. When triggered, it leaves its stable state temporarily and then returns, producing a pulse. This question checks conceptual understanding of the 555 in monostable mode.
Given Data / Assumptions:
- Device: 555 timer in monostable configuration
- Trigger produces one timing pulse
- After timing, the circuit returns to its resting state
Concept / Approach:The defining property of a monostable is exactly one stable state. The other state exists only transiently (quasi-stable) during the output pulse interval set by R and C.
Step-by-Step Solution:
Identify the operating states: stable (rest), quasi-stable (timed pulse)Count stable states: there is only one stable stateVerification / Alternative check:Compare with astable (no stable state, constant oscillation) and bistable (two stable states, i.e., flip-flop). The monostable sits between them conceptually with exactly one stable state.
Why Other Options Are Wrong:
- 0: Describes astable oscillators, not monostables.
- 2 or 3 or 4: Would imply flip-flop behavior (two) or multi-stable systems; not applicable.
Common Pitfalls:
- Confusing monostable with astable or bistable due to naming similarity.
Final Answer:1