proprietà delle ferriti:
Material  Basic-powder  Permeability (µ)  Freq.Range (MHz)  Color-Code
   0        Phenolic         1               100 - 300        Tan
   1        Carbonyl C       20              0.5 - 5.0        Blue
   2        Carbonyl E       10              2.0 - 30.0       Red
   3        Carbonyl HP      35             0.05 - 0.5        Gray
   6        Carbonyl SF      8                10 - 50         Yellow
   7        Carbonyl TH      9               5.0 - 35.0       White
   10       Carbonyl W       6                30 - 100        Black
   12       Synthetic Oxide  4                50 - 200        Green/White
   15       Carbonyl GS6     25             0.10 - 2.0        Red/White
   17       Carbonyl         4                50 - 200        Blue/Yellow
   26       Special          75           LF Filters,Chokes   Yellow/White