chip swelling up and getting fried

[Ed Price]

"Rich Webb" <bbew.ar@mapson.nozirev.ten> wrote in message
news:46qdl0det9etq6864tgfk3dejg1uuqp6dq@4ax.com...

On Sun, 26 Sep 2004 03:48:08 -0700, "Ed Price" <edprice@cox.net> wrote:

Radio Shack used to be (maybe 30 years ago) an intriguing place to browse
and buy project parts. But for whatever reason, the selection and quality
of
discrete components has plummeted to the joke level. It was bad 10 years
ago, and it's even worse now.

My proof? Well, I can go into any store in the San Diego region, and get
the
same level of cheap parts. From what I hear on Usenet, this is typical
everywhere else. You could refute my experience, if you could cite a Radio
Shack that sells RG-214 coax, type N coax fittings, or switches that have
tin-plated terminals and a good "feel."

I don't have a citation/link (it's been several weeks since I read it)
but a recent industry rag had an article commenting that Radio Shack
might be returning at least partway to its roots. They apparently had a
"D'Oh!" moment and realized that there's no possible way to compete with
the warehouse retailers for the big ticket items. A typical RS has less
total shelf space than in just the notebook PC aisle at CompUSA.

On the other hand, a customer driving to CompUSA (or fill-in-the-blank)
probably passes at least a couple RS stores en route. So they're looking
to capture the "I need a ..." market for smaller items and piece parts.

I wish them luck. It is, perhaps, a sign of uber-geek sophistication to
dump on Radio Shack. But, even in the days of on-line ordering and
overnight delivery, it's pretty handy to be able to walk a couple of
blocks to the local RS and pick up a spool of wire-wrap wire.

--
Rich Webb Norfolk, VA

Not dumping on them, it's more like wondering how an old friend went over to
the dark side. RS just might have some wire-wrap wire. Do you think they
also have wrapping tools, suitable DIP sockets, switches with WW compatible
terminals, and maybe even an IC or two? Analog & logic stuff is not mutually
incompatible with RF, but I just notice the RS lack of RF components more
acutely.

Thus far, based on my last visit of a week ago, there's no evidence of any
new emphasis on component selection or quality. Fortunately for me, I have a
nearby Gateway, and a couple of big surplus stores too. Each has their
strengths, and I try my best to keep them all profitable. NAPA too! <g>

Ed
wb6wsn

 

[Repeating Rifle]

in article cj8eqs$9kd$0@pita.alt.net, Checkmate at LunaticFringe@The.Edge
wrote on 9/27/04 12:15 AM:

I think Heisenberg first developed that theory, but I'm not certain.

Planck introduce the concept of a quantum of energy in order to explain the
spectral distribution of black body radiation. Einstein and others were able
to extend the concept to explain specific heat and photoemission. Bohr first
applied it to atomic physics. Heisenberg developed the first modern theory
of quantum mechanics. Shrödinger formulated a wave equation that was much
more familiar to physicists of the day. The big surprise was that the
Schrödinger formulation gave identical results to that of Heisenberg's in
spite of appearing to be very different. The Schrödinger formulation was
much easier for making calculations while the Heisenberg formulation was
better suited to understanding essence of what quantum physics was all
about.

Bill

 

In alt.engineering.electrical John <John@john.com> wrote:
|
|>
|> Take two electrons, separated in space, stationary relative to some
|> observer. There's an electric field, obviously, but no magnetic field.
|> Now take another observer moving perpendicularly to the line joining the
|> electrons. This observe sees the electrons in motion. Electrons in
|> motion are an electric current, and an electric current produces a
|> magnetic field, so for that observer there is a magnetic field present.
|>
|> So one observer finds a magnetic field present where another observer
|> finds none. The notion that a magnetic field has a concrete existence is
|> clearly problematic. This paradox doesn't appear in the theory itself,
|> because it simply tells you what will happen (or more exactly, what your
|> measurements will show). It doesn't say anything about what is "really"
|> there.
|>
| This is all a bit over my head, but presumably the first observer (the one
| who doesn't see the magnetic field because it doesn't exist for him) sees
| something else; whatever the second observer sees as a magnetic field
| manifests itself somehow for the first observer? Don't conservation laws
| say that elements might vary, but the total sum must be the same?
| Probably not...

If there is motion between the observer and the electrons, the observer
might THINK he sees a magnetic field. But is it really there? That lies
in the ability to observe. How do you tell if a magnetic field is there
or not? You measure it by seeing how it acts on something. One way is
with a coil and ampmeter. But now that's electrons again. The net effect
is that something which is electrically changed has ultimately caused an
electrical current where movement is involved.

On the other hand, how do we know there is an electron there? Maybe it
only looks like it because that would explain a magnetic field, which is
what we are measuring. Maybe what we sense as an electric/static charge
is really a sensation of a magnetic current because we have to move in
some way to know there is a charge and where it is.

One cannot be without the other, but the real question is whether there
are really two things or not. I suggest that the answer is that what is
really there is one thing that simply is characterizsed both ways.

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

 

In alt.engineering.electrical CWatters <colin.watters@pandorabox.be> wrote:

| It isn't really composed of anything. It's a region in which a magnetic
| force can be detected. Ever seen a police car on the motorway? Everyone
| within 100 yards drives exactly at the speed limit. the police call this a
| bubble or zone of legality. The zone isn't composed of anythig but you can
| "feel the force".

It is composed of something called "fear".

--
-----------------------------------------------------------------------------
| Phil Howard KA9WGN | http://linuxhomepage.com/ http://ham.org/ |
| (first name) at ipal.net | http://phil.ipal.org/ http://ka9wgn.ham.org/ |
-----------------------------------------------------------------------------

 

[No Spam]

Repeating Rifle wrote:

in article cj8eqs$9kd$0@pita.alt.net, Checkmate at LunaticFringe@The.Edge
wrote on 9/27/04 12:15 AM:


I think Heisenberg first developed that theory, but I'm not certain.


Planck introduce the concept of a quantum of energy in order to explain the
spectral distribution of black body radiation. Einstein and others were able
to extend the concept to explain specific heat and photoemission. Bohr first
applied it to atomic physics. Heisenberg developed the first modern theory
of quantum mechanics. Shrödinger formulated a wave equation that was much
more familiar to physicists of the day. The big surprise was that the
Schrödinger formulation gave identical results to that of Heisenberg's in
spite of appearing to be very different. The Schrödinger formulation was
much easier for making calculations while the Heisenberg formulation was
better suited to understanding essence of what quantum physics was all
about.

Bill

And I thought Checkmate was being funny. ;-)

 

[Clint Sharp]

In message <cj9voq11lop@news2.newsguy.com>, phil-news-nospam@ipal.net
writes

In alt.engineering.electrical CWatters <colin.watters@pandorabox.be> wrote:

| It isn't really composed of anything. It's a region in which a magnetic
| force can be detected. Ever seen a police car on the motorway? Everyone
| within 100 yards drives exactly at the speed limit. the police call this a
| bubble or zone of legality. The zone isn't composed of anythig but you can
| "feel the force".

It is composed of something called "fear".

Sod that, I overtake the buggers. Never been pulled yet.

--
Clint Sharp

 

[CWatters]

"John (that Alaska guy)" <munged@purposely.net> wrote in message
news:4158E61C.4000904@purposely.net...

I don't want to bore holes in my house to put a cable TV outlet into
another room. Does anyone know of a low power transmitter/receiver
combination which will run on house power, which will function as a
"wireless cable" and for which I don't need some sort of license?

I know it's not exactly what you want but...

There are lots of products around that will transmit composite video (eg
leave the cable TV box where it is and just move the TV). They also send the
IR handset commands back the other way so you can control the cable TV box
from the remote location.

 

[E. Rosten]

Repeating Rifle wrote:

in article 4157DE09.1070909@my.sig, E. Rosten at look@my.sig wrote on
9/27/04 2:31 AM:


Shear stress can always be seperated out: you can represent any
combination of shear and tensile stress as pure tensile stress (google
for Mohr's Circle).

The Mohr's Circle operation is just a graphical way of diagonalizing the
stress matrix (well, it only works in 2D where the tensor is of rank 2).


Mohr's circle is a tensor on the cheap.

More like symmetric eigen decomposition done graphically. It just
happens that the matrix it operates on is a 2D stress tensor. But you
can still diagonalize it (ie represent shear as tension only).

In a sense, it was developed for
engineers who were not formally trained in tensors or their matrix
representations. The days when that was necessary, I hope, are over.

Your hopes may be elevated, sadly. Though I'm not sure.

Another crutch for tensors was developed under the name of *dyadics*.

They also are for rank 2 tensors aren't they?

-Ed

--
(You can't go wrong with psycho-rats.) (er258)(@)(eng.cam)(.ac.uk)

/d{def}def/f{/Times findfont s scalefont setfont}d/s{10}d/r{roll}d f 5/m
{moveto}d -1 r 230 350 m 0 1 179{1 index show 88 rotate 4 mul 0 rmoveto}
for /s 15 d f pop 240 420 m 0 1 3 { 4 2 1 r sub -1 r show } for showpage

 

[Repeating Rifle]

in article p_c6d.642262$Gx4.586918@bgtnsc04-news.ops.worldnet.att.net, Tom
Del Rosso at ng01@att.net.invalid wrote on 9/28/04 5:41 AM:

"Kevin Kilzer" <kkilzer.remove.this@mindspring.com> wrote in message
news:drvel0p49rt7vhp64ieosgsarumo7ghsc8@4ax.com

contribution was to show that a magnetic field is created as an
electric field changes, and an electric field is created as a magnetic
field changes.

Isn't it assymetrical, with a constant current producing a constant
magnetic field?


It is only assymmetrical because there are no magnetic charges. Magnetic

charge does not appear Maxwell's equations. The symmetries or lack of them
show up more strongly in the four-vector relativistic formulations.

Bill

 

[Roy McCammon]

tsp wrote:

Can somebody tell me why the lumped element model breaks down when
actual circuit impedances are very low,

I've never heard that.

or when the length of the wire approaches the
wavelength of the circuit's operating frequency?

Maxwell's equations are operative at all lengths
(ignoring qm). The question that really needs
to be answered is why to lumped models work
at all.




--
local optimization seldom leads to global optimization

my e-mail address is: <my first name> <my last name> AT mmm DOT com

 

[Nate Nagel]

Bob Ward wrote:

On Fri, 24 Sep 2004 17:49:09 GMT, Don Bruder <dakidd@sonic.net> wrote:


Radio Shack:
You've got questions, we've got blank stares.

Despite being something of a cliche, it's dead-on accurate in the huge
majority of RS stores.



Since you are making this statement as some sort of authoritative
comment, are we to assume that you have personally visiterd over 3500
stores (more than half would be a bare majority - we'll give you the
benefit of the doubt) in doing the research that leads you to this
conclusion?

Name them.

Have you ever visited a RS store where the counter help actually knows
anything about anything other than the CD players out front? I think I
may have, once, but I'm not sure. Most of the time I can find what I'm
looking for (or determine they don't have it) faster than any employee.

I suspect the "parts" section of RS is much like the little bins of
metric fasteners in the "big box" hardware stores - they're stocked
once, when the store opens, and never looked at again.

nate

--
replace "fly" with "com" to reply.
http://home.comcast.net/~njnagel