[RFI] Toroid Type?

David G. Henderson David G. Henderson" <daveh@erie.net
Sat, 25 Sep 1999 18:02:30 -0400


On 25 Sep 99, at 15:34, Larry Burke WI5A <lburke@wt.net> wrote:

> I thought I used to have a color code guide for
> one of the more popular manufacturers, but don't seem to afterall. Can
> anyone tell me what material this might be?
> 
> Larry WI5A

Here you go.  From the ARRL Handbook.  Save this to a file. Massage 
the tabs to get things to line up.  Print out in landscape format on 
your printer.  

Magnetic Properties Iron Powder Cores
Mix	Color	Material					Temp	f (MHz)	Notes
 				stability		
 				(ppm/C)		
 						
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 lower frequencies
15	Red/white		Carbonyl GS6	25	190	0.10 - 2	Excellent stability, good Q
 1	Blue			Carbonyl C		20	280	0.50 - 5		Similar to Mix-3, but better stability
 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 temperature  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 temperature stability
17	Blue/yellow		Carbonyl	 	4	 50	40 - 180 		Similar to Mix-12, better temperature stability, Q drops about 10% above 50 MHz, 20% above 100 MHz


0	Tan			phenolic	 	1	 0	100 - 300 		Inductance may vary greatly with winding technique
73, Dave, N3EOY
mailto:daveh@erie.net

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