Difficulty: Easy
Correct Answer: low eddy current loss
Explanation:
Introduction:
Ferrites are ceramic, iron-oxide-based magnetic materials widely used in high-frequency transformers, inductors, and EMI suppression components. Their electrical and magnetic properties differ significantly from laminated steels, leading to distinct loss mechanisms and design trade-offs in power electronics and RF systems.
Given Data / Assumptions:
Concept / Approach:
Ferrites have very high electrical resistivity compared with metallic cores, which drastically suppresses eddy currents and hence eddy-current loss at high frequency. While hysteresis loss still exists (frequency- and flux-dependent), the high resistivity is the primary reason ferrites outperform solid metals at high frequency. Copper loss pertains to windings, not the core; ferrites typically have lower density than steel and modest thermal conductivity.
Step-by-Step Solution:
Verification / Alternative check:
Core selection guides specify ferrites for high-frequency converters because laminated steel would suffer prohibitive eddy losses at those frequencies, confirming the advantage.
Why Other Options Are Wrong:
“Low copper loss” refers to windings; “low resistivity” is false (they have high resistivity); ferrites are lighter, not of higher specific gravity than iron; thermal conductivity is not “very high.”
Common Pitfalls:
Confusing core losses with winding losses; assuming all magnetic materials behave similarly across frequencies.
Final Answer:
low eddy current loss
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