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Old June 17th 04, 08:30 PM
Gray Shockley
 
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On Wed, 16 Jun 2004 14:50:47 -0500, AC/DC wrote
(in article ) :

I am assuming that a microwave oven is a Faraday cage.


Often attributed to Abraham Lincoln:

question: How many legs does a dog have it we count the dog's
tail as a leg?
answer: Four. Caliing something by a name doesn't make it
necessarily so.

No, there is no Faraday cage inside a microwave oven anymore than
coax is constructed of an inner wire, then physical insulation,
then a Faraday cage, then the outer physical insulation.

A microwave oven has shielding. Hopefully, enough shielding that
it warms your coffee rather than you.

Since it keeps
the radiation trapped, bouncing around inside to heat up the food
instead of you. I am betting you would loose signal on a cell phone
completley if it were placed inside of a microwave with the door
closed. This should work even with the oven unplugged from the wall
outlet, which then would be ungrounded.


Seems likely. But you could do the same thing with a big hunk of
shielding from that coax we were using earlier.

The electric field inside a Faraday cage is zero, regardless of what
the outside is doing or is connected to.


Not necessarily at all. A properly constructed Faraday cage (and
they are simple and very easy to construct) has only the
electrical/electronic field of any device within that generate
something or atother.

But the reverse is also true.


The original wasn't true, either.

The charges that are built up from components inside of the Faraday
cage are trapped to bounce around like the radiation inside of a
microwave.


Do what? And to whom? And,
"uh, eh, what?!?" ---- interrorbang

There aren't any charges "built-up" inside a Faraday cage. It's
not a capacitor, it's a blocktor -- joke on name. All five sides
are tied together and well-grounded to dissipate the energy from
both outside and inside.

So that makes me think it needs to be grounded. On the
other hand, if the shell of a microwave is grounded. Then what keeps
the radiation inside from going to ground instead of bouncing around
and cooking your food?


The radiation of the klystron (or whatever is being used
nowadays) radiates outward from the klystron. It strikes the
coffee cup and permeates through to the coffee. It, then, follows
the path of least resistance to the ground (because the
definition of a ground is - yep, all that stuff, including that,
also because . . . And stuff. And so forth.).


I get the suspicious feeling (grin) that your "theory" abolishes
the possibility of so-called "radio waves" ever having any useful
purpose unless the xmtr and antenna aren't grounded.




Gray Shockley
--------------------------------------------------------
If you're aligning the first stage in a receiver and,
at the same time, someone is working on a
2kw jammer in the same area, a Faraday
Case could be an asset.