Design Formulas

Design Information

Ae：有效磁粉芯面积（cm²）与磁芯的横截面积相等（cross section area）
le:有效磁路长度或称平均磁路长度（cm）（mean magnetic path length）
V:磁芯体积：（cm³）(core volume)
OD：磁芯外径（cm）（outside diameter of core）
ID:磁芯内径（cm）(inside diameter of core)
Ht：磁芯高度（cm）
W:磁芯最小窗口面积（cm²）
1英寸（inches）=10³mil=25.4mm

In magnetics,permeability is the ability of a material to conduct flux.The magnetitude of the permeability at a given induction is a measure of the ease with which a core material can be magnetized to that induction.It is defined as the ratio of the flux density Bto the magnetizing force H.

µe：有效磁导率（无量纲）permeability
B:磁通量密度（高斯Gauss）flux density(Gauss)
H:磁场强度（奥斯特O_e）magnetizing(O_e)

Neu Flux Cores的电感系数值是以1000圈时为测试依据，其中电感系数偏差通常在±8%之间。
The inductance of a wound core at a given number of turns is calculated using the following formula

L=0.4πµeN₂Ae*10^-2/le
Ln=Al&N<2>*10^-3L:电感量（µH）1H=10³mH=10⁶µH=10⁹nH inductance(µH)
Al：额定电感量（nH/N²）nominal Inductance(nH/N²)
µe:有效磁芯截面积 effective cores section area(cm²)
Ae:有效磁路长度 mean magnetic path length(cm)
N:线圈数： number of turns
Ln:在N圈时的电感量（µH）Inductance at N turns(µH)

Ampere's Law relates magnetizing force(H)to current,number of turns and magnetic path length.

H:磁场强度（Oersteds）magnetizing force(oersteds)

N:圈数 number of turns

I:电流（A）peak magnetizing current(amperes)

Le:磁路长度（cm） mean magnetic path length(cm)

1Oersted=0.7958A/cm

The Qfactor is defined as the ratio of reactance to the effective resistance for inductor and thus indicates its quality.The Qof wound core can be calculated using the following formula,when neglecting the effects of self-resonance caused by the distributed capacitance resulting from the differential voltage between adjacent turns.

Q:品质因数 quality factor

L:电感量（H）inductance(henries)

ω:2πf(Hz)2π frequency(hertz)

Rdc:绕线直流电阻（Ω）DC winding resistance(ohms)

Rac:由于磁粉芯损耗而产生的阻抗（Ω）resistance due to core loss(ohms)

Rcd:由于绕线中介电损耗而产生的阻抗（Ω）resistance due to winding dielectric loss(ohms)

The corresponding parameter for the induces magnetic field in an area perpendicular to the flux density is determined by the field strength permeability of the medium in which it is measured.

Bpk:最大磁通密度峰值（高斯Gauss）maximum flux density(gauss)
Erms:通过绕正弦电压有效值（Vrms）sinusoidal RMS voltage across winding(Vrms)
N:圈数 number of turns
Ae:有效磁粉芯截面积（cm²）cross section area(cm²)
f：正弦波形电压频率（Hz）frequency(hertz)
1特斯拉（T）=10⁴高斯（）Gauss=10³mT

Powder cores have low hysteres is loss,minimizing signal distoion,and low residual loss.The total core loss at low.The core loss is calculated from the following legg's equation.

Rac:由磁芯损耗产生的有效电阻（Ω）resistance due tp core loss(ohms)

μe:有效磁导率 permeability

L:电感量（H）inductance(H)

a:磁滞损耗系数 hysteresis loss coefficient

Bpk:AC磁通密度峰值（高斯Gauss）maximum flux density(gauss)

c:剩磁损耗系数 residual loss coefficient

f:频率（Hz）frequency(hertz)

e:涡流损耗系数：eddy loss coefficient