degauss function?
KIM
thanks
KIM
Thomas Rohricht
<j4i06.23004$Z33.2...@news0.telusplanet.net>:
>i have a MAG DX700T monitor and it has a Degauss function. what is it
>for?
>
Does anybody else get an uncomfortable feeling every time they degauss
their monitor while sitting directly in front of it? It's probably just
psychological but I could swear I feel waves of EM hurtling through my body
...
--
Thomas Rohricht - CO2 Creative
trohricht_(at)_co2creative_(dot)_com
Forward-thinking graphics and design
gosh...@my-deja.com
earth's natural magnetic field. The earth's magnetic field is always
changing, thus it has a constant influence on the monitor. In order to
reduce these effects every monitor has a degauss circuit that helps keep
the colors pure and the geometry correct.
There is a coil of wire that goes around the picture tube just under the
plastic near the front of the monitor. This is the degauss coil. When
the monitor is turned on it will automatically degauss itself by sending
a large current though this coil of wire. The degaussing circuit uses a
thermistor to taper off the degaussing current over a period of a few
seconds. Tapering the current off prevents the degaussing process from
actually creating a residual magnetic field in the metal parts of your
monitor instead of eliminating them.
Thomas, do you use a hair dryer, if so do you feel the waves from it?
Hair dryers like many common appliances in the home use coils of wire
with high electric currents.
For more information on using monitors and issues on health and safety
see the following links
http://www.csf.org.uk/csf/monitors/monitorsfaqs.htm
http://www.pc.ibm.com/ww/healthycomputing/ergodisp.html
Good Luck
Jim at http://www.monitorsdirect.com
Sent via Deja.com
http://www.deja.com/
GSV Three Minds in a Can
<s...@sig.file> writes
>kim...@REMOVETHIS.telus.net (KIM) wrote in
><j4i06.23004$Z33.2...@news0.telusplanet.net>:
>
>>i have a MAG DX700T monitor and it has a Degauss function. what is it
>>for?
>>
>
>Does anybody else get an uncomfortable feeling every time they degauss
>their monitor while sitting directly in front of it? It's probably just
>psychological but I could swear I feel waves of EM hurtling through my body
Just poke the switch with an 8' bamboo cane, from a safe distance, or
remember to wear your alumin(i)um foil suit. 8>.
--
GSV Three Minds in a Can
Thomas Rohricht
<cDIa7NAO...@quik.freeuk.net>:
>In article <901151FAFtrohr...@24.2.9.58>, Thomas Rohricht
>>
>>Does anybody else get an uncomfortable feeling every time they degauss
>>their monitor while sitting directly in front of it? It's probably just
>>psychological but I could swear I feel waves of EM hurtling through my
>>body
>
>Just poke the switch with an 8' bamboo cane, from a safe distance, or
>remember to wear your alumin(i)um foil suit. 8>.
My monitor didn't come with either.
GSV Three Minds in a Can
<s...@sig.file> writes
>G...@quik.freeuk.com (GSV Three Minds in a Can) wrote in
><cDIa7NAO...@quik.freeuk.net>:
>
>>In article <901151FAFtrohr...@24.2.9.58>, Thomas Rohricht
>>>
>>>Does anybody else get an uncomfortable feeling every time they degauss
>>>their monitor while sitting directly in front of it? It's probably just
>>>psychological but I could swear I feel waves of EM hurtling through my
>>>body
>>
>>Just poke the switch with an 8' bamboo cane, from a safe distance, or
>>remember to wear your alumin(i)um foil suit. 8>.
>
>My monitor didn't come with either.
For someone with the moniker 'CO2 Creative' that is a bit feeble Thomas!
Bamboo canes available at good garden centres, Foil suits can be
constructed from the stuff Turkey's wear in the oven, plus some sticky-
backed plastic.
Thomas Rohricht
Understood, but I've been deliberately holding off on the big ticket items
like bamboo poles and foil jocks because it's so close to Christmas. Long
ago I made it a rule not to buy myself any extra-special treats at this
time of year, because it gives such joy to my friends and family when
*they* can be the ones to put a nice hand-made lead-lined undergarment
under the tree.
Nothing says "happy holidays" like bamboo and tinfoil.
Khayman
diet-coke..
After several hours by the computer shooting up coke (the standard
cola-kind) the stomach started creating these horrible gases - so by
altering the frequency of the monitor the hacker's stomach responds to a
neural-central signal and releases a real-time streamed exhaust to the rear
of the hacking chair... This way the hacker wouldn't need to move his
behind to the left (or right), concentrate his muscles and release an
uncontrolled gas-pocket unto some unsuspecting other hacker...
The "degauss" actually saved the lives of quite a few chain-smoking hacker's
back in the 80's you know..
But then agian, there are some people who say that degauss has to do with
the de-magnetizing of the monitor picture tube, but that's just a tale IBM
came up with since they couldnt discuss the "de-gas" function at board
meetings without being "unmoral"...
"KIM" <kim...@REMOVETHIS.telus.net> skrev i meddelandet
news:j4i06.23004$Z33.2...@news0.telusplanet.net...
KIM
have made me even more confused lol
so...bascially, the degauss function is to eliminate EM charges within the
monitor itself? what's all this talk about degaussing the monitor from a
safe distance then?
KIM
GSV Three Minds in a Can
<kim...@REMOVETHIS.telus.net> writes
It's mostly a joke, however it is a fact that when you degauss (which
happens automatically at power on, with most monitors) you do generate a
big burst of EM radiation. I personally wouldn't worry about it, but
some folks might (the ones who wear tin hats to stop the Martian mind
control rays, in particular).
Hans Bergengren
"GSV Three Minds in a Can" <G...@quik.freeuk.com> wrote:
> It's mostly a joke, however it is a fact that when you degauss (which
> happens automatically at power on, with most monitors) you do generate a
> big burst of EM radiation.
Actually, it's not EM radiation, it's a magnetic field. And magnetism isn't
radiation at all...
Bye!
/HB.
GSV Three Minds in a Can
<fa...@swipnet.se> writes
Actually, actually it is an ELECTRO magnetic field, being derived from
the passage of lots of volts through a large coil, and it 'radiates'
quite nicely, since you can pick it up quite a way from the tube. I
agree it isn't 'radioactivity' type radiation.
It's just the same sort of stuff you get from living under a power line
(although I'd worry about the latter rather more than the occasional
degaussing of my CRT).
--
Hans Bergengren
"GSV Three Minds in a Can" <G...@quik.freeuk.com> wrote:
> Actually, actually it is an ELECTRO magnetic field
...Which pertains to the way the field was created, not the properties of
the field itself. Electro-magnetic radiation is carried by a wave/particle
energy quanta thingy called a photon (mainly made famous through Star Trek
and not physics books it would seem 8-), and have a particular
frequency/wave length. Magnetic fields do not have a natural frequency
(unless you actually make a device to create such a field of course, but
that's a bit like making a puppet on strings dance; it's not the puppet that
is dancing, it is the strings...) Electro-magnetism is undiscernable from
any other kind of magnetism, except for the fact it's created by an
electrical current running through a conductor...
> being derived from
> the passage of lots of volts through a large coil, and it 'radiates'
> quite nicely, since you can pick it up quite a way from the tube.
I suppose next you would like to call gravity a kind of radiation too, hm?
8-) It's the same thing; fields are fields; not radiation.
> It's just the same sort of stuff you get from living under a power line
Still not radiation, though.
Bye!
/HB.
PS: I agree it's likely quite harmless degaussing a CRT now and then. The
X-ray radiation dose one recieves from sitting in front of the tube for
hours on end is probably far more damaging.
GSV Three Minds in a Can
<fa...@swipnet.se> writes
>
>"GSV Three Minds in a Can" <G...@quik.freeuk.com> wrote:
>
>> Actually, actually it is an ELECTRO magnetic field
>
>...Which pertains to the way the field was created, not the properties of
>the field itself.
let me give you a bigger clue. The electromagnet needs to be turned on
at some point. When you do that the field changes. This radiates. In the
case of a degaussing coil, it is an AC electromagnet, so the field
changes continuously, by design (but the largest transient it when it is
turned on).
You should be able to detect the radiated EM with an oscilloscope and
coil antenna - it's probably not enough to foul up a transistor radio.
>I suppose next you would like to call gravity a kind of radiation too, hm?
>8-) It's the same thing; fields are fields; not radiation.
=fluctuating= fields are radiation. You can extract energy from them.
Nobody has managed, afaik, to fluctuate a gravitational field enough to
be detected yet.
>> It's just the same sort of stuff you get from living under a power line
>
>Still not radiation, though.
?? So how, exactly, does the energy get from the (50Hz, 180KV, three
phase - just incase you have DC power transmission in Sweden) power
lines into your car radio, as you drive underneath .. pixies? People
have actually stuck coils under power lines and (illegally) powered
their house for free. You can get (disconnected) fluorescent tubes to
light up, under some HV power lines. Still think there is no EM
radiation involved?
--
Bob Myers
debate....:-)
What a degauss coil produces is an alternating MAGNETIC
field. As was already pointed out, this is not the same thing
as "electromagnetic radiation", which requires (overly-
simplified) that the magnetic component of the field be
accompanied by a related electric field. (In the more modern
"quantum mechanical" perspective, this IS where we start
talking about photons and such, but let's not do that here
just yet, OK?) The fact that this magnetic field is (a) varying
or (b) created through the passage of electric current through
a coil of wire does NOT somehow make this into "EM
radiation".
Now, to get back to the original concern that brought up the
question in the first place: there HAVE been some concerns
expressed about low-frequency electric, magnetic, and EM
fields from CRT monitors; however, I must also immediately
point out that no concrete link between such fields and ANY
health concerns has ever been established. Still, numerous
standards have been established for the levels of these fields,
and practically all modern monitors comply with these standards.
The momentary magnetic field produced by the action of the
degauss coil is a permitted exception to the limits, just because
it IS of such very short duration. To sum up, I'm not going to
lose any sleep over the fields I'm exposed to when working
at my monitor.
And not that you should just take my word on any of this - there
are certainly numerous other sources around to look up if
anyone is really concerned about it - but I did spend a
reasonable chunk of my career doing EM qualifications on
various display products, so I think I can claim some familiarity
with the topic.
Bob M.
GSV Three Minds in a Can
<nomail...@address.invalid> writes
>OK, just to put my $0.02 in on the "is too!" "is not!"
>debate....:-)
>
>What a degauss coil produces is an alternating MAGNETIC
>field. As was already pointed out, this is not the same thing
>as "electromagnetic radiation", which requires (overly-
>simplified) that the magnetic component of the field be
>accompanied by a related electric field.
So we have a varying magnetic field, the variation in which propagate at
the speed of light, and which can induce current in a remote coil (cf
'transformer') but you're telling me that this isn't any form of
Electromagnetic radiation? It is just 'magnetic radiation' ?? Great
revolving Maxwells..
> (In the more modern
>"quantum mechanical" perspective, this IS where we start
>talking about photons and such, but let's not do that here
>just yet, OK?)
In fact not at all??
> The fact that this magnetic field is (a) varying
>or (b) created through the passage of electric current through
>a coil of wire does NOT somehow make this into "EM
>radiation".
The variations in the field propagate as waves, at the speed of light.
Per Maxwell, and Hertz, I thought that stuff was called EM Radiation?
Ok, so the kind generated from 50/60hz is low frequency, with
wavelengths in the 1000s of KM, but it's still EM Radiation, no?
>
>Now, to get back to the original concern that brought up the
>question in the first place: there HAVE been some concerns
>expressed about low-frequency electric, magnetic, and EM
>fields from CRT monitors; however, I must also immediately
>point out that no concrete link between such fields and ANY
>health concerns has ever been established. Still, numerous
>standards have been established for the levels of these fields,
>and practically all modern monitors comply with these standards.
>The momentary magnetic field produced by the action of the
>degauss coil is a permitted exception to the limits, just because
>it IS of such very short duration. To sum up, I'm not going to
>lose any sleep over the fields I'm exposed to when working
>at my monitor.
I don't think anyone is suggesting there is a problem (except maybe the
foil hat brigade).
see: http://vitatech.net/eng2.html for an explanation of the various
spectra of EM fields (aka EM radiation). CRTs and power lines are right
in there (under ELF - Extremely Low Frequency).
Hans Bergengren
"GSV Three Minds in a Can" <G...@quik.freeuk.com> wrote:
> let me give you a bigger clue. The electromagnet needs to be turned on
> at some point. When you do that the field changes. This radiates.
It's still not *radiation* in the sense one puts the word in normally.
Magnetism is a *field*, it's not radiation at all.
> You should be able to detect the radiated EM with an oscilloscope and
> coil antenna - it's probably not enough to foul up a transistor radio.
To pick up the magnetic field, you need something called a magnetometer I
believe. Magnetism isn't EM radiation. EM radiation belongs to the
electromagnetic spectrum which stretches through long-wave radio to
ultra-short wave X-rays in the other end with visible light in there towards
the shorter wavelenght end. Magnetism is an entirely different phenomena.
> >I suppose next you would like to call gravity a kind of radiation too,
hm?
> >8-) It's the same thing; fields are fields; not radiation.
> =fluctuating= fields are radiation.
Uh... No, not really. It's still a field even though it radiates. It's
comparable to a solid, homogenous body, where 'true' [EM] radiation is
discrete particles/waves.
> So how, exactly, does the energy get from the (50Hz, 180KV, three
> phase - just incase you have DC power transmission in Sweden)
We have AC, like just about every other country on this globe I would
imagine. DC current doesn't take well to transportation over long distances,
and our country is very long and narrow.
> Still think there is no EM
> radiation involved?
EM radiation is emitted from the disconnected flourescent tube you
mentioned, but the magnetic field created by the powerline doesn't have
anything to do with EM radiation. It's magnetism, EM radiation is energy
quantas/photons.
Bye!
/HB.
GSV Three Minds in a Can
<fa...@swipnet.se> writes
>
>"GSV Three Minds in a Can" <G...@quik.freeuk.com> wrote:
>
>> let me give you a bigger clue. The electromagnet needs to be turned on
>> at some point. When you do that the field changes. This radiates.
>
>It's still not *radiation* in the sense one puts the word in normally.
>Magnetism is a *field*, it's not radiation at all.
I suggest you look up 'ELF'. (and even sub-ELF).
see: http://vitatech.net/eng2.html
>To pick up the magnetic field, you need something called a magnetometer I
>believe. Magnetism isn't EM radiation. EM radiation belongs to the
>electromagnetic spectrum which stretches through long-wave radio
That's your problem, right there. EM radiation spectrum extends from
'just above' DC (a DC field would be associated with a photon of
infinite wavelength, and zero energy) all the way up past X rays
(presumably something funny happens when the wavelength gets down around
the Planck length?).
I assume you agree that if I wind the 50hz on my power line, of
degaussing coil, up to 1 Mhz, the resulting fluctuating field would be
EM radiation, since it is now in the AM radio part of the spectrum?? If
so, we just have a terminology disconnect.
>to
>ultra-short wave X-rays in the other end with visible light in there towards
>the shorter wavelenght end.
>Magnetism is an entirely different phenomena.
James Maxwell would be very disappointed to hear this (were he not
dead). istr he spent a lot of time proving magnetism and electricity
were irretrievably linked.
<snip>
>> So how, exactly, does the energy get from the (50Hz, 180KV, three
>> phase - just incase you have DC power transmission in Sweden)
>
>We have AC, like just about every other country on this globe I would
>imagine. DC current doesn't take well to transportation over long distances,
>and our country is very long and narrow.
Good, but you didn't answer the question. Energy can be extracted from a
varying magnetic/electric field, at a distance. You can harness the 50hz
field from a power line with a loop underneath. You can hear the 50hz
hum as you drive under one.
Now what is the carrier of energy from the coil, or power line, to the
receiver: you've got several choices - photons, electrons, neutrinos,
quarks, pixies, etc. (I don't know of any quantised units of magnetic
energy, but I guess you can propose one).
--
Bob Myers
"GSV Three Minds in a Can" <G...@quik.freeuk.com> wrote in message
news:JoVvhOAy...@quik.freeuk.net...
> So we have a varying magnetic field, the variation in which propagate at
> the speed of light, and which can induce current in a remote coil (cf
> 'transformer') but you're telling me that this isn't any form of
> Electromagnetic radiation? It is just 'magnetic radiation' ??
Exactly correct. It is NOT a form of electromagnetic radiation,
which specifically requires both a magnetic AND electric
field component. Consider the situation of a permanent
magnet mounted on a shaft, such that you can flip the thing
over (north-south-north-south-...and so forth). What will be
detected in any region of space around that revolving
magneting is a varying - and in fact, alternating - magnetic
field. It has absolutely no electric-field component, though,
and as such there is NO true EM radiation present. (You
CAN, of course, still extract electrical energy from it; what
I've just described is the basis for a very simple generator.)
Or did you think you could make a radio transmitter by
spinning a magnet quickly enough?
By the way, the example you cited - the transformer - should
have been a tip-off; a transformer is an example of a
purely magnetically-coupled device (at least in the ideal case);
there is no EM radiation or coupling going on, or required in
the classic ideal-transformer analysis. (Go look up "magnetic
circuit" in a basic circuits or field-theory text for more info.)
> The variations in the field propagate as waves, at the speed of light.
> Per Maxwell, and Hertz, I thought that stuff was called EM Radiation?
> Ok, so the kind generated from 50/60hz is low frequency, with
> wavelengths in the 1000s of KM, but it's still EM Radiation, no?
In a word, no, and Maxwell and Hertz don't have anything to
say about it. (What Hertz discovered, the so-called "Hertzian
waves", were EM radiation, but they're not what we're talking
about here.) You are correct in thinking that both magnetic
fields and electric fields are two different manifestations of
what is the same fundamental force (the electromagnetic
force, one of the four "fundamental" forces), but that still
doesn't make any varying magnetic field in to an EM wave.
Again, show the electric component, and you might have
an argument.
> see: http://vitatech.net/eng2.html for an explanation of the various
> spectra of EM fields (aka EM radiation). CRTs and power lines are right
> in there (under ELF - Extremely Low Frequency).
Sure - but the fact that you CAN generate true EM radiation
at this frequency/wavelength does NOT mean that that's
what a degauss coil is putting out. Oh, there might be a
tiny, trivial amount of true 60 Hz EM being made - but in the
practical, realistic sense of what's going on here, a degauss
coil is simply making a MAGNETIC field.
Bob M.
Bob Myers
"GSV Three Minds in a Can" <G...@quik.freeuk.com> wrote in message
news:mEnQPNA5...@quik.freeuk.net...
> I suggest you look up 'ELF'. (and even sub-ELF).
> see: http://vitatech.net/eng2.html
Oh, gawd. And I suggest you get your hands on a good
basic EM text. YES, ELF radiation exists; no one has
disputed that. But that doesn't make the output of a
degauss coil (or any other coil, for that matter)
"electromagnetic waves". Such a coil produces, as
its primary purpose, a varying magnetic field, and that's
it. Any true EM radiation is incidental and is of a
relatively small (utterly ignorable, in this context) magnitude.
> >To pick up the magnetic field, you need something called a magnetometer I
> >believe. Magnetism isn't EM radiation. EM radiation belongs to the
> >electromagnetic spectrum which stretches through long-wave radio
>
> That's your problem, right there. EM radiation spectrum extends from
> 'just above' DC (a DC field would be associated with a photon of
> infinite wavelength, and zero energy) all the way up past X rays
One more time, PLEASE stop thinking that something MUST
be "EM radiation" simply because EM CAN exist at the
frequency in question. I suppose you believe that that big
thing picking up cars at the junkyard operates through
"EM radiation", and not a magnetic field? If so, please
explain how the electric and magnetic field components
of that "radiation" are related, and the magnitudes of each.
> I assume you agree that if I wind the 50hz on my power line, of
> degaussing coil, up to 1 Mhz, the resulting fluctuating field would be
> EM radiation, since it is now in the AM radio part of the spectrum?? If
> so, we just have a terminology disconnect.
Nope; what you would have would still be primarily a
high-frequency AC magnetic field; the EM radiation from
such a monstrosity (good luck in getting much 1 MHz
current through a degauss coil in the first place) would
increase somewhat, but what you're describing is still
a LONG way from being an efficient EM radiator. While
you're perusing that EM text, go look up what a suitable
antenna for 1 MHz might be, as well. Another example -
do you believe that transformers work through
electromagnetic coupling, or purely magnetic? If the
former, then tell me how well EM waves travel through
ferrite cores, and are contained by them. If the latter,
then tell me how this situation would magically transform
from a situation of magnetic coupling to EM radiation by
the primary coil, if the core were to be removed.
> >Magnetism is an entirely different phenomena.
>
> James Maxwell would be very disappointed to hear this (were he not
> dead). istr he spent a lot of time proving magnetism and electricity
> were irretrievably linked.
In that, at least, you are correct; magnetic fields and true
EM radiation ARE related. However, with respect to your
continuing to drag Maxwell into it, let me quote another of
my favorite philosophers - Inigo Montoya: "Thees word
you are using - I do not theenk eet means what you
theenk it means!"
> Good, but you didn't answer the question. Energy can be extracted from a
> varying magnetic/electric field, at a distance. You can harness the 50hz
> field from a power line with a loop underneath. You can hear the 50hz
> hum as you drive under one.
Yes, and that's called "magnetic coupling".
> Now what is the carrier of energy from the coil, or power line, to the
> receiver: you've got several choices - photons, electrons, neutrinos,
> quarks, pixies, etc. (I don't know of any quantised units of magnetic
> energy, but I guess you can propose one).
So since you don't believe that a particle has been
named for the carrier of "magnetic energy", you are
therefore maintaining that magnetic fields don't
exist? THAT'S an interesting position....
I've said about all I'm going to on this topic; it has no doubt long
ago lost the interest of the mainstream comp.sys.ibm.pc.
hardware.video (sheesh, we GOTTA get a shorter name for this
group!) audience, and if you want to learn about fields rather
than simply argue, I see no need to write a fields text just
for you. There are certainly many good ones available.
Bob M.
GSV Three Minds in a Can
<nomail...@address.invalid> writes
>
>"GSV Three Minds in a Can" <G...@quik.freeuk.com> wrote in message
>news:mEnQPNA5...@quik.freeuk.net...
>
>> I suggest you look up 'ELF'. (and even sub-ELF).
>> see: http://vitatech.net/eng2.html
>
>Oh, gawd. And I suggest you get your hands on a good
>basic EM text. YES, ELF radiation exists; no one has
>disputed that. But that doesn't make the output of a
>degauss coil (or any other coil, for that matter)
>"electromagnetic waves". Such a coil produces, as
>its primary purpose, a varying magnetic field, and that's
>it. Any true EM radiation is incidental and is of a
>relatively small (utterly ignorable, in this context) magnitude.
I didn't say that all/the only/or even 'the major' output from a
degaussing coil was EM radiation, just that EM radiation was produced.
The coil is certainly not designed to be an optimum antenna (hopefully
the inverse), but none-the-less it is surely going to radiate. Ditto an
AC power line. Both are actually cited (on that web page) as sources of
ELF EMR.
Would you like to take a stab at quantifying 'relatively small' - i.e.
what factor of the power input comes out as radiated power, in your
opinion .. 10^-3, 10^-6 .. ?
>One more time, PLEASE stop thinking that something MUST
>be "EM radiation" simply because EM CAN exist at the
>frequency in question. I suppose you believe that that big
>thing picking up cars at the junkyard operates through
>"EM radiation", and not a magnetic field?
Nope, it's a great big electromagnet. However it still radiates EM
(unless it's DC), albeit (hopefully) rather feebly. My point, which I
apparently failed to make clear, is that it is (nearly? wholly?)
impossible to produce an AC electromagnetic field, or indeed push an AC
current along a wire, without radiating some EM radiation in the
process. We can have a big argument about how much, but we apparently
both believe it is insignificant enough that tinfoil vests and a Faraday
cage are not required.
>> I assume you agree that if I wind the 50hz on my power line, of
>> degaussing coil, up to 1 Mhz, the resulting fluctuating field would be
>> EM radiation, since it is now in the AM radio part of the spectrum?? If
>> so, we just have a terminology disconnect.
>
>Nope; what you would have would still be primarily a
>high-frequency AC magnetic field; the EM radiation from
>such a monstrosity (good luck in getting much 1 MHz
>current through a degauss coil in the first place) would
>increase somewhat, but what you're describing is still
>a LONG way from being an efficient EM radiator.
Yep, I'd be much better off with a centre feed dipole antenna. Luckily
the CRT designers omitted that.
>> >Magnetism is an entirely different phenomena.
>>
>> James Maxwell would be very disappointed to hear this (were he not
>> dead). istr he spent a lot of time proving magnetism and electricity
>> were irretrievably linked.
>
>In that, at least, you are correct; magnetic fields and true
>EM radiation ARE related.
(all you need is an in-phase electric field. Well, an in-phase component
will do).
>> Good, but you didn't answer the question. Energy can be extracted from a
>> varying magnetic/electric field, at a distance. You can harness the 50hz
>> field from a power line with a loop underneath. You can hear the 50hz
>> hum as you drive under one.
>
>Yes, and that's called "magnetic coupling".
>
Yes, a lot of it is magnetic coupling - energy being shunted from
magnetic to electric fields, however =some= of the energy coming off a
power line is also EM radiation.
You seem to think I don't believe in magnetic fields .. I assure you I
do. I just don't believe in electrically produced magnetic fields which
are so 'purer than pure' than they don't have any EM component attached.
--
GSV Three Minds in a Can
<nomail...@address.invalid> writes
<snip>
>Consider the situation of a permanent
>magnet mounted on a shaft, such that you can flip the thing
>over (north-south-north-south-...and so forth). What will be
>detected in any region of space around that revolving
>magneting is a varying - and in fact, alternating - magnetic
>field. It has absolutely no electric-field component, though,
>and as such there is NO true EM radiation present. (You
>CAN, of course, still extract electrical energy from it; what
>I've just described is the basis for a very simple generator.)
>Or did you think you could make a radio transmitter by
>spinning a magnet quickly enough?
That's an interesting question. Having thought about it a bit, nope I
don't think that would produce EM radiation, not even if you stopped
rotating it, and just oscillated it perpendicular to the N/S axis. Not
sure I know what would happen if you were doing it in some electron-rich
environment though.
However since I can generate EMR by oscillating a point charge in free
space, I imagine I could do the same if I oscillated a magnetic
=monopole= fast enough?? Of course I'd have to find one first.
<big snip>
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