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Magnetic field of iron core solenoid

  1. Dec 28, 2012 #1
    When we calculate magnetic field of iron core solenoid, should we multiply "relative permeability" or "effective permeability"?

    I thought that we should use relative permeability, but wiki(http://en.wikipedia.org/wiki/Solenoid) says that we should use effective permeability.

    I'm so confused...
    please help me.
  2. jcsd
  3. Jan 1, 2013 #2


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    Permeability μ0 - air/no core

    L = k * μ0 * N2 * A/l

    Relative Permeability μr - factors in the core material

    L = k * μ0 μr * N2 * A/l

    Effective permeability μe - Similar to μr but takes into acount factors such as air gaps, the shape of the core, winding layout. The effective permeability also changes if the core is saturated or fast pulses/high frequencies are involved.

    L = k * μ0 μe * N2 * A/l
    Last edited: Jan 1, 2013
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