Dimension Tolerance
 
Toroids OD(mm) ID(mm) HT(mm)
C03～C06 ±0.3 ±0.3 ±0.3
C07～C19 ±0.5 ±0.5 ±0.5
C21～C33 ±0.6 ±0.6 ±0.6
C34～C57 ±0.75 ±0.75 ±0.75
Magnetic Design Formulas
 
Inductance Considerations

where
　　L=inductance(Henries)
　　μ=core permeability
　　N=number of turns
　　Ae=core cross section(c㎡)
　　Le=core magnetic path length(cm)

where
　　Ln=inductance for N turns (μH)
　　AL=nominal inductance (nH/N2)
 
Voltage-Flux Density-Frequency (Faraday's Law)
Where
　　Bmax=maximum flux density
　　Erms=equivalent rms voltage across coil
　　N=number of turns
　　A=core cross section(c㎡)
　　f=frequency(herz)
 
Ampere's Law
where
　　H=magnetizing force
　　N=number of turns
　　I=peak current(amperes)
　　L=mean magnetic path(cm)
where
　　μ=relative premeability
　　B=flux denxity(gausses)
　　H=magnetizing force(oersteds)
 
Mean Magnetic Path Length
 
OD=outside diameter of core(cm)
ID=inside diameter of core(cm)
HT=core height(cm)
A=core cross section(c㎡)
l=mean magnetic path length(cm)