Toroids: Powdered Iron
Use the table below to
calculate inductance and number of turns per the following formulas.
Where:
L = inductance in µH L = µH per 100 turns
Size 26 3 15 1 2 7 6 10 12 17 0
T-12
n/a
60
50
48
20
18
17
12
7.5
7.5
3.0
T-16
145
61
55
44
22
n/a
19
13
8.0
8.0
3.0
T-20
180
76
55
52
27
24
22
16
10
10
3.5
T-25
235
100
85
70
34
29
27
19
12
12
4.5
T-30
325
140
93
85
43
37
36
25
16
16
6.0
T-37
275
120
90
80
40
32
30
25
15
15
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
18
6.4
T-68
420
195
180
115
57
52
47
32
21
21
7.5
T-80
450
180
170
115
55
50
45
32
22
22
8.5
T-94
590
248
200
160
84
n/a
70
58
32
n/a
10.6
T-106
900
450
345
325
135
133
116
n/a
n/a
n/a
19
T-130
785
3350
250
200
110
103
96
n/a
n/a
n/a
15
T-157
870
420
360
320
140
n/a
115
n/a
n/a
n/a
n/a
T-184
1640
720
n/a
500
240
n/a
195
n/a
n/a
n/a
n/a
T-200
895
425
n/a
250
120
105
100
n/a
n/a
n/a
n/a
26
Yellow/White
Hydrogen Reduced
75
825
DC -1
EMI filters, DC chokes
3
Gray
Carbonyl HP
35
370
0.05 - 0.50
Exc. stability, good Q at low freq.
15
Red/White
Carbonyl GS6
25
190
0.10 - 2
Exc. stability, good Q
1
Blue
Carbonyl C
20
280
0.50 - 5
Exc. stability, good Q at low freq.
2
Red
Carbonyl E
10
95
2 -30
High Q
7
White
Carbonyl TH
9
30
3 - 35
Similar to mix 2 and mix 6, exc. temp stability
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
Blue/Yellow
Carbonyl
4
50
40 - 180
Similar to mix 12, better temp. stability, Q drops about 10% above 50 MHz, 20% above 100 MHz
0
Tan
Phenolic
1
0
100 - 300
L varies greatly with winding technique
Size Color Dimensions (in)
O.D. I.D. Height
T-200-2
Red
2.00
1.25
0.55
T-94-2
Red
0.94
0.56
0.31
T-80-2
Red
0.80
0.50
0.25
T-68-2
Red
0.68
0.37
0.19
T-50-2
Red
0.50
0.30
0.19
T-37-2
Red
0.37
0.21
0.12
T-25-2
Red
0.25
0.12
0.09
T-12-2
Red
0.125
0.06
0.05
T-50-10
Black
0.50
0.30
0.19
T-37-10
Black
0.37
0.21
0.12
T-25-10
Black
0.25
0.12
0.09
T-12-10
Black
0.125
0.06
0.05
T-94-9
Yellow
0.94
0.56
0.31
T-80-6
Yellow
0.80
0.50
0.25
T-68-6
Yellow
0.68
0.37
0.19
T-50-6
Yellow
0.50
0.30
0.19
T-26-6
Yellow
0.25
0.12
0.09
T-12-6
Yellow
0.125
0.06
0.05
Kirt Blattenberger ,
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