Driver to drive?

[Kevin Aylward]

Jan Panteltje wrote:

On a sunny day (Fri, 19 Sep 2008 19:39:51 GMT) it happened "Kevin
Aylward" <kaExtractThis@kevinaylward.co.uk> wrote in
beTAk.60374$E41.13381@text.news.virginmedia.com>:

If you loo kat the TDA9274 datahseet (the ST DMOS chip), then in the
blockdiagram on page 2 you will see this is exactly what is done
with the lower output MOSFET, combined with opamp makes unity gain.
The top is already a source followwr.
The over current protection same thing, opamps.
It is likely this what makes the Boucherot network not needed.

I doubt it. I haven't seen the data sheet, but it is not usual to be
able to stabilise an amp with what I believe you are describing here.

It is always a good idea to lookuop what we are talking about.

Indeed.

Consider one amp feeding the other, both running open loop, with
overall feedback, to the 1st. Now consider the case where the second
amp is configured with local feedback, to make it a unity buffer,
following the 1st amp. Naively , one might argue that the 2nd stage
now has a wider bandwidth, due to feedback, such that the "new "
system might be stable, i.e. one main rolloff due to the 1st amp.
However, in realty, topologically, nothing changes.

Some people are really good at that stuff, sort of reasonin gI mean.

But if you look at the combination MOSFET - opamp, as John Larkin is
describing in an other post in this thread, then you can treat that
as one 'perfect MOSFET'. Of course it is not really perfect, but you
can make that as stable or unstable as you want. Then basically what
you do is chaining stable blocks together. If you then apply
feedback, you have to use the phase characteristic of all those, and,
as long as you prevent too high frequencies from circulating, it
should be stable, and largely independent of the load.

If we consider calculating the actual LG=B(s).A(s) of the whole system, then
it is identical whther or not there is local feedback around the 2nd stage
or not.

Yes, you can analyse as you describe here, but the result must be identical,
as breaking all loops (if it can actually be done that is). So, it can't be
because there is a local loop that there is no zobel network.

I note the
TDA9274 has one capacitor to roll of in the driver... This is normal,
at least in the amps I designed.

The determine the stability of the system, one needs to break the
loop at a point that breaks *all* feedback paths at once. This point
will be the point directly at the output of the 2nd amp. when this
is done, it is clear that the stabiliy is still due to the total
loop gain of both amops cascaded.

You mean 'open loop gain?'

No. I mean the loop gain. The loop gain is the open loop gain X the beta
factor (e.g. resistive divider). It is the gain around the loop that
matters.

Yes, but he second amp would have gain 1.

But thats my point. Its irrelevent that the closed lop gain of the second
stage is unity when the loop is closed. When you do the stability analyisis
you need to break all the loops. As I said, if you break the loop directly
at the output of the second amp, which breaks both feedback loops at once,
it is obvious that there overal loop gain is not effected by having the 2nd
stage. It is the same loop gain

Excepting for the special cases, e.g. , where feedback is used to
neutralise r.f amps, feedback in general, cannot be used to widen
bandwidth, if the purpose of that wider bandwidth is to achieve
stability, in this type of arrangement

I was not suggesting to widen bandwidth, although strong local
feedback would of course widen the bandwidth of a stage,

But not the BW of the final, overall amp, so the BW of the internal stages
is irrelevant if it is the result of feedback.

What the local loop can buy you is reduced distortion at lower frequencies.

I ran these two circuits up quite a while ago. One has the UGB at the
output, one doesn't.

http://www.kevinaylward.co.uk/ee/circuits/VeryLowDistortionAmp1.jpg
http://www.kevinaylward.co.uk/ee/circuits/VeryLowDistortionAmp2.jpg

The UGB version had to be compensated earlier in frequency, i.e the non UGB
version was significantly faster. Unfortunately, I cant remember much of the
data, and I seem to have lost the SS files;-)

I think one had 0.0001% at 20khz.

Honestly, I have to think about this a bit, maybe run it in spice.
Fact remains that the TDA9274 is the only amp I know that needs no
Boucherot circuit

I would wager it's "non-optimum" designed. You give up a bit if the output
load is not defined, usually. Without the zobel, the load reflected to the
gain stages is all over the place. My guess is that they had a design goal
of minimising the number of external components, which is standard practice
in designing ics, but consequently, gave up some potential performance
improvement.

To wit, There is no such thing as a free lunch...

It seems to exist for US bankers ATM.

Kevin Aylward
www.kevinaylward.co.uk
www.blonddee.co.uk

 

[Kevin Aylward]

Eeyore wrote:

Kevin Aylward wrote:

Eeyore wrote:
John Larkin wrote:
Eeyore wrote:
John Larkin wrote:
Eeyore wrote:

Learn something about LATERAL mosfets that were designed for
audio. I've already given part number and links to data sheets.

That doesn't really matter. The transfer function only needs to
be continuous so that you can close a loop around it, and the fet
needs to be able to stand the peak power dissipation. That can
easily be done with vertical "switching" type fets. A modern
FLOOD architecture [1] works great with most any kind of fet.
Lots of things have changed in the last few decades.

John

[1] Of course you've never heard the term before. I just invented
it.

Fine. Can you elaborate some more on it ? Laterals have some truly
lovely features for audio. The only downside being a slightly
highish Ron. Not really a problem when (as I have) used as many as
6 in parallel (12 mosfets per channel / 24 per amp). They also
match beautifully with no need for source balance resistors (so
some of the Ron loss 'goes away').


An opamp per fet, closing a local loop, feedback from the fet
source, makes each fet look like a perfect unity-gain, fast,
zero-offset device.

Interesting idea. I'll have to chew that one over. I can see
possible problems fron op-amp output overshoot.

I have a simple embodiment of that concept here, done a while ago, in
virtual land;-)

http://www.kevinaylward.co.uk/ee/circuits/VeryLowDistortionAmp2.jpg

Its a push/pull gain loop around the output devices, forcing them to
be unity gain followers.

You can get lower distortion, at the expense of speed, because you
have to compensate earlier.

Common mode feedback at the second stage, allows for enormous dc/lf
gain. cascodes to allow the use of fast small transistors to do all
the main work. Emitter follower buffer to reduce the current swing
in the input pair, as per doug self. Spice says it should be in the
0.0001% , 20Khz range, maybe...

Not exactly short of current mirrors ! ;~)

What gave you the idea ?

Graham

The loop around the output came about from studying a patent that could not
work as claimed, around 1983. This patent claimed distortion reduction by
eliminating miller effect. It had a standard class A gain stage, but used a
cascode. However, the cascode transistor base was connected to the output in
a local feedback loop. This was the claim for distortion reduction. However,
to1st order, the voltage on the base of a cascode transistor, don't effect
anything. The input is current feed, irespective of the base potential,
therfore the could not be any signal feedback. This led me to consider a way
of doing it properly. I also noted that as the base was connected to the
output, the emmiter of the cascode, and the collecter of the driving
transister. hence the collecter still swings the full output, hence, millor
effect is still there. So, that patent was complete nonsense, and my final
circuit was completly different, but it followed from the thought flow of
that patent.

The key point in this approach was to get a push pull drive to both
outputs.,i.e. to avoid low turn off resisters, which kills gain and drive.

Kevin Aylward
www.blonddee.co.uk
www.kevinaylward.co.uk

 

[Kevin Aylward]

Eeyore wrote:

Don Pearce wrote:

Actually the "right" place to connect the feedback sensing resistor
is right out at the speaker itself, via a third sensing wire.

You don't realise just how true that is. I've tuned pcb layouts for
THD just by moving that node. PCB layout guys look perplexed but
thankfully usually do it. In fact there's loads of layout tricks the
PCB guys are hopeless at, loops in particular.

Yes indeed. This is exactly what happened on the 1st PCB prototype of the
MOSFET 1000. Ian did the layout. When it came back, I was only getting 0.02%
thd. Now..this is *exactly* how it happened. I looked at the routing,
immediately noticed that the feedback point was picked up along a high
current trace, took a piece of wire and jumpered across the offending trace,
and thd dropped down to 0.002%. Like, simple putting a wire in || with
another one (that had a tee in it) worked magic!


Kevin Aylward
www.blonddee.co.uk
www.kevinaylward.co.uk

 

[Jon Slaughter]

"Paul Hovnanian P.E." <paul@hovnanian.com> wrote in message
news:48D46820.B9296E2A@hovnanian.com...

Jon Slaughter wrote:

[snip]

My guess is that it makes complete sense but you are just too smart to
understand. Since you believe in giving so much do you accept the 50%
tax
hike on all liberals? Once you guys get your programs going and show us
that
they are worth it we will then give in.

But the blue states are already net contributors while the red states
are net consumers of federal funds. All that the liberals ask is that
they be able to direct their contributions to those who they believe
deserve them.

You folks just want 50% of the liberals money so you can build bridges
to nowhere.

No, I'd rather have you completely out of the picture. Lets split up into
two countries then.. You and all your buddies can run your side any way you
want and let us run our side. Then we will see.

But of course you won't want that or will make excuses and we'll probably
find you sneaking over the border trying to find work in our country. The
reason is because you depend on us... democrats are nothing but parasites
who can't exist on their own.

If it wasn't for republicans(sure the old democrats helped) who built up
this nation for what it is today(and the republicans of today are not those
of old... they are almost just as bad as democrats) you wouldn't have any
chance to implement all your social programs that are completely ruining the
economy and simply don't work.

 

[Jon Slaughter]

"mpm" <mpmillard@aol.com> wrote in message
news:f9856d47-6263-42c0-9eb3-414b5f6de3cc@8g2000hse.googlegroups.com...
On Sep 19, 8:20 pm, "Paul Hovnanian P.E." <p...@hovnanian.com> wrote:

Jim Thompson wrote:

Father/daughter talk...

Come on. Confess. You just changed 'George' to 'Audrey' and 'he' to
'she'.

Actually what we should do is package up those GPA's and sell them off
as beer-blast-backed securities in the secondary financial markets.

Couldn't be any worse than what the Wall Street Republicans did with
our mortgages...

-mpm
---------------------

um... so your saying that democrats had nothing to do with any of the
financial problems? I'd bet it's at least 50/50. But of course your
hyperbole is magnanimous.

 

[RST Engineering (jw)]

Jon, buddy, I like to read your stuff, but until you can snip so that I
don't have to page down continuously, all your good words are sent to that
great bitbucket in the sky.

Jim

--
"It is the mark of an educated mind to be able to entertain a thought
without accepting it."
--Aristotle


"Jon Slaughter" <Jon_Slaughter@Hotmail.com> wrote in message
newsN5Bk.785$x%.733@nlpi070.nbdc.sbc.com...
>

 

[Michael Press]

In article
<88844fd9-4b70-4dea-9cd5-6918d4b2e916@k13g2000hse.googlegroups.com>,
Benj <bjacoby@iwaynet.net> wrote:

On Sep 20, 3:35 am, Michael Press <rub...@pacbell.net> wrote:

I suggested that you look it up. It is obvious that you
will not take my word for any of this.

Why should I 'take your word" on this? I'd rather have YOUR answer
and THEN look it up to see if you are telling the truth!

Anybody can look up the meaning of glass transition temperature
and determine the truth. You already know what I am saying.
Do you feel lucky?

[...]

--
Michael Press

 

[Jon Slaughter]

"Doug B." <c.difficile@gmail.com> wrote in message
news:723da516-e5e5-44cf-91d5-6f8a9cbfd744@8g2000hse.googlegroups.com...

Hello all,

I am working on a circuit to detect the presence of an audio signal
(from a pro sound card) and, from it, drive a resistive load. This
isn't really an amp; I just need to sense a signal, then drive a power
transistor into saturation as long as the audio is present.

I have a working prototype that uses an op amp, open-loop
configuration, driving a power MOSFET. My load is on the drain side,
grounded source. Audio is decoupled through a cap into the non-
inverting input; the inverting side is biased to about 0.1 volt to
keep the output low when no signal is present.

This all works fine, except that I only get output when the audio
signal is in positive polarity, kind of like a class B amp, I guess.

Is there any (simple) way I can get my op amp to output high when the
audio swings low?

Thanks!

Why not just use a resistor, crap and diode?

The diode converts to dc as you don't care about the actual integrity of the
signal, it charges a cap. The cap is what "drives" the fet. When enough
cycles pass to charge up the cap then it will turn on the mosfet independent
of any local variations in the audio signal.

The only problem is that the cap will stay charged(excluding leaking) but
you can discharge through a large resistor. (it has to be large enough so
the cap won't discharge too quickly)

This is a quick way but isn't perfect(it isn't accurate but you don't need
accuracy)

 

[Geezer]

"Corbomite Carrie" <Corbomite@maneuver.org> wrote in message
news:4jlad4phe3ni2fsu6b2vjpe0d7mrkev6tu@4ax.com...

On Sat, 20 Sep 2008 09:53:49 -0700 (PDT), James Arthur
dagmargoodboat@yahoo.com> wrote:

On Sep 19, 4:49 pm, Paul <Quiller...@gmail.com> wrote:
"Naturally, the common people don't want war; neither in Russia
nor in England nor in America, nor for that matter in Germany. That is
understood. But, after all, it is the leaders of the country who
determine the policy and it is always a simple matter to drag the
people along, whether it is a democracy or a fascist dictatorship or a
Parliament or a Communist dictatorship. ...voice or no voice, the
people can always be brought to the bidding of the leaders. That is
easy. All you have to do is to tell them they are being attacked, and
denounce the pacifists for lack of patriotism and exposing the country
to danger. It works the same way in any country."

- Hermann Goring, once a
leading member of
the Nazi Party


Umm, who got us into that war, and what was his party affiliation?

Cheers,
James Arthur


Take this goddamned retarded horseshit somewhere else, you retarded know
nothing fucktards!

Leave s.e.d OUT of your retarded cross-post list.

You have no clue what national security is. The Quiller retard has an
IQ of about 20.

Now FUCK OFF AND DIE... IN YOUR GROUPS, FUCKTARDS.

VERY intelligent response!
I'm impressed that you did so well without outside help.

Geezer

 

[Jon Slaughter]

"John Fields" <jfields@austininstruments.com> wrote in message
news:udlad4dgak10ekam27pu7pqqu5ntbbsf03@4ax.com...

On Sat, 20 Sep 2008 14:28:58 -0500, "Jon Slaughter"
Jon_Slaughter@Hotmail.com> wrote:


"Doug B." <c.difficile@gmail.com> wrote in message
news:723da516-e5e5-44cf-91d5-6f8a9cbfd744@8g2000hse.googlegroups.com...
Hello all,

I am working on a circuit to detect the presence of an audio signal
(from a pro sound card) and, from it, drive a resistive load. This
isn't really an amp; I just need to sense a signal, then drive a power
transistor into saturation as long as the audio is present.

I have a working prototype that uses an op amp, open-loop
configuration, driving a power MOSFET. My load is on the drain side,
grounded source. Audio is decoupled through a cap into the non-
inverting input; the inverting side is biased to about 0.1 volt to
keep the output low when no signal is present.

This all works fine, except that I only get output when the audio
signal is in positive polarity, kind of like a class B amp, I guess.

Is there any (simple) way I can get my op amp to output high when the
audio swings low?

Thanks!

Why not just use a resistor, crap and diode?

---
That's a really shitty way of doing it, Jon.

hehe, why? because it doesn't involve an op amp?

 

[Jon Slaughter]

<M8R-lfwjq11@mailinator.com> wrote in message
news:f64c9249-8aa4-4386-99d9-afa34303cdc1@c58g2000hsc.googlegroups.com...

Hi folks

I have a question about electroadhesion. SRI International recently
came with a way to utilize this with wall climbing robots with the
help of some kind of microgrippers.

From the information on the SRIs page I can read that the microgripper
"clamps using induced electrostatic charges from on-board battery
power".

The question I wanted to ask is, how can you convert the direct
current from a battery to static electricity?

You can't, at least not directly. The electrons generated by a batter must
flow in a loop to complete the circuit which ultimately is a chemical
reaction. The chemical reaction requires, for it to be "perpetuating" that
what whatever gives up electrons are recieved by the other side to complete
the chemical reaction.

You can build a van de graaff generator that is run off a battery and get
static electricity that way.

Electrons in copper are not free because they are governed by the EMF
generated by the chemical reaction. (you can't just peel off an electron and
use it for what you want because then your chemical reactions would not
react)

 

[Jon Slaughter]

<M8R-lfwjq11@mailinator.com> wrote in message
news:03303598-0b79-4794-ae88-a0298c77d651@l64g2000hse.googlegroups.com...

Hi folks

here is another question about static electricity.

Some statically charged materials attract other materials. Is this
attraction caused by the magnetic component in electromagnetic fields?

No, it is caused by polarization. If you take something that is statically
charged and move it close to something else that has mobile electrons, those
electrons will be repelled away creating a positive region which attracts
the electrons. Both negatively charged regions are attracted by the and to
the positive region.

Magnetic fields are an observable effect from electricity and not the other
way around.

 

[Jon Slaughter]

"ehsjr" <ehsjr@NOSPAMverizon.net> wrote in message
news:LOfBk.556$1a2.205@trnddc04...

Jon Slaughter wrote:
"John Fields" <jfields@austininstruments.com> wrote in message
news:udlad4dgak10ekam27pu7pqqu5ntbbsf03@4ax.com...

On Sat, 20 Sep 2008 14:28:58 -0500, "Jon Slaughter"
Jon_Slaughter@Hotmail.com> wrote:


"Doug B." <c.difficile@gmail.com> wrote in message
news:723da516-e5e5-44cf-91d5-6f8a9cbfd744@8g2000hse.googlegroups.com...

Hello all,

I am working on a circuit to detect the presence of an audio signal
(from a pro sound card) and, from it, drive a resistive load. This
isn't really an amp; I just need to sense a signal, then drive a power
transistor into saturation as long as the audio is present.

I have a working prototype that uses an op amp, open-loop
configuration, driving a power MOSFET. My load is on the drain side,
grounded source. Audio is decoupled through a cap into the non-
inverting input; the inverting side is biased to about 0.1 volt to
keep the output low when no signal is present.

This all works fine, except that I only get output when the audio
signal is in positive polarity, kind of like a class B amp, I guess.

Is there any (simple) way I can get my op amp to output high when the
audio swings low?

Thanks!

Why not just use a resistor, crap and diode?

---
That's a really shitty way of doing it, Jon.



hehe, why? because it doesn't involve an op amp?

You are missing the play on words.

hehe... I didn't see it. lol.

It's not only a shitty way but a nasty way too ;/

 

[Jon Slaughter]

"Jim Thompson" <To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote in
message news:dt3bd4ttgsu8ffvj91ckrruclmnjefuhv5@4ax.com...

On Sat, 20 Sep 2008 22:56:41 GMT, nico@puntnl.niks (Nico Coesel)
wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:


On Sat, 20 Sep 2008 08:19:26 GMT, nico@puntnl.niks (Nico Coesel)
wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:


[snip]
E-mailed to me today by daughter-in-law Renee, widow of my second son
Duane.

Jim, just one question: do you have insurances?

Not sure of WHY you are asking... but yes.

An insurance is the same thing: you work for the money you pay to the
insurance company. If someone else slips up, he (or she) gets away
with the money you worked for. Distribution of wealth (communism) is
stupid, but having some (government regulated) insurance that keeps
people on their feet is not.

Insurance companies ARE regulated in the US and are required to have
reserves sufficient to meet claims, otherwise they're taken over by
either state or federal regulators.

This recent fiasco is due to Clinton approving the removal of
restraints on investment banks, who then got into mortgage
_instruments_.


OMG!! Always putting the fucking blame on clinton!!! you know just as well

as I do that it is aliens sabotaging us!!!

 

[Bob Eld]

"Jim Thompson" <To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote in
message news:dt3bd4ttgsu8ffvj91ckrruclmnjefuhv5@4ax.com...

On Sat, 20 Sep 2008 22:56:41 GMT, nico@puntnl.niks (Nico Coesel)
wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:


On Sat, 20 Sep 2008 08:19:26 GMT, nico@puntnl.niks (Nico Coesel)
wrote:

Jim Thompson <To-Email-Use-The-Envelope-Icon@My-Web-Site.com> wrote:


[snip]
E-mailed to me today by daughter-in-law Renee, widow of my second son
Duane.

Jim, just one question: do you have insurances?

Not sure of WHY you are asking... but yes.

An insurance is the same thing: you work for the money you pay to the
insurance company. If someone else slips up, he (or she) gets away
with the money you worked for. Distribution of wealth (communism) is
stupid, but having some (government regulated) insurance that keeps
people on their feet is not.

Insurance companies ARE regulated in the US and are required to have
reserves sufficient to meet claims, otherwise they're taken over by
either state or federal regulators.

This recent fiasco is due to Clinton approving the removal of
restraints on investment banks, who then got into mortgage
_instruments_.

Clinton's fault? Boy there's a republican speaking. Republicans never want
to take any repsonsibility for the mess they create. What bastards. BTW do
you know who Phil Gramm is? Who are the biggest deregulators in congress?
Who championed degregulation? Which presidential candidate said, "I'm for
more deregulation"?

Don't answer. Your answers are nonsequiturs. Why don't you have your
daughter answer instead?

 

[Kris Krieger]

a7yvm109gf5d1@netzero.com wrote in news:db8d4090-22dd-4f64-befe-75920284f4c4
@d1g2000hsg.googlegroups.com:

On Sep 20, 12:33 pm, John Larkin
jjlar...@highNOTlandTHIStechnologyPART.com> wrote:

Atheist Nazis

Really?

http://www.time.com/time/magazine/article/0,9171,796696,00.html

The only officially atheist state ever is Albania. And we all know how
many people died in the horrible Albanian holocaust...

Wrong, the Soviet Union was officially atheistic. Peopel who practiced
religious rites weer jailed or otherrwise punished; cathedrals were closed or
turned into sotrehouses and put to other untilitarian purposes.

ALso, COmmunist China is officially atheistic.

Material dialectsm and all that:
http://filer.case.edu/ngb2/Pages/Impor_Phil_Notes.html

 

[isw]

In article <gb2no5$bin$1@aioe.org>,
Jan Panteltje <pNaonStpealmtje@yahoo.com> wrote:

On a sunny day (Sat, 20 Sep 2008 10:22:09 +0100) it happened Don Pearce
nospam@nospam.com> wrote in
OtGdnZ0izKJfXUnVnZ2dneKdnZydnZ2d@posted.plusnet>:

Actually the "right" place to connect the feedback sensing resistor is
right out at the speaker itself, via a third sensing wire.

Ha, why did I never think of that...
This will eliminate my massive gold feed rods to the woofer.

You will need 2 sensing wires, and a diff amp.

If you really think that's important (and I don't), why not just put the
amplifiers near the speakers? That way, there won't be any nasty
stability problems to deal with.

Isaac

 

[Kris Krieger]

bill.sloman@ieee.org wrote in news:1b32a290-b3da-4da4-9a39-
8cfb9aa37dcc@v13g2000pro.googlegroups.com:

On Sep 21, 7:55 am, John Larkin
jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
[snip]

If everyone abstained before marriage, and was monogamous after, as
the Pope recommends, there would be no AIDS.

And if wishes were horses beggars would ride. Abstinence and fidelity
don't seem to be accessible to a significant proportion of the
population, and thye are th people who spread AIDS.

In all fairness, JL merely pointed out that "If X, then Y".

The main point of contention IMO is "as the Pope recommends", becasue teh
fact is that *most* Eurasian cultures tend to frown upon premarital and
extramarital sex. (I don't know enough about early NAticve American
culture to make any inteligent statement about them, so I won't.) The only
cultures I know of which are fairly casual re: sex are a few Polynesian-
based island cultures that were isolated from Eurasia and therefore had no
exposure to, hence no experience with, Eurasian diseases, or IIRC even
lice, until the Europeans brought them. I can't recall teh refernces now,
but these Eurasian diseases evolved as humans began domesticating animals,
and increasing numbers of humans and animals were living in very close
proximity. (The reason that new flu strains so often erupt in China is due
to the degree to which the Chinese peasantry still live in intimate
proximity with domesticated fowl. Look it up if you doubt me.)

So, rather than only stating "the Pope", John should have said "most
leaders of religions which have their roots in Eurasia".

THe eoor most peopel make today is in assuming that, simply becasue ancient
people had no cell phones or cars, they were stupid. They weren't, and
probably had to be much smarter to survive than do today's coddled masses.
So no, they did not know what 'vibrio cholerae' was, but they could
certainly observe that someone ate oysters ro clams, and developed a elthal
case of the shits - *and* they could observe that there was no way to tell
*which* shellfish were deadly (becuase tehre is no way to visually discern
which are or are nto infected). So, being smart, they said, "Hell, *I'm*
not gonna eat that stuff, and neither is my family!"

THings such as the laws about what can be planted, and when, and wher, were
rooted in observation; laws about not eating meat with dairy were to
pervent waste in an unforgiving environment; laws re: what to use for
weaving cloth could have ben related to observing what made forstronger
cloth versus weaker cloth.

Same goes for sex. Even aside from issues of human jealousy and questions
of who will suport kids (i.e. paternity questions), the same principles of
observation applied to the spread of STDs.


THe problem is that cause-and-effect aer not always observable, leading to
errors in discerning what causes something. So, if soemone spat over his
left shoulder during a hunt, and then narrowly missed getting gored by a
wild boar, he might decide that he escaped harm becaus ehe spit over his
left shoulder. That is part of the cause behind religious errors.

Many religious rules were
probably evolved as methods to reduce communicable diseases.

That probably needs to be put the other way around; the religions that
had adopted sexuall restrictive rules prospered because fewer of their
followers suffered from sexually transmitted diseases; evolution
dictated which religions were successful rather than the rules that
they adopted.

Sorry, but that's simply not the generally-accepted thesis. Observation of
effect, followed by a "don't do that, it's dangerous" rule also just makes
a lot more sense.

John is right on this one.

Sex/drugs/rock-and-roll spread sixty or so nasty viruses and at least
a dozen unpleasant bacteria, all of which are working on their drug
resistance.

Rest and recreation - in the military sense - does just as well. Check
out the epidemiological consequences of the US tropps onrest and
recreation in Australia during the Vietnam war.

Same difference. Casual intimate physical contact is risky. Not only due
to STDs, but also because it's the fastest way to spread *any* communicable
disease, from impetego to TB to the flu, as well as the vectors of disease,
such as head lice and body lice.

My major was in Bacteriology, and I worked as an Epidemiological
Microbioligist for the State of South Carolina for a few years, and then
worked in a Medical microbiology lab - and then, working in the gov.t, I
learned about horrifically nightmarish stuff that nobody ever ought to have
to learn about. So it's not like I'm just making this all up.

People are disease vectors. Having sex with people you don't know well
enough to be certain they're free of communicable disease is risky.
Period. No morality about it because there is no morality to disease -
bacteria, parastes, viruses, all are doing what any other organism does -
trying to survive. Personally, tho', I don't want them using *me* to
survive, so I've never been, and never will be, much of a proponent of
casual sex, for the same reason that I'm not a proponent of sticking one's
hand into the garbage disposal and turning it on.

 

[George's ProSound Company]

It's hard to tell what the Nazis' actual economic policy was, since
neither they nor their philosophy ever really generated any economic
activity besides war.

So the Bush administration had a role model after all!!!
George

 

[Jon Slaughter]

"Robert Baer" <robertbaer@localnet.com> wrote in message
news:jPydnQABK6jgfEjVnZ2dnUVZ_gmdnZ2d@posted.localnet...

..that is what the damn window says with the following incomplete and
useless "Access is denied" message.
Access to what? Where? Why? --- ZERO info. POS.
This happens almost exactly half the way thru the process as seen by the
progress bar.
What is more irritating that all of the work that had been done is then
UNDONE!

How in the #$&@#)^%!%^# can this be fixed?

Usually it is a issue withe file system. I've had that problem on a "bad"
cd. Used a different cd and it worked.