Question
How do ferrite and powdered iron compare for use in an inductor core?
Answer Options
- A) Ferrite cores generally have lower initial permeability
- B) Ferrite cores generally have better temperature stability
- C) Ferrite cores generally require fewer turns to produce a given inductance value
- D) Ferrite cores are easier to use with surface-mount technology
Correct Answer: C
Explanation
Ferrite and powdered iron are the two main core materials used to increase the inductance of a coil. Both work by increasing the magnetic permeability (\mu) of the coil’s core, but they differ significantly in their magnetic properties. Ferrites are ceramic compounds, while powdered iron is composed of tiny, insulated iron particles.
Ferrite cores generally have much higher magnetic permeability than powdered iron cores. Consequently, to achieve a required inductance value, Ferrite cores generally require fewer turns to produce a given inductance value compared to a coil wound on a powdered iron core of the same size. This simplifies construction and reduces DC resistance, but ferrites are more prone to saturation and temperature instability.
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