GENERAL MATERIAL PROPERTIES Material Mix No. Reference Permeability (µo) Material Density (g/cm3) Relative Cost Color Code -2 10 5.0 2.7 Red/Clear -8 35 6.5 5.0 Yellow/Red -14 14 5.2 3.6 Black/Red -18 55 6.6 3.4 Green/Red -19 55 6.8 1.7 Red/Green -26 75 7.0 1.0 Yellow/White -30 22 6.0 1.4 Green/Gray -34 33 6.2 1.5 Gray/Blue -35 33 6.3 1.4 Yellow/Gray -38 85 7.1 1.1 Gray/Black -40 60 6.9 1.0 Green/Yellow -45 100 7.2 2.6 Black/Black -52 75 7.0 1.4 Green/Blue

< top of page CLICK ON MATERIAL FOR MORE DETAILS   INDUCTANCE RATINGS In this catalog the inductance ratings, also known as AL values, are expressed in nanohenries (10-9 Henries) per turn (N) squared (nH/N2). An example of a conversion from mH for 100 turns to nH/N2 is: 350 µH for 100 turns = 35.0 nH/N(sup)2(/sup) To calculate the number of turns required for a desired inductance (L) in nanohenries (nH) use the following formula:

THERMAL CONSIDERATION Material Mix No. Temp. Coef. of Permeability (+ppm/C°) Coef. of Lin. Expansion (+ppm/C°) Thermal Conductivity (mW/cm-C° -2 95 10 10 -8 255 10 29 -14 150 10 11 -18 385 11 21 -19 650 12 30 -26 825 12 42 -30 510 11 20 -34 565 12 28 -35 665 12 30 -40 950 11 36 -45 1043 12 43 -52 650 12 34

< top of page  CLICK ON MATERIAL FOR MORE DETAILS   TEMPERATURE EFFECTS CWS Bytemark iron powder cores have an organic content and undergo thermal aging. When cores are exposed to or generate elevated temperatures, a permanent decrease in both inductance and quality factor (Q) will gradually occur. The extent of these changes is highly dependent on time, temperature, core size, frequency, and flux density. It is essential that these properties are considered in any design operating at or above 75°C. Iron powder cores tolerate temperatures down to -65°C with no permanent effects. In high power applications where core loss is contributing to the total temperature, a decrease in quality factor will translate into an increase in eddy current losses which will further heat the core and can lead to thermal runaway. Designs where core loss exceeds copper loss should be avoided. Hysteresis losses are unaffected by the thermal aging process. A more thorough and detailed discussion regarding thermal considerations for iron powder core designs is provided in theThermal Aging section of the website. CWS Bytemark has also incorporated a thermal aging predictor into our standard design software. Please contact us directly to receive a free copy or download directly from our web site at http://www.bytemark.com. Furthermore, we are also pleased to provide free design consultation. < top of page FINISH The toroidal and bus bar cores listed in this catalog are provided with a protective coating. The T14, T16 and T20 size cores are coated under vacuum with Parylene C. The larger cores are coated with a two color code finish that is UL approved for Flame Class UL94V-0 per file #E140098 (S). A copy of the Yellow card can be provided upon request. All finishes have a minimum dielectric strength of 500 Vrms at 60 Hz and resist most cleaning solvents. Extended exposure to certain solvents may have detrimental effects. The toroidal cores can be double or triple coated for greater dielectric strength. We can also provide uncoated cores upon special request. Please contact the factory for information on optional finishes or core caps for larger size toroids. The E-cores and U-cores are treated to help resist rust. CWS Bytemark recommends that all uncoated cores should be sheltered from high humidity or rain since they will eventually form surface rust. Lastly, CWS Bytemark color codes are protected by U.S. trademark law. < top of page