Re: [loopantennas] ferrite question
- On 01/13/2013 04:17 PM, dannibou wrote:
> Hi to members of this group. I know it's a bit off topicThere are two basic core material categories. The powdered
> but it is related to antenna and preamp circuits. I own
> several ferrite rings that I could use to build antenna
> preamp but the problem is that I don't know what it's
> their permeability. I know that it's important in some
> circuit and I wonder if it exist a way to know the
> caracteristics of them. I would like to classify them
> separately for future project. Any ideas? Sorry if my
> english is not as good as I would have liked.
iron group (actually iron or one of several high
permeability alloys, like Sendust or moly Permalloy) or
ferrite (a solid ceramic material that has low conductivity
compared to metals and high permeability, compared to most
The powdered cores are often used in power supplies, for
circuits that need energy storage inductors, like DC filters
or flyback transformers (where energy is first stored in the
core and then released into the output). These cores are
often painted in solid colors, often with one side a second
color, to encode their material and permeability.
Unfortunately, there is no universal code used by all
manufacturers, so knowing the color, without knowing the
manufacturer only narrows the possibilities. Measuring the
inductance of a test winding is often needed to be sure of
the permeability. An inductance meter or bridge is very
helpful for this work.
These cores are made of metal powder clued together with a
filler and binding material and are usually light grey color
(for the higher permeability, mostly metal ones)to tan (for
the mostly filler, low permeability ones), under the paint.
Ferrite comes in two common flavors. Nickle zinc ferrite
(NiZn) is used for most high frequency applications. It has
medium permeability (tens to hundreds), very high
resistivity (usually measures off scale high, if touched
with ohm meter probes) and has less flux capability than the
lower frequency materials. The lower frequency and power
materials are mostly Magnesium zinc ferrite (MnZn), and
generally have permeability ranging from hundreds to tens of
thousands. They are also a lot more conductive, with
conductivity generally lower, the higher the permeability.
You may get an ohm reading of thousands to hundreds of ohms
if you touch them with ohm meter probes.
All ferrites are black to dark grey and break like glass.
They can be used for transformers in ungapped forms,
including two piece parts that have polished mating
surfaces, or for energy storage and linear inductors, if a
gap is made between mating halves in the magnetic path.
Hi group. I have some ferrite of different size and color. I know that some are better for low frequency and other for high frequency. I would like to know how to identify them. Anyone know on how I can do this? Thanks
Here is a link to a core calculator application: http://www.dl5swb.de/html/mini_ring_core_calculator.htm
Go to the Iron Powder Torrid TAB. Then select the Material Button (right of the Core Size (i.e. T50). As you change the Core Material the applicable frequency band will show to the right in the Frequency Range box. Also the color code will change according the to Core Material, and at some point the color code will go from a single color to a dual color band.. You'll also get more information about your core with this app. (Note: For transmitter applications Ferrite Core are preferred. Iron Powder are OK for receive only applications, IMHO).
I added a link fir the mini Core Calculator app in the Links folder under the ferrites sub folder. Tab to the Iron Powder Torrid menu, and then select different Core Materials. This will provide you with the different color codes and Frequency Ranges.
- the colors are indexed and the data is proably on the mfrs. webpage
On Sat, Jan 11, 2014 5:35 PM EST dannibou@... wrote:
>Hi group. I have some ferrite of different size and color. I know that some are better for low frequency and other for high frequency. I would like to know how to identify them. Anyone know on how I can do this? Thanks
- See if one these sites help you:
73 Dave - AC2GL
I think this chart could be usefull.
the file is uploaded in the "files" section of the group.= caractéristiques tores ferrite xxxx .pdf
- Hi Danny,
i uploaded a file where some features of toroid ferrites are written.
the name is "caracteristiques tores ferrite_hftoxxxx.pdf.
I use it frequently.
- You cannot link to a file in that way, Yahoogroups provides a temporary link that only works for 20 minutes at most.
This is a message for all: Please do NOT use high ASCII characters in file names. I cannot make a link to the file now, and I am also unable to change the name or delete it so I can reupload after renaming.
I did finally find a workaround.
In future, please post files with names in English so as to avoid all high ASCII characters, and if it is a file on a website, please post a link rather than uploading it. We have only 100MB of file space. I just had to spend a lot of time cleaning out the Files area on another list.
Here is the company that the PDF came from:
Steve Greenfield AE7HD
your friendly but sometimes grumpy neighborhood moderator
--- In email@example.com, <grandbill59@...> wrote:
> I think this chart could be usefull.
> the file is uploaded in the "files" section of the group.= caractÃ©ristiques tores ferrite xxxx .pdf
- Now -that- is the way to do it. A link does not take up space, and it is available in the Links section for future use.
Steve Greenfield AE7HD
--- In firstname.lastname@example.org, <kc9q@...> wrote:
> I added a link fir the mini Core Calculator app in the Links folder under the ferrites sub folder. Tab to the Iron Powder Torrid menu, and then select different Core Materials. This will provide you with the different color codes and Frequency Ranges.
> Mike, KC9Q