Toroids: Powdered Iron

Use the table below to calculate inductance and number of turns per the following formulas.

Where:

L = inductance in µH
A_L = µH per 100 turns
N = number of full turns

Iron Powder Magnetic Core Properties
Mix	Color	Material	μ	Temp Stability (ppm/°C)	f (MHz)	Uses
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

Iron Powder Magnetic Core Dimensions
Size	Color	Dimensions (in)
Size	Color	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