On Fri, 26 Dec 2003 17:05:15 GMT, Dave Shrader
wrote:

Richard Clark wrote:

SNIP

The ONLY advance we can claim in the last half century, is that no
power is lost to lighting up filaments in transistors.



Oh Boy!! 50 years of hamming, 43 years of engineering, 40 years of
marriage, 15 years of ministry, and 3+ years of retirement and NOW I
FINALLY FIND OUT WHY TRANSISTOR DON'T LIGHT UP!!!

I better hold on to my 3-500 Amplifier so I can demonstrated a ham
station to the neighborhood kids ... lots of light!

OK Fellows,

Such lackluster response to this single comment!

Lots of light Dave? Really? Then obviously you were not driving hard
enough!

When I broke into this business/hobby back then, I worked for a Ham in
his TV repair business. One of the notable experiences was watching
his final's plates glowing a cheery ruby red and the surrounding
envelope filled with a violet light. The Amp may have not been
"optimized" nor was the output free of spurs; the line voltage sagged
a bit in the effort (another tribute to the Thevenin model); but no
one was analyzing the situation. We didn't need a thermometer to
prove where the calories in plate resistance were.

It gives me the grins when these kind of debates about Thevenin
Resistors ignores the obvious. Some folks demand a carbon composition
resistor to fulfill their imaginings. :-)

73's
Richard Clark, KB7QHC

Is it possible to have a 1:1 SWR?
--------------------------
Yes!

73 de Jack, K9CUN

"JDer8745" wrote in message
...
Is it possible to have a 1:1 SWR?
--------------------------
Yes!

73 de Jack, K9CUN


Agreed! I get it all the time with my dummy load.

Ed
WB6WSN

Dear Rich, your patience is admirable.

The world of electrical engineering would have been a far more more
understandable place if Thevenin and other trivial theorem inventors of his
ilk had never existed. As things are, the only purpose served by such
superfluous statements of the bleeding obvious is to assist university
professors and Ph.D's in justifying their grants and salaries.


But people must be allowed to make livings and reputations in the best way
they can even if, inadvertently, they turn out to be a handicap. The human
race is now so wealthy the economy can well afford them. ;o)


By the way, what DID Thevenin say? I don't recall ever having knew. Have
I never progressed beyond V = I*R ?
----
Reg

Reg Edwards wrote:
By the way, what DID Thevenin say?

Here's what Ramo and Whinnery said about Thevenin: "It must be emphasized,
as in any Thevenin equivalent circuit, that the equivalent circuit was
derived to tell what happens in the load under different load conditions,
and significance cannot be automatically attached to a calculation of
power loss in the internal impedance of the equivalent circuit."
--
73, Cecil http://www.qsl.net/w5dxp



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On Mon, 29 Dec 2003 13:38:53 +0000 (UTC), "Reg Edwards"
wrote:

The world of electrical engineering would have been a far more more
understandable place if Thevenin and other trivial theorem inventors of his
ilk had never existed.

Hi Reg,

Your observation reminds me of Arthur Dent's outrage with Ford
Prefect's considered opinion of the importance of Earth within the
scheme of the Universe:
"Mostly harmless"

73's and remember where your towel is,
Richard Clark, KB7QHC

Someone sed:

"The world of electrical engineering would have been a far more more
understandable place if Thevenin and other trivial theorem inventors of his ilk
had never existed."
===========================

Spoken by a person who is extremely ignorant of what he writes about.

It is because of Thevenin's theorem that complicated circuits can be reduced to
the equivalent circuit consisting of only two components: a voltage source and
an impedance. This is a powerful tool. If I didn't know it, I'd learn it.

73 de Jack, K9CUN

"The world of electrical engineering would have been a far more more
understandable place if Thevenin and other trivial theorem inventors of
his ilk
had never existed."
===========================

Spoken by a person who is extremely ignorant of what he writes about.

It is because of Thevenin's theorem that complicated circuits can be
reduced to
the equivalent circuit consisting of only two components: a voltage source
and
an impedance. This is a powerful tool. If I didn't know it, I'd learn
it.

73 de Jack, K9CUN

============================

For heaven's sake Jack, is THAT all what it's about ?


How come 95% of the contributors to this newsgroup come to blows with each
other about the manner of its application? Apparently Thevenin is a severe
educational handicap rather than an asset. But perhaps newsgroup Guru's at
loggerheads with each other are not representative of the engineering
fraternity in general.


Normal sixteen year-old students, with the right teacher, grasp the idea
immediately without they or their teacher ever having heard of Thevenin. It
can then be forgotten. It's so bleeding obvious!


As John Cleese implies - students, even at that tender age, should be
endowed with a first-class honors degree, including cap and gown, in the
venerable practice of the ancient Babylonians, Hittites and Egyptians in
stating the obvious.


In this more recent age, can we soon expect a graduate of that rat-infested
campus of the Rio de Janerio sewers to announce in a blaze of glory that "A
complicated circuit is reduceable to an equivalent circuit consisting merely
of two components: a current source and an impedance."? Let's hope his
name will be pronounceable.
----
Yours, Reg. ;o)

Reg, G4FGQ wrote:
"A complicated circuit is reduceable to an equivalent circuit consisting
merely of two components: a current source and an impedance."? "Let`s
hope his name will be pronounceable."

True. Does the name "Norton", as in Norton`s Theorem, seem
pronounceable? Reg`s assertion is indubitable.

In a linear circuit, any generator of electric power may be considered
equivalent, at specified frequency, to a current generator whose current
is equal to the short-circuit current in shunt with an admittance whose
magnitude is equal to that when the generator is inactive and there is
no load connected to it, says Henney in his "Radio Engineering
Handbook".

The Thevenin`s Theorem impedance is the open-circuit voltage divided by
the short-circuit current.

Terman says on page 95 of his 1937 2nd edition of "Radio Engineering":

"According to Thevenin`s theorem, any linear network containing one or
more sources of voltage and having two terminals behaves, insofar as a
load impedance connected across the terminals is concerned, as though
the network and its generators were equivalent to a simple generator
having an internal impedance Z and a generator voltage E, where E is the
voltage that appears when no load is connected and Z is the impedance
that is measured between the terminals when all sources of voltage in
the network are short-circuited."

We have argued about the linearity required to make the Thevenin
equivalent valid. Terman says that linearity is the only limitation to
validity.

Best regards, Richard Harrison, KB5WZI

Reg, G4FGQ wrote:
"---students, even at that tender age, should be endowed with a
first-class honors degree, including cap and gown---"

Ha ratos com toda a certeza nas "favelas" de Rio, mas nao somente nos
esgotos, e tambem, nao tengo certeza que os estudantes se usem beretes e
capas para mostrar seus elevacoes de grau.

It`s been more than 50 years since my 2 weeks of Berlitz instruction in
spoken Portuguese, and I`m out of practice and don`t have a dictionary
handy but this is what I tried to write above:

It is certain that there are rats in the "bean shacks" of Rio, but not
only in the sewers, and also, I am not certain that the students use
caps and gowns to show their advancements in grade.

My grammer may be fractured and my spelling may be poor, but I`ve lived
in Lisbon though long ago, and I`ve been to Rio. I think a resident of
Rio could decipher what I`ve written. I could more easily write it it in
Spanish, which we hear in Texas every day, but it`s different from
Portuguese. It`s over 3 months since I was in England, so I`m not so
sure I`m doing so well in English either. Spanglish is often spoken
here.

Best regards, Richard Harrison, KB5WZI