Magenetic properties

Inductance and Turns formula

The turns required for a given inductance or a inductance for a given number of turns can be calculated from:

N=100 √ L/AL                   or              L=AL{N2/10.000}

Were N = number of turns;

         L = desired inductance (μH)

         AL = inductance index (μH per 100 turns)

AL Values (μH per 100 turns)

MIX
  Size  26    3        15       1      2       7      6       10      12      17      0  
T-12     na    60   50   48   20   18  17  12 7.5 7.5 3.0
T-16  145   61   55   44   22   na  19  13 8.0 8.0 3.0
T-20  180  76   65   52   27   24  22  16 10.0 10.0 3.5
T-25  235  100   85   70   34   29  27  19 12.0 12.0 4.5
T-30  325  140   93   85   43   37  36  25 16.0 16.0 6.0
T-37  275  120   90   80   40   32  30  25 15.0 15.0 4.9
T-44  360  180  160  105   52  46    42  33  18.5  18.5  6.5
T-50  320  175  135  100   49   43   40   31  18.0  18.0  6.4
T-68  420  195  180  115  57   52   47   32  21.0  21.0  7.5
T-80  450  180  170  115  55   50   45   32  22.0  22.0  8.5
T-94  590  248  200  160  84   na   70   58  32.0  na  10,6

 Magnetic Properties Irion Powder Cores

Most powdered-irion toroid-cores that radio amateurs use are manufactored by Micrometals, who uses paint to identity the material used in the core. The Micrometal color code can find in the table below.

Mix      Color Material  μ    

Temp stability

(ppm/0C)

 f (MHz)   Notes
 26  yellow/white     hydrogen reduced 75  825  dc - 1  Used for EMI filters and dc chokes
 3  gray  carbonyl hp  35  370 0,05 - 0,50    Excellent stability, good Q for lowe frequencies
 15  red/white  carbonyl gs6  25  190  0,1 - 2  Excellent stability, good Q
 1  bleu  carbonyl c  20  280  0,5 - 5  Similar to mix 3, but better stabillity
 2  red  carbonyl e  10  95  2 - 30  High Q material
 7  white  carbonyl th  9  30  3 - 35  Similar to MIX-2 and Mix-6, but better temp stabillity
 6  yellow  carbonyl sf  8  35  10 - 50  Very good Q and temp. stability for 20 - 50 Mhz
 10  black  Powdered-iron W   6  150  30 - 100  Good Q and stability for 40 - 100 MHz
 12  green/white  Synthetic oxide  4  170  50 - 200  Good Q, moderate temp stability
 17  bleu/yellow  carbonyl  4  50  40 - 180  Similar to Mix-12, better temp. stability, Q drops about 10% above 50 MHz, 20% above 100MHz

0

tan

phenolic

1

0

100 - 300     

 Inductance may vary greatly with winding technique