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Sci.Electronics.Basics -> Ferrite Transformer ?
There are 4 messages in this thread.
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Author: mowhoong@hotmail.comDate: 09:54 21-03-07
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Some hobby project uses E or Round type of ferrite transformer which
are found in the HV driver
circuit. As this is uncommon or a standard type item, i like to know
how to self made one,
i don't understand why the primary and secondary winding use different
wire size ? and how to select the size or shap of the ferrite core for
optimal result ?Could any person help me in this.
Thanks in advance.
Regards
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Author: Rich GriseDate: 15:14 21-03-07
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On Wed, 21 Mar 2007 06:54:53 -0700, mowhoong@hotmail.com wrote:
> Some hobby project uses E or Round type of ferrite transformer which are
> found in the HV driver
> circuit. As this is uncommon or a standard type item, i like to know how
> to self made one,
This would be a horrendously challenging project for a newbie. Your best
bet would be to find one that you can sacrifice, and dissect it, to see
how it's done - this would also yield a core that you know will work at
the frequency of interest.
> i don't understand why the primary and secondary winding use different
> wire size ?
Different current-carrying capability.
> and how to select the size or shap of the ferrite core for
> optimal result ?
This is a whole field of study; even some experts don't know the black
magic involved here.
> Could any person help me in this. Thanks in advance.
Your best bet would be to go to a library and look for books on
transformer design, or maybe google for something similar. I don't know
if anyone around here would be willing to take on such a big task as
teaching you about ferrites and such, over USENET.
If you're seriously interested in it, signing up for a formal school
class would be the way to go.
Good Luck!
Rich
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Author: Anthony FremontDate: 15:21 21-03-07
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mowhoong@hotmail.com wrote:
> Some hobby project uses E or Round type of ferrite transformer which
> are found in the HV driver
> circuit. As this is uncommon or a standard type item, i like to know
> how to self made one,
It would be helpful if you better described the particular application.
These types of transformers are used from audio frequencies thru several
hundred MHz.
I don't know what you mean by "round". If you mean torroidal (do-nut shape)
then yes they are quite common. You may have to look harder for bars of the
material, but I don't really know that for sure. The secret to these things
is the composition of the material making them up. They may all look the
same, but the materials making them up vary quite a bit. Usually iron
powder and other magnetic metals are combined with ceramics in a proprietary
mix depending upon the application. Some materials enhance the inductance
very little, while some have tremendous effect. Again in RF applications,
this makes it possible to create coils for low frequency HF and not have to
use hundreds or even thousands of turns of wire. Some core materials have
so much inductance that they are pretty much only good for making RF chokes,
like you see on monitor cables etc...
> i don't understand why the primary and secondary winding use different
> wire size ?
It may be for current capacity reasons or space reasons. In RF applications
transformers are typically wound with the largest wire that will fit the
core to keep resistance to a minimum. This enhances the Q factor of the
coil and also reduces self heating. I'm sure there are probably other
reasons as well.
> and how to select the size or shap of the ferrite core for
> optimal result ?Could any person help me in this.
www.amidoncorp.com would be a good place to start.
Do-nut shaped cores are nice because they are "self shielding". This is
nice in RF applications because it keeps the signals where they belong
better.
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Author: EeyoreDate: 17:36 21-03-07
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"mowhoong@hotmail.com" wrote:
> Some hobby project uses E or Round type of ferrite transformer which
> are found in the HV driver
> circuit. As this is uncommon or a standard type item, i like to know
> how to self made one,
> i don't understand why the primary and secondary winding use different
> wire size ?
Because the size of the wire is related to the current. If it's a step-up
transformer for example, the secondary current is lower than the primary
current.
> and how to select the size or shap of the ferrite core for
> optimal result ?Could any person help me in this.
Learning transformer design is not a trivial (easy) task ! Some aspects of it
are quite straighforward but the detail is complicated.
Graham
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