[time-nuts] magnetic electronic components
time at radio.sent.com
Mon Jun 22 23:38:38 EDT 2015
This brings up a wide range of possible topics. You first need to
understand the physics, which is complex because magnetic fields
interact with matter in more interesting manners than electric fields,
due to spin and angular momentum.
* Magnetic moment (spin and orbital angular momentum):
* Magnetic field B:
* Magnetic field strength H:
* Magnetic hysteresis:
* Ferromagnetism: https://en.wikipedia.org/wiki/Ferromagnetism
* Ferrimagnetism: https://en.wikipedia.org/wiki/Ferrimagnetism
* Curie temperature: https://en.wikipedia.org/wiki/Curie_temperature
* Self inductance:
* Mutual inductance and transformers:
* Eddy current: https://en.wikipedia.org/wiki/Eddy_current
* Skin effect: https://en.wikipedia.org/wiki/Skin_effect
* Faraday effect: https://en.wikipedia.org/wiki/Faraday_effect Some of
these topics (such as skin effect) seem esoteric, but they are
crucial to understanding many common devices, such as why many large
AC power lines use multiple wires in parallel rather than one large
wire. Litz wire: https://en.wikipedia.org/wiki/Litz_wire
Because of mutual inductance, two circuits can be coupled to produce a
wide range of useful devices (transformers, baluns, etc.). Certain
materials (such as YIG spheres) can be used to produce magnetically
tuned filters which are commonly used in microwave devices.
There are many practical books on the use of certain magnetic devices,
such as ferrite cores. You can also find resources on design of
switching power supplies which discuss the magnetic materials involved.
Ferromagnetic Core Design & Application Handbook
Magnetics design for switching power supplies:
The practical applications for science are much more interesting than
the average person realizes. Of course, magnetic behavior combine with
electric behavior resulting in electromagnetism, leading to transmission
line theory and electromagnetic radiation. But that's more than you
asked for. :)
Bill Byrom N5BB
On Mon, Jun 22, 2015, at 06:56 PM, Bob kb8tq wrote:
> The problem with coils (inductors) is that they are indeed on the “other
> of the physics / electrical engineering divide. They are not unique in
> this way.
> Most components are dealt with to a “equivalent model” level and then
> in engineering.
> You have two choices:
> 1) Read the physics stuff
> 2) Go back far enough that the divide had not occurred ( <= 1950’s).
> Sorry about that ….
>> On Jun 22, 2015, at 2:02 PM, Attila Kinali <attila at kinali.ch> wrote:
>> I was looking up some stuff and realized (again) that I don't know
>> anything about how magnetic electronic components (inductors/solenoids,
>> transfomers, baluns, ferrite beads...) work. Yes, I can calculate
>> the inductance, I know how to get from the AL value to number of
>> windings. But I don't know anything about the practical issues
>> or where they come from. Unfortunatelly, this knowledge seems to
>> generally rare among EEs (at least everyone I asked in the last
>> couple of years) and books about it are either long out of print
>> (with no pdf available) or more geared towards the physics student.
>> So, does anyone have any recomendation where I could read up
>> on this? Books, pdfs, webpages,... anything.
>> Also something that covers more the application side, ie how to
>> use ferrite beads/toroids to build devices, would be appreciated.
>> Thanks in advance
>> Attila Kinali
>> I must not become metastable.
>> Metastability is the mind-killer.
>> Metastability is the little-death that brings total obliteration.
>> I will face my metastability.
>> I will permit it to pass over me and through me.
>> And when it has gone past I will turn the inner eye to see its path.
>> Where the metastability has gone there will be nothing. Only I will remain.
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