Magnetic materials — In general systems and specifically in magnetics, hysteresis refers to which behavior?
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Alead between cause and effect
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Blag between cause and effect
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Clead between voltage and current
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Dlag between voltage and current
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Einstantaneous proportional response
Answer
Correct Answer: lag between cause and effect
Explanation
Introduction:Hysteresis appears in magnetic cores, ferroelectrics, and other systems where the output depends on current and past inputs. In transformers and inductors, magnetic hysteresis directly affects core losses and B-H loop behavior.
Given Data / Assumptions:
- Considering magnetization M vs. applied magnetic field H.
- Core material exhibits a B-H loop (non-linear, path-dependent response).
- Sinusoidal steady-state or cycling conditions.
Concept / Approach:
Hysteresis is a path-dependent lag: the material’s response (magnetization/flux density) does not follow the instant value of excitation alone; it lags and depends on history. The loop area represents hysteresis loss per cycle, contributing to heating at a rate proportional to frequency and core volume.
Step-by-Step Solution:
Apply increasing H → B increases along an ascending curve.Reduce H → B does not return the same path; remanence remains at H = 0.Reverse H → coercive field is required to drive B to zero.The enclosed loop area is the hysteresis loss; lag behavior defines hysteresis.Verification / Alternative check:
Core datasheets specify hysteresis loops and coercivity. Loss modeling (Steinmetz parameters) includes a hysteresis term proportional to frequency and peak flux, confirming the lagging, path-dependent nature.
Why Other Options Are Wrong:
- lead between cause and effect: Opposite of hysteresis behavior.
- lead/lag between voltage and current: That describes reactive phase shift, not hysteresis per se.
- instantaneous proportional response: Would be a linear, memoryless system, not hysteretic.
Common Pitfalls:
- Confusing hysteresis (memory effect) with phase shift from reactance.
- Ignoring that hysteresis persists even at low frequency, though losses scale with frequency.
Final Answer:
lag between cause and effect