Amidon IRON POWDER TOROIDAL CORES
Iron Powder Material 
Basic Iron Powder 
Material Permeability
µ_{o} 
Temperature Stability
(ppm/°C) 
Resonant
Circuit Frequency Range (MHz) 
Color Code 
0 
Phenolic 
1 
0 
100.0  300.0 
Tan 
1 
Carbonyl C 
20 
280 
0.5  5.0 
Blue 
2 
Carbonyl E 
10 
95 
2.0  30.0 
Red 
3 
Carbonyl HP 
35 
370 
0.05  0.5 
Grey 
6 
Carbonyl SF 
8 
35 
10.0  50.0 
Yellow 
7 
Carbonyl TH 
9 
30 
5.0  35.0 
White 
10 
Carbonyl W 
6 
150 
30.0  100.0 
Black 
12 
Synthetic Oxide 
4 
170* 
50.0  200.0 
Green/White 
15 
Carbonyl GS6 
25 
190 
0.10  2.0 
Red/White 
17 
Carbonyl 
4 
50 
50.00  200.0 
Blue/Yellow 
26 
Special 
75 
882 
LF filters, chokes 
Yellow/White 
Material #17 has been developed as a
temperature stable alternative to the #12.
Frequency ranges shown are for best 'Q'/ Useful over broader frequency
ranges with lower 'Q'.
 MATERIAL #0 (µ=1): Most commonly used for frequencies above 100 MHz. Available in
toroidal form only. Note: Due to the nature of this material the inductance resulting from
the use of a given AL value may not be as accurate as we would like. Inductance vs. number
of turns will vary greatly depending upon the winding technique.
 MATERIAL #1 (µ=20): A Carbonyl 'C' material, very similar to material #3 except that it
has higher volume resistivity and better stability. Available in toroidal form and
shielded coil form.
 MATERIAL #2 (µ=10): A Carbonyl 'E' iron powder material having high volume resistivity.
Offers high 'Q' for the 2 MHz to 20 MHz frequency range. Available in toroidal form and
shielded coil form.
 MATERIAL #3 (µ=35): A Carbonyl 'HP' material having excellent stability and good 'Q'
for the lower frequencies from 50 KHz to 500 KHz. Available in toroidal form and shielded
coil form.
 MATERIAL #6 (µ=8): A Carbonyl 'SF' material. Offers very good 'Q' and temperature
stability for the 20 to 50 MHz frequency range. Available in both toroidal and shielded
coil form.
 MATERIAL #7 (µ=9): A Carbonyl 'TH' material. Very similar to the #2 and #6 materials
but offers better temperature stability than either. Available in both toroidal and
shielded coil form.
 MATERIAL #10 (µ=6): A powdered iron 'W' material. Offers good 'Q' and high stability
for frequencies from 40 MHz to 100 MHz. Available in toroidal form and shielded coil form.
 MATERIAL #12 (µ=4): A Synthetic oxide material which provides good 'Q' and moderate
stability for frequencies from 50 MHz to 200 MHz. If high 'Q' is of prime importance this
material is a good choice. If stability is of a prime importance, consider the #17
material. The #12 material is available in all sizes up to T94, in toroidal form. Not
available in shielded coil form.
 MATERIAL #15 (µ=25): A carbonyl 'GS6' material. Has excellent stability and good 'Q'. A
good choice for commercial broadcast frequencies where good 'Q' and stability are
essential. Available in toroidal form only.
 MATERIAL #17 (µ=4): This is a new carbonyl material which is very similar to the #12
material except tatar it has better temperature stability. However, as compared to the #12
material, there is a slight 'Q' loss of about 10% from 50 MHz to 100 MHz. Above 100 MHz,
the 'Q' will gradually deteriorate to approximately 20% lower. It is available in both
toroidal form and the shielded coil form.
 MATERIAL #26 (µ=75): A Hydrogen Reduced material. Has highest permeability of all of
the iron powder materials. Used for EMI filters and DC chokes. The #26 is very similar to
the older #41 material but can provide and extended frequency range. See AC Line Filter
and CD Choke sections for size, permeability and frequency range information.
MATERIAL 0  Permeability 1, Freq Range 100 MHz 
300 MHz, Color  Tan
Core Number 
O.D.
(inches) 
I.D.
(inches) 
Hgt
(inches) 
l_{e
}(cm) 
A_{e
}(cm)^{2} 
V_{e
}(cm)^{3} 
A_{L} Value
µh/100 Turns 
T120 
.125 
.062 
.050 
.74 
.010 
.007 
3.0 
T160 
.160 
.078 
.060 
.95 
.016 
.015 
3.0 
T200 
.200 
.088 
.070 
1.15 
.025 
.029 
3.5 
T250 
.255 
.120 
.096 
1.50 
.042 
.063 
4.5 
T300 
.307 
.151 
.128 
1.83 
.065 
.119 
6.0 
T370 
.375 
.205 
.128 
2.32 
.070 
.162 
4.9 
T440 
.440 
.229 
.159 
2.67 
.107 
.286 
6.5 
T500 
.500 
.303 
.190 
3.03 
.121 
.367 
6.4 
T680 
.690 
.370 
.190 
4.24 
.196 
.831 
7.5 
T800 
.795 
.495 
.250 
5.15 
.242 
1.246 
8.5 
T940 
.942 
.560 
.312 
6.00 
.385 
2.310 
10.6 
T1060 
1.060 
.570 
.437 
6.50 
.690 
4.485 
19.0 
T1300 
1.300 
.780 
.437 
8.29 
.730 
6.052 
15.0 
Note:
Due to the nature of the '0' material, the inductance resulting from the use of the
given A_{L} value may vary greatly depending upon the winding technique. This may
cause discrepancy between calculated and measured inductance.
MATERIAL 1  Permeability 20, Freq. Range
0.5 MHz to 5 MHz, Color  Blue
Core Number 
O.D.
(inches) 
I.D.
(inches) 
Hgt
(inches) 
X
(cm) 
A_{e
}(cm)^{2} 
V_{e
}(cm)^{3} 
A_{L} Value
µh/100 Turns 
T121 
.125 
.062 
.050 
.74 
.010 
.007 
48 
T161 
.160 
.078 
.060 
.95 
.016 
.015 
44 
T201 
.200 
.088 
.070 
1.15 
.025 
.029 
52 
T251 
.255 
.120 
.096 
1.50 
.042 
.063 
70 
T301 
.307 
.151 
.128 
1.83 
.065 
.119 
85 
T371 
.375 
.205 
.128 
2.32 
.070 
.162 
80 
T441 
.440 
.229 
.159 
2.67 
.107 
.286 
105 
T501 
.500 
.303 
.190 
3.03 
.121 
.367 
100 
T681 
.69 
.370 
.190 
4.24 
.196 
.831 
115 
T801 
.795 
.495 
.250 
5.15 
.242 
1.246 
115 
T941 
.942 
.560 
.312 
6.00 
.385 
2.310 
160 
T1061 
1.060 
.570 
.437 
6.50 
.690 
4.485 
325 
T1301 
1.300 
.780 
.437 
8.29 
.730 
6.052 
200 
T1571 
1.570 
.950 
.570 
10.05 
1.140 
11.457 
320 
T1841 
1.840 
.950 
.710 
11.12 
2.040 
22.685 
500 
T2001 
2.000 
1.250 
.550 
12.97 
1.330 
17.250 
250 
Note:
MATERIAL 2  Permeability 10, Freq. Range
2 MHz to 30 MHz, Color  Red

Core Number 
O.D.
(inches) 
I.D.
(inches) 
Hgt
(inches) 
l_{e
}(cm) 
A_{e
}(cm)^{2} 
V_{e
}(cm)^{3} 
A_{L} Value
µh/100 Turns 
T122 
.125 
.062 
.050 
.74 
.010 
.007 
20 
T162 
.160 
.078 
.060 
.95 
.016 
.015 
22 
T202 
.200 
.088 
.070 
1.15 
.025 
.029 
25 
T252 
.255 
.120 
.096 
1.50 
.042 
.063 
34 
T302 
.307 
.151 
.128 
1.83 
.065 
.119 
43 
T372 
.375 
.205 
.128 
2.32 
.070 
.162 
40 
T442 
.440 
.229 
.159 
2.67 
.107 
.286 
52 
T502 
.500 
.303 
.190 
3.03 
.121 
.367 
49 
T682 
.690 
.370 
.190 
4.24 
.196 
.831 
57 
T802 
.795 
.495 
.250 
5.15 
.242 
1.246 
55 
T942 
.942 
.560 
.312 
6.00 
.385 
2.310 
84 
T1062 
1.060 
.780 
.437 
6.50 
.690 
4.485 
135 
T1302 
1.300 
.950 
.437 
8.29 
.730 
6.052 
110 
T1572 
1.570 
.950 
.570 
10.05 
1.140 
11.457 
140 
T1842 
1.840 
1.250 
.710 
11.12 
2.040 
22.685 
240 
T2002 
2.000 
1.250 
.550 
12.97 
1.330 
17.250 
120 
T200A2 
2.000 
1.405 
1.000 
12.97 
2.240 
29.050 
218 
T2252 
2.250 
1.485 
.550 
14.56 
1.508 
21.956 
120 
T225A2 
2.250 
1.250 
1.000 
14.56 
2.730 
39.749 
215 
T3002 
3.058 
1.925 
.500 
19.83 
1.810 
35.892 
114 
T300A2 
3.048 
1.925 
1.000 
19.83 
3.580 
70.991 
228 
T4002 
4.000 
2.250 
.650 
24.93 
3.660 
91.244 
180 
T400A2 
4.000 
2.250 
1.300 
24.93 
7.432 
185.250 
360 
T5202 
5.200 
3.080 
.800 
33.16 
5.460 
181.000 
207 
MATERIAL 3  Permeability 35, Freq. Range
0.05 MHz to 0.5 MHz, Color  Gray

Core Number 
O.D.
(inches) 
I.D.
(inches) 
Hgt
(inches) 
l_{e
}(cm) 
A_{e
}(cm)^{2} 
V_{e
}(cm)^{3} 
A_{L} Value
µh/100 Turns 
T123 
.125 
.062 
.050 
.74 
.010 
.007 
60 
T163 
.160 
.078 
.060 
.95 
.016 
.015 
61 
T203 
.200 
.088 
.070 
1.15 
.025 
.029 
76 
T253 
.255 
.120 
.096 
1.50 
.042 
.063 
100 
T303 
.307 
.151 
.128 
.183 
.065 
.119 
140 
T373 
.375 
.205 
.128 
2.32 
.070 
.162 
120 
T443 
.440 
.229 
.159 
2.67 
.107 
.286 
180 
T503 
.500 
.303 
.190 
3.03 
.121 
.367 
175 
T683 
.690 
.370 
.190 
4.24 
.196 
.831 
195 
T803 
.795 
.495 
.250 
5.15 
.242 
1.246 
180 
T943 
.942 
.560 
.312 
6.00 
.385 
2.310 
248 
T1063 
1.060 
.570 
.437 
6.50 
.690 
4.485 
450 
T1303 
1.300 
.780 
.437 
8.29 
.730 
6.052 
350 
T1573 
1.570 
.950 
.570 
10.05 
1.140 
11.457 
420 
T1843 
1.840 
.950 
.710 
11.12 
2.040 
22.685 
720 
T2003 
2.000 
1.250 
.550 
12.97 
1.330 
17.250 
425 
T200A3 
2.000 
1.250 
1.000 
12.97 
2.240 
29.050 
460 
T2253 
2.250 
1.405 
.550 
14.56 
1.508 
21.956 
425 
MATERIAL 6 Permeability 8, Freq. Range
10 MHz to 50 MHz, Color  Yellow

Core Number 
O.D.
(inches) 
I.D.
(inches) 
Hgt
(inches) 
l_{e
}(cm) 
A_{e
}(cm)^{2} 
V_{e
}(cm)^{3} 
A_{L} Value
µh/100 Turns 
T126 
.125 
.062 
.050 
.74 
.010 
.007 
17 
T166 
.160 
.078 
.060 
.95 
.016 
.015 
19 
T206 
.200 
.088 
.070 
1.15 
.025 
.029 
22 
T256 
.255 
.120 
.096 
1.50 
.042 
.063 
27 
T306 
.307 
.151 
.128 
.183 
.065 
.119 
36 
T376 
.375 
.205 
.128 
2.32 
.070 
.162 
30 
T446 
.440 
.229 
.159 
2.67 
.107 
.286 
42 
T506 
.500 
.303 
.190 
3.03 
.121 
.367 
46 
T686 
.690 
.370 
.190 
4.24 
.196 
.831 
47 
T806 
.795 
.495 
.250 
5.15 
.242 
1.246 
45 
T946 
.942 
.560 
.312 
6.00 
.385 
2.310 
70 
T1066 
1.060 
.570 
.437 
6.50 
.690 
4.485 
116 
T1306 
1.300 
.780 
.437 
8.29 
.730 
6.052 
96 
T1576 
1.570 
.950 
.570 
10.05 
1.140 
11.457 
115 
T1846 
1.840 
.950 
.710 
11.12 
2.040 
22.685 
195 
T2006 
2.000 
1.250 
.550 
12.97 
1.330 
17.250 
100 
T200A6 
2.000 
1.250 
1.000 
12.97 
2.240 
29.050 
180 
T2256 
2.250 
1.405 
.550 
14.56 
1.508 
21.956 
100 
MATERIAL 7  Permeability 9, Freq. Range
3 MHz to 35 MHz, Color  White

Core Number 
O.D.
(inches) 
I.D.
(inches) 
Hgt
(inches) 
l_{e
}(cm) 
A_{e
}(cm)^{2} 
V_{e
}(cm)^{3} 
A_{L} Value
µh/100 Turns 
T257 
.255 
.120 
.096 
1.50 
.042 
.063 
29 
T377 
.375 
.205 
.128 
2.32 
.070 
.162 
32 
T507 
.500 
.303 
.190 
3.03 
.121 
.367 
43 
T687 
.690 
.370 
.190 
4.24 
.196 
.831 
52 
MATERIAL 10 Permeability 6, Freq. Range
30 MHz to 100 MHz, Color  Black

Core Number 
O.D.
(inches) 
I.D.
(inches) 
Hgt
(inches) 
l_{e
}(cm) 
A_{e
}(cm)^{2} 
V_{e
}(cm)^{3} 
A_{L} Value
µh/100 Turns 
T1210 
.125 
.062 
.050 
.74 
.010 
.007 
12 
T1610 
.160 
.078 
.060 
.95 
.016 
.015 
13 
T2010 
.200 
.088 
.070 
1.15 
.025 
.029 
16 
T2510 
.255 
.120 
.096 
1.50 
.042 
.063 
19 
T3010 
.307 
.151 
.128 
.183 
.065 
.119 
25 
T3710 
.375 
.205 
.128 
2.32 
.070 
.162 
25 
T4410 
.440 
.229 
.159 
2.67 
.107 
.286 
33 
T5010 
.500 
.303 
.190 
3.03 
.121 
.367 
31 
T6810 
.690 
.370 
.190 
4.24 
.196 
.831 
32 
T8010 
.795 
.495 
.250 
5.15 
.242 
1.246 
32 
T9410 
.942 
.560 
.312 
6.00 
.385 
2.310 
58 
MATERIAL 12 Permeability 4, Freq. Range
50 MHz to 200 MHz, Color  Green & White

Core Number 
O.D.
(inches) 
I.D.
(inches) 
Hgt
(inches) 
l_{e
}(cm) 
A_{e
}(cm)^{2} 
V_{e
}(cm)^{3} 
A_{L} Value
µh/100 Turns 
T1212 
.125 
.062 
.050 
.74 
.010 
.007 
7.5 
T1612 
.160 
.078 
.060 
.95 
.016 
.015 
8.0 
T2012 
.200 
.088 
.070 
1.15 
.025 
.029 
10 
T2512 
.255 
.120 
.096 
1.50 
.042 
.063 
12.0 
T3012 
.307 
.151 
.128 
.183 
.065 
.119 
16.0 
T3712 
.375 
.205 
.128 
2.32 
.070 
.162 
15.0 
T4412 
.440 
.229 
.159 
2.67 
.107 
.286 
18.5 
T5012 
.500 
.303 
.190 
3.03 
.121 
.367 
18.0 
T6812 
.690 
.370 
.190 
4.24 
.196 
.831 
21.0 
T8012 
.795 
.495 
.250 
5.15 
.242 
1.246 
22.0 
T9412 
.942 
.560 
.312 
6.00 
.385 
2.310 
32.0 
MATERIAL 15 Permeability 25, Freq. Range
0.1 MHz to 2.0 MHz, Color  Red & White

Core Number 
O.D.
(inches) 
I.D.
(inches) 
Hgt
(inches) 
l_{e
}(cm) 
A_{e
}(cm)^{2} 
V_{e
}(cm)^{3} 
A_{L} Value
µh/100 Turns 
T1215 
.125 
.062 
.050 
.74 
.010 
.007 
50 
T1615 
.160 
.078 
.060 
.95 
.016 
.015 
55 
T2015 
.200 
.088 
.070 
1.15 
.025 
.029 
65 
T2515 
.255 
.120 
.096 
1.50 
.042 
.063 
85 
T3015 
.307 
.151 
.128 
.183 
.065 
.119 
93 
T3715 
.375 
.205 
.128 
2.32 
.070 
.162 
90 
T4415 
.440 
.229 
.159 
2.67 
.107 
.286 
160 
T5015 
.500 
.303 
.190 
3.03 
.121 
.367 
135 
T6815 
.690 
.370 
.190 
4.24 
.196 
.831 
180 
T8015 
.795 
.495 
.250 
5.15 
.242 
1.246 
170 
T9415 
.942 
.560 
.312 
6.00 
.385 
2.310 
200 
T10615 
1.060 
.570 
.437 
6.50 
.690 
4.485 
345 
T13015 
1.300 
.780 
.437 
8.29 
.730 
6.052 
250 
T15715 
1.570 
.950 
.570 
10.05 
1.140 
11.457 
360 
MATERIAL 17 Permeability 4, Freq. Range
20 MHz to 200 MHz, Color  Blue & Yellow

Core Number 
O.D.
(inches) 
I.D.
(inches) 
Hgt
(inches) 
l_{e
}(cm) 
A_{e
}(cm)^{2} 
V_{e
}(cm)^{3} 
A_{L} Value
µh/100 Turns 
T1217 
.125 
.062 
.050 
.74 
.010 
.007 
7.5 
T1617 
.160 
.078 
.060 
.95 
.016 
.015 
8.0 
T2017 
.200 
.088 
.070 
1.15 
.025 
.029 
10.0 
T2517 
.255 
.120 
.096 
1.50 
.042 
.063 
12.0 
T3017 
.307 
.151 
.128 
.183 
.065 
.119 
16.0 
T3717 
.375 
.205 
.128 
2.32 
.070 
.162 
15.0 
T4417 
.440 
.229 
.159 
2.67 
.107 
.286 
18.5 
T5017 
.500 
.303 
.190 
3.03 
.121 
.367 
18.0 
T6817 
.690 
.370 
.190 
4.24 
.196 
.831 
21.0 
T8017 
.795 
.495 
.250 
5.15 
.242 
1.246 
32.0 
T9017 
.942 
.560 
.312 
6.00 
.385 
2.310 
32.0 