Core Materials for >1MHz
General Material Properties
| Material | Reference Permeability |
Powder Type | Temp Coef of Perm (+ppm/C°) |
Density gm/cm |
Max Frequency (MHz) |
Relative Cost | Color Code Toroid |
|---|---|---|---|---|---|---|---|
| -2 | 1 | Carbonyl Iron | 95 | N/A | N/A | N/A | Red/Clear |
| -8 | 20 | Carbonyl Iron | 255 | 6.4 | 10 | 3.8 | Yellow/Red |
| -14 | 10 | Iron | 150 | 5 | 45 | 2.2 | Black/Red |
| -18 | 35 | Iron | 385 | 6.5 | 5.0 | 3.3 | Green/Red |
| -19 | 9 | Iron | 650 | 5.0 | 17 | 2.2 | Red/Green |
| -26 | 8.5 | Iron | 95 | 5.0 | 55 | 3.6 | Yellow/White |
| -30 | 9 | Iron | 255 | 5.0 | 50 | 3.0 | Green/Gray |
| -34 | 35 | Iron | 150 | 6.5 | 5.0 | 3.1 | Gray/Blue |
| -35 | 6 | Iron | 385 | 4.9 | 83 | 5.5 | Yellow/Gray |
| -38 | 14 | Iron | 650 | 5.2 | 20 | 2.8 | Gray/Black |
| -40 | 60 | Iron | 950 | 6.9 | 0.38 | 1.0 | Green/Yellow |
| -45 | 100 | Iron | 1043 | 7.2 | 0.34 | 2.6 | Black/Black |
| -52 | 75 | Iron | 650 | 7.0 | 0.59 | 1.1 | Green/Blue |
Material Magnetic Characteristics
| Material | Bsat (G) | H (Oe) at 80% μi |
%μi at H=50 (Oe) |
μ effective at H=50 (Oe) |
|
|||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| -2 | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | N/A | |||||
| -8 | 17,500 | 221 | 97 | 19 | 45 | 59 | 31 | 21 | 107 | |||||
| -14 | 14,800 | 673 | 99 | 10 | 19 | 32 | 18 | 9 | 27 | |||||
| -18 | 17.600 | 101 | 92 | 32 | 45 | 59 | 31 | 21 | 107 | |||||
| -19 | 14,800 | 673 | 99 | 9 | 19 | 32 | 19 | 20 | 186 | |||||
| -26 | 14,800 | 1006 | 100 | 8 | 19 | 32 | 18 | 9 | 26 | |||||
| -30 | 14,800 | 778 | 100 | 9 | 19 | 32 | 18 | 9 | 27 | |||||
| -34 | 17,600 | 101 | 92 | 32 | 45 | 59 | 32 | 22 | 123 | |||||
| -35 | 14,600 | 2201 | 100 | 6 | 19 | 32 | 18 | 9 | 24 | |||||
| -38 | 15,200 | 406 | 99 | 14 | 19 | 32 | 18 | 11 | 49 | |||||
| -40 | 17,600 | 101 | 92 | 32 | 45 | 59 | 32 | 22 | 123 | |||||
| -45 | 14,600 | 2201 | 100 | 6 | 19 | 32 | 18 | 9 | 24 | |||||
| -52 | 15,200 | 406 | 99 | 14 | 19 | 32 | 18 | 11 | 49 | |||||
- ‐2 & ‐14 Materials: The low permeability of these materials will result in lower operating AC flux density than other materials with no additional gap‐loss. The ‐14 Material is similar to ‐2 Material with a higher permeability.
- ‐8 Material: This material has low core loss and good linearity under high bias conditions. A good high frequency material, also the highest cost iron powder material.
- ‐18 Material: This material has low core loss similar to the ‐8 Material with higher permeability and a lower cost. Good DC saturation characteristics.
- ‐19 Material: An inexpensive alternate to the ‐18 Material with the same permeability and somewhat higher core losses.
- ‐26 Material: A very popular material, it is a cost‐effective general purpose material that is useful in a wide variety of power conversion and line filter applications.
- ‐30 Material: The good linearity, low cost and relatively low permeability of this material make a popular choice for high power UPS applications.
- ‐34, ‐35 Materials: An inexpensive alternate to the ‐8 Material where high frequency core loss is not critical. Both ‐34 & ‐35 Materials have good linearity with high bias.
- ‐38 Material: Similar to the ‐26 Material with higher permeability.
- ‐40 Material: The least expensive iron powder material, characteristics similar to the ‐26 Material with a lower permeability. Most popular is large sizes.
- ‐45 Material: The highest permeability iron powder material available. Consider as a high perm alternate to the ‐52 Material with slightly higher core losses.
- ‐52 Material: This material has lower core losses at high frequency and the same permeability as the ‐26 Material. It is popular for high frequency choke designs and available in a wide variety of geometries.
Initial Permeability (µi) vs. DC
Magnetizing Force
Percent Initial Permeability (%µi) vs.
DC Magnetizing Force
Percent Initial Permeability (%µi) vs. Peak AC
Flux Frequency
Initial Permeability (µi) vs Frequency (Hz)
BH Curves
Material Frequency Range
