That was scary

[Martin Brown]

On 09/04/2020 06:04, Bill Sloman wrote:

On Thursday, April 9, 2020 at 9:28:13 AM UTC+10, Clifford Heath
wrote:
On 9/4/20 12:32 am, jlarkin@highlandsniptechnology.com wrote:
On Wed, 8 Apr 2020 07:06:44 -0700 (PDT), speff
spehro@gmail.com> wrote:
On Sunday, 5 April 2020 21:25:46 UTC-4, Clifford Heath wrote:
On 6/4/20 11:13 am, jlarkin@highlandsniptechnology.com
wrote:
They just closed the retail pot stores here in Ontario, online
sales only. You'd think they would be considered essential. But
yeah, the food distribution is a taste of what things would be
like in a war situation. Cops outside Costco, people being
ordered around. I'm sure it's like just another day for the
victims^H^H^H folks in Syria or Yemen.
At 7AM, there's at least an hour-long line to get into Safeway.

They're counting people in and out here to cap the number in the
store at one time.

True. I had to wait a whole five minutes in such a queue yesterday.
There were helpful marks on the floor spaced 1.5 metres apart so I
wouldn't get infected by other people in the queue.

My longest wait so far has been 3 hours for a 1 hour shop. Time spent in
the shop is fixed by the one way system to maintain social distancing on
the narrow aisles. You can only move through it at the speed of the
slowest person in front of you.

There were 200 people ahead of me in the queue - partly built up
because of the early morning protected period for elderly shoppers.
They were just letting the last frozen pensioner in at 10.30am. Their
allotted slot is nominally 9-10am.

I now know never to go in the mornings and wait time in the afternoon
was about 40 minutes with about 50 in the queue.

--
Regards,
Martin Brown

 

[David Brown]

On 08/04/2020 21:03, John Larkin wrote:

On Wed, 8 Apr 2020 10:16:42 -0700 (PDT), mpm <mpmillard@aol.com
wrote:

On Tuesday, April 7, 2020 at 5:20:51 PM UTC-4, John Larkin wrote:
On Tue, 7 Apr 2020 20:41:33 +0200, David Brown

Yes, because as we all know, the immune system consists of nothing but
saliva.

That never occurred to me. How do you know that?


Or perhaps you are just talking drivel again.

I feel compelled to mention that an archaic use of the word "drivel" is as a verb to mean "let saliva or mucus flow from the mouth or nose."

So, maybe he really is just talking drivel.

I consider possibilities, given a lot of noisy data. Some people
reject the possibilities they don't like.

Really, a lot of people enjoy disasters and hope they will get worse.
Anything less than a catastrophic projection offends them. And a lot
of people want crisies to exploit.

I take business away from people who don't allow themselves to
consider all the options.

"Considering all the options" is usually a good idea.

Maybe you do that in your electronics business. Maybe you are good at
that - you certainly claim to be, and I have no evidence to the contrary.

But in other fields, you are highly ignorant. And you then fill in the
gaps in your knowledge with any old crap that springs to mind. That is
not "considering the options", it is idiocy.

 

On Fri, 10 Apr 2020 14:13:15 +0200, David Brown
<david.brown@hesbynett.no> wrote:

On 08/04/2020 21:03, John Larkin wrote:
On Wed, 8 Apr 2020 10:16:42 -0700 (PDT), mpm <mpmillard@aol.com
wrote:

On Tuesday, April 7, 2020 at 5:20:51 PM UTC-4, John Larkin wrote:
On Tue, 7 Apr 2020 20:41:33 +0200, David Brown

Yes, because as we all know, the immune system consists of nothing but
saliva.

That never occurred to me. How do you know that?


Or perhaps you are just talking drivel again.

I feel compelled to mention that an archaic use of the word "drivel" is as a verb to mean "let saliva or mucus flow from the mouth or nose."

So, maybe he really is just talking drivel.

I consider possibilities, given a lot of noisy data. Some people
reject the possibilities they don't like.

Really, a lot of people enjoy disasters and hope they will get worse.
Anything less than a catastrophic projection offends them. And a lot
of people want crisies to exploit.

I take business away from people who don't allow themselves to
consider all the options.


"Considering all the options" is usually a good idea.

Maybe you do that in your electronics business. Maybe you are good at
that - you certainly claim to be, and I have no evidence to the contrary.

But in other fields, you are highly ignorant. And you then fill in the
gaps in your knowledge with any old crap that springs to mind. That is
not "considering the options", it is idiocy.

Everyone is highly ignorant about this virus. Various experts and Top
Scientists with Computer Simulations are making wildly different
projections. They would be hilarious if things weren't so serious.
Test density is increasing exponentially but case rates are not
adjusted. My guesses are as good as anybody else' now.

System dynamics and waveforms and measurement and problem solving are
my life, and not always electronics. We don't just design electronics,
we manufacture and sell it. The patterns here are interesting. The
dynamics could well be similar to 1918. Or to the usual winter cold.

What's real is that people who need evaluations and surgeries can't
get into empty hospitals. There's a front-page article in today's SF
Chron about a guy who was scheduled for brain surgery, but now doesn't
know when it might happen.

About 600K people die of cancer in the US every year, out of about 1.8
million disgnosies. They are not being diagnosed now. Do the math.

The damage to our economies is not in doubt either.

Again, people who don't like my thoughts respond with personal
insults, not reasoned discussion. Insults are all they have.

My only objection to stupid insults is that it shows that one more
member of the group is unwilling to think. We need more people capable
of calm reasoning and intelligent discussion.

I do start threads about electronics. This crowd seems uninterested in
electronics.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[Martin Brown]

On 10/04/2020 16:06, jlarkin@highlandsniptechnology.com wrote:

On Fri, 10 Apr 2020 14:13:15 +0200, David Brown
david.brown@hesbynett.no> wrote:

On 08/04/2020 21:03, John Larkin wrote:

Really, a lot of people enjoy disasters and hope they will get worse.
Anything less than a catastrophic projection offends them. And a lot
of people want crisies to exploit.

I take business away from people who don't allow themselves to
consider all the options.

"Considering all the options" is usually a good idea.

Maybe you do that in your electronics business. Maybe you are good at
that - you certainly claim to be, and I have no evidence to the contrary.

But in other fields, you are highly ignorant. And you then fill in the
gaps in your knowledge with any old crap that springs to mind. That is
not "considering the options", it is idiocy.

Everyone is highly ignorant about this virus. Various experts and Top
Scientists with Computer Simulations are making wildly different
projections. They would be hilarious if things weren't so serious.

The Oxford model that made the headlines was shot down in flames very
shortly after they published their preprint. It didn't even pass basic
sanity checks and was wishful thinking. The kindest thing that was said
about their model was that the researchers probably believed what they
had written before it was shredded by online reviewers.

Test density is increasing exponentially but case rates are not
adjusted. My guesses are as good as anybody else' now.

No. You are woefully ignorant and *very* determined to remain so.

The German health system has run an antibody test in one of the hottest
spots on the planet and found that only 14% of the population has
actually got antibodies to the virus at present.

https://www.technologyreview.com/2020/04/09/999015/blood-tests-show-15-of-people-are-now-immune-to-covid-19-in-one-town-in-germany/

At this rate the infection will continue to cause serious problems for
at least another 6 multiples of 2 months or until a viable vaccine is
developed and deployed. Or governments realise that saving every
possible life now at any cost is nothing like an optimal strategy.

System dynamics and waveforms and measurement and problem solving are
my life, and not always electronics. We don't just design electronics,
we manufacture and sell it. The patterns here are interesting. The
dynamics could well be similar to 1918. Or to the usual winter cold.

You clearly don't know what you are talking about but say it anyway.

> The damage to our economies is not in doubt either.

Whilst I agree with this point. I do not agree with your Pollyanna
approach to laissez-faire pandemic control on a wing and a prayer.

The UK has purchased an antibody test that appears not to work well
enough to be remotely useful in the field (and are presently trying to
get their money back). Wired has dissected the problem quite well:

https://www.wired.co.uk/article/coronavirus-antibody-tests-uk-accuracy

--
Regards,
Martin Brown

 

On Friday, April 10, 2020 at 11:06:30 AM UTC-4, jla...@highlandsniptechnology.com wrote:

I do start threads about electronics. This crowd seems uninterested in
electronics.

I'm having a great creative spurt during this Red Death. I'm
frustrated, as often, in that it would be great fun to share,
but sharing wouldn't be fair to the people who've hired me.

Here's a seemingly-trivial circuit that's actually pretty cool:

0.05 5
------+---Rs1---+-----Rs2---+----------//--
| | Q2 |
| +--. . .----+
| | | ^ | |
.-. R1 | - - - .-. R3
| | 10k .--------- | | 100
'-' | | '-'
range | | | Q3 | |\
>------------+ '--. . .----+----|+\ TLV333
| | | ^ | | >--.
| | - - - |-/ |
>| '--------- |/ |
Q1 |------------------------------'
BC857C /|
|
+--------> Vout = 2.5V/A, 2.5V/10mA (low)
|
R2 500k
|
GND

The circuit monitors battery consumption over uA to ~0.5A,
in two ranges to please a 12-bit a-d.

Absolute accuracy isn't particularly critical, otherwise
a FET or a Darlington could replace Q1.

The op-amp is a zero-drift unit with microvolt offset.
The FETs are 50-100 milliohm-ish Rds(on).

The dual FETs solve the problem of wanting to short out the
'low' range sense resistor to reduce its insertion drop,
with minimal measurement error, using FETs whose Rds(on) would
otherwise produce unacceptable error. At full scale, merely
shunting Rs1 with a 100 milliohm FET produces a 100mV error,
double the 50mV Rs1 signal. The R3 - Q3 divider reduces Q2's
Rds(on) measurement error contribution by a factor of about
one thousand.

Cheers,
James

 

On Fri, 10 Apr 2020 16:46:23 +0100, Martin Brown
<'''newspam'''@nezumi.demon.co.uk> wrote:

On 10/04/2020 16:06, jlarkin@highlandsniptechnology.com wrote:
On Fri, 10 Apr 2020 14:13:15 +0200, David Brown
david.brown@hesbynett.no> wrote:

On 08/04/2020 21:03, John Larkin wrote:

Really, a lot of people enjoy disasters and hope they will get worse.
Anything less than a catastrophic projection offends them. And a lot
of people want crisies to exploit.

I take business away from people who don't allow themselves to
consider all the options.

"Considering all the options" is usually a good idea.

Maybe you do that in your electronics business. Maybe you are good at
that - you certainly claim to be, and I have no evidence to the contrary.

But in other fields, you are highly ignorant. And you then fill in the
gaps in your knowledge with any old crap that springs to mind. That is
not "considering the options", it is idiocy.

Everyone is highly ignorant about this virus. Various experts and Top
Scientists with Computer Simulations are making wildly different
projections. They would be hilarious if things weren't so serious.

The Oxford model that made the headlines was shot down in flames very
shortly after they published their preprint. It didn't even pass basic
sanity checks and was wishful thinking. The kindest thing that was said
about their model was that the researchers probably believed what they
had written before it was shredded by online reviewers.

Test density is increasing exponentially but case rates are not
adjusted. My guesses are as good as anybody else' now.

No. You are woefully ignorant and *very* determined to remain so.

The German health system has run an antibody test in one of the hottest
spots on the planet and found that only 14% of the population has
actually got antibodies to the virus at present.

https://www.technologyreview.com/2020/04/09/999015/blood-tests-show-15-of-people-are-now-immune-to-covid-19-in-one-town-in-germany/

That's a useful bit of data. Prefacing it with "willfully ignorant"
isn't. I didn't deliberately avoid seeing the German data.

I have said for some time that we need general-population antibody
studies to understand the dynamics. The usual response was to ridicule
me for suggesting that antibody studies would be worthwhile. Now you
ridicule me because an antibody study has been done. Please explain
that.

The next thing to estimate is what fraction of the population would
catch it if exposed. The current opinion is that "no-one has natural
immunity to coronavirus" but there are counter-cases. If 25% can get
it and 14% have had it, R0 is down about half. So it may peak and
decline soon, as it seems to have done in many places, especially in
europe. Austria and Luxembourg are nice tight test cases. Australia
had a nice bell peak of new cases a couple of weeks ago, with a total
of about 6K confirmed cases so far.

Let the insults flourish.

At this rate the infection will continue to cause serious problems for
at least another 6 multiples of 2 months or until a viable vaccine is
developed and deployed. Or governments realise that saving every
possible life now at any cost is nothing like an optimal strategy.

That's one common prediction: the virus will be a serious cause of
death for another year or more and nothing short of a vaccine will
ever stop it. Noted health scientists like Bill Gates have told us so.

System dynamics and waveforms and measurement and problem solving are
my life, and not always electronics. We don't just design electronics,
we manufacture and sell it. The patterns here are interesting. The
dynamics could well be similar to 1918. Or to the usual winter cold.

You clearly don't know what you are talking about but say it anyway.

The damage to our economies is not in doubt either.

Whilst I agree with this point. I do not agree with your Pollyanna
approach to laissez-faire pandemic control on a wing and a prayer.

Cite my saying anything like that. I have no power over the situation
and hence no "approach." I have mostly considered possibilities of the
dynamics. I have suggested that fear and panic are not productive.

I do predict a massive surplus of cheap never-used ventilators.

The UK has purchased an antibody test that appears not to work well
enough to be remotely useful in the field (and are presently trying to
get their money back). Wired has dissected the problem quite well:

https://www.wired.co.uk/article/coronavirus-antibody-tests-uk-accuracy

There seems to be a lot of hostility to antibody testing.



--

John Larkin Highland Technology, Inc

Science teaches us to doubt.

Claude Bernard

 

[John Larkin]

On Fri, 10 Apr 2020 10:29:19 -0700 (PDT), dagmargoodboat@yahoo.com
wrote:

On Friday, April 10, 2020 at 11:06:30 AM UTC-4, jla...@highlandsniptechnology.com wrote:

I do start threads about electronics. This crowd seems uninterested in
electronics.

I'm having a great creative spurt during this Red Death. I'm
frustrated, as often, in that it would be great fun to share,
but sharing wouldn't be fair to the people who've hired me.

Here's a seemingly-trivial circuit that's actually pretty cool:

0.05 5
------+---Rs1---+-----Rs2---+----------//--
| | Q2 |
| +--. . .----+
| | | ^ | |
.-. R1 | - - - .-. R3
| | 10k .--------- | | 100
'-' | | '-'
range | | | Q3 | |\
------------+ '--. . .----+----|+\ TLV333
| | | ^ | | >--.
| | - - - |-/ |
| '--------- |/ |
Q1 |------------------------------'
BC857C /|
|
+--------> Vout = 2.5V/A, 2.5V/10mA (low)
|
R2 500k
|
GND

The circuit monitors battery consumption over uA to ~0.5A,
in two ranges to please a 12-bit a-d.

Absolute accuracy isn't particularly critical, otherwise
a FET or a Darlington could replace Q1.

The op-amp is a zero-drift unit with microvolt offset.
The FETs are 50-100 milliohm-ish Rds(on).

The dual FETs solve the problem of wanting to short out the
'low' range sense resistor to reduce its insertion drop,
with minimal measurement error, using FETs whose Rds(on) would
otherwise produce unacceptable error. At full scale, merely
shunting Rs1 with a 100 milliohm FET produces a 100mV error,
double the 50mV Rs1 signal. The R3 - Q3 divider reduces Q2's
Rds(on) measurement error contribution by a factor of about
one thousand.

Cheers,
James

You might also use one small sense resistor and gain-switch a
zero-offset opamp.

It's just a battery monitor, so maybe not range switch at all?

--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

[George Herold]

On Friday, April 10, 2020 at 1:29:25 PM UTC-4, dagmarg...@yahoo.com wrote:

On Friday, April 10, 2020 at 11:06:30 AM UTC-4, jla...@highlandsniptechnology.com wrote:

I do start threads about electronics. This crowd seems uninterested in
electronics.

I'm having a great creative spurt during this Red Death. I'm
frustrated, as often, in that it would be great fun to share,
but sharing wouldn't be fair to the people who've hired me.

Here's a seemingly-trivial circuit that's actually pretty cool:

0.05 5
------+---Rs1---+-----Rs2---+----------//--
| | Q2 |
| +--. . .----+
| | | ^ | |
.-. R1 | - - - .-. R3
| | 10k .--------- | | 100
'-' | | '-'
range | | | Q3 | |\
------------+ '--. . .----+----|+\ TLV333
| | | ^ | | >--.
| | - - - |-/ |
| '--------- |/ |
Q1 |------------------------------'
BC857C /|
|
+--------> Vout = 2.5V/A, 2.5V/10mA (low)
|
R2 500k
|
GND

The circuit monitors battery consumption over uA to ~0.5A,
in two ranges to please a 12-bit a-d.

Hi James. What's the opamp inverting input hooked to?
I'm not seeing how it works.
(I tried several nodes...)

George h.

Absolute accuracy isn't particularly critical, otherwise
a FET or a Darlington could replace Q1.

The op-amp is a zero-drift unit with microvolt offset.
The FETs are 50-100 milliohm-ish Rds(on).

The dual FETs solve the problem of wanting to short out the
'low' range sense resistor to reduce its insertion drop,
with minimal measurement error, using FETs whose Rds(on) would
otherwise produce unacceptable error. At full scale, merely
shunting Rs1 with a 100 milliohm FET produces a 100mV error,
double the 50mV Rs1 signal. The R3 - Q3 divider reduces Q2's
Rds(on) measurement error contribution by a factor of about
one thousand.

Cheers,
James

 

On Friday, April 10, 2020 at 11:46:30 AM UTC-4, Martin Brown wrote:

The German health system has run an antibody test in one of the hottest
spots on the planet and found that only 14% of the population has
actually got antibodies to the virus at present.

https://www.technologyreview.com/2020/04/09/999015/blood-tests-show-15-of-people-are-now-immune-to-covid-19-in-one-town-in-germany/

Observations:
a) That's a huge figure. OTOH, it's not close to being everybody, which
bespeaks a finite transmissibility.
b) One of my buddies, exposed to Chinese nationals returning from China,
almost certainly had this beast in January, before even the U.S.'
first known case. ISTM there's a high probability Peking Lung was on
the loose in the U.S. population weeks before anyone recognized it.
c) If the New York physician's video I posted in the "80% of NYC"
thread is accurate, then we can stop transmission fairly
effectively with simple hygiene.

Cheers,
James Arthur

 

[David Brown]

On 10/04/2020 17:06, jlarkin@highlandsniptechnology.com wrote:

On Fri, 10 Apr 2020 14:13:15 +0200, David Brown
david.brown@hesbynett.no> wrote:

On 08/04/2020 21:03, John Larkin wrote:
On Wed, 8 Apr 2020 10:16:42 -0700 (PDT), mpm <mpmillard@aol.com
wrote:

On Tuesday, April 7, 2020 at 5:20:51 PM UTC-4, John Larkin wrote:
On Tue, 7 Apr 2020 20:41:33 +0200, David Brown

Yes, because as we all know, the immune system consists of nothing but
saliva.

That never occurred to me. How do you know that?


Or perhaps you are just talking drivel again.

I feel compelled to mention that an archaic use of the word "drivel" is as a verb to mean "let saliva or mucus flow from the mouth or nose."

So, maybe he really is just talking drivel.

I consider possibilities, given a lot of noisy data. Some people
reject the possibilities they don't like.

Really, a lot of people enjoy disasters and hope they will get worse.
Anything less than a catastrophic projection offends them. And a lot
of people want crisies to exploit.

I take business away from people who don't allow themselves to
consider all the options.


"Considering all the options" is usually a good idea.

Maybe you do that in your electronics business. Maybe you are good at
that - you certainly claim to be, and I have no evidence to the contrary.

But in other fields, you are highly ignorant. And you then fill in the
gaps in your knowledge with any old crap that springs to mind. That is
not "considering the options", it is idiocy.

Everyone is highly ignorant about this virus.

No. Some people - like you - are so highly ignorant you don't even
understand what you are ignorant about. Others know a great deal more.
No one knows everything, and there are lots of aspects that no one yet
knows.

Various experts and Top
Scientists with Computer Simulations are making wildly different
projections. They would be hilarious if things weren't so serious.
Test density is increasing exponentially but case rates are not
adjusted. My guesses are as good as anybody else' now.

It is that last part it is so absurd. No, your guesses are /not/ as
good as anybody else's. That is the whole point of letting experts make
/qualified/ guesses. When there is a gap in scientific knowledge, that
does /not/ mean that any twit with an imagination and no common sense
can fill in that gap.

System dynamics and waveforms and measurement and problem solving are
my life, and not always electronics. We don't just design electronics,
we manufacture and sell it. The patterns here are interesting. The
dynamics could well be similar to 1918. Or to the usual winter cold.

If you are scientific about your electronics design, you'll understand
the concepts of interpolation and extrapolation. These are valid ways
of estimating a gap in your data, when there is enough known data to
form a reasonable hypothesis of the pattern. An entirely /unreasonable/
way would be to ask someone who hasn't seen any of the known data to
pick a number. Yet that is what you seem to be espousing in other fields.

What's real is that people who need evaluations and surgeries can't
get into empty hospitals. There's a front-page article in today's SF
Chron about a guy who was scheduled for brain surgery, but now doesn't
know when it might happen.

Of course that's a problem. That is one of the reasons for wanting a
lockdown, so that the Covid-19 pandemic does not overwhelm the medical
services.

About 600K people die of cancer in the US every year, out of about 1.8
million disgnosies. They are not being diagnosed now. Do the math.

Have you any idea of how many people would die if there wasn't a
lockdown? Vastly more than those 600K people would die directly from
Covid-19 - it would likely be millions (we are just talking about the
USA here). Common estimates (and they are only estimates) are that you
need 60% infected to get herd immunity (though there is now severe doubt
about how immunity you get after recovery). And with a totally
overwhelmed health service, between 5% and 10% will die. So without
working hard to limit the spread of this virus, it would be unsurprising
to see 10 to 20 million people die in the USA alone.

And then a lot more than 600K would die of cancer, because so many
health carers have died too.

The damage to our economies is not in doubt either.

No.

Again, people who don't like my thoughts respond with personal
insults, not reasoned discussion. Insults are all they have.

People have tried reasoned discussion, but it is not really possible
with you. It only makes sense to have a rational discussion with a
rational person.

My only objection to stupid insults is that it shows that one more
member of the group is unwilling to think. We need more people capable
of calm reasoning and intelligent discussion.

You are usually calm - I'll give you that. Reasoning and intelligent?
No, that is not you. (Or to be fairer and more accurate, you don't
apply reason and intelligence to thinking about many of the topics
discussed in s.e.d. Perhaps you could, but you don't.)

I do start threads about electronics. This crowd seems uninterested in
electronics.

I'm not terribly interested in analogue electronics. I'm not much good
at it - it's simply not my field. I like digital electronics, because
it's easy, and my main job is programming microcontrollers. So I
sometimes join in threads if these turn up.

 

[George Herold]

On Friday, April 10, 2020 at 4:06:57 PM UTC-4, piglet wrote:

On 10/04/2020 7:39 pm, George Herold wrote:
On Friday, April 10, 2020 at 1:29:25 PM UTC-4, dagmarg...@yahoo.com wrote:
On Friday, April 10, 2020 at 11:06:30 AM UTC-4, jla...@highlandsniptechnology.com wrote:

I do start threads about electronics. This crowd seems uninterested in
electronics.

I'm having a great creative spurt during this Red Death. I'm
frustrated, as often, in that it would be great fun to share,
but sharing wouldn't be fair to the people who've hired me.

Here's a seemingly-trivial circuit that's actually pretty cool:

0.05 5
------+---Rs1---+-----Rs2---+----------//--
| | Q2 |
| +--. . .----+
| | | ^ | |
.-. R1 | - - - .-. R3
| | 10k .--------- | | 100
'-' | | '-'
range | | | Q3 | |\
------------+ '--. . .----+----|+\ TLV333
| | | ^ | | >--.
| | - - - |-/ |
| '--------- |/ |
Q1 |------------------------------'
BC857C /|
|
+--------> Vout = 2.5V/A, 2.5V/10mA (low)
|
R2 500k
|
GND

The circuit monitors battery consumption over uA to ~0.5A,
in two ranges to please a 12-bit a-d.

Hi James. What's the opamp inverting input hooked to?
I'm not seeing how it works.
(I tried several nodes...)

George h.

Hi George, I think the inverting input connects to the junction of R1
and Q1 emitter.

piglet

Thanks!
GH

 

On Friday, April 10, 2020 at 2:24:49 PM UTC-4, John Larkin wrote:

On Fri, 10 Apr 2020 10:29:19 -0700 (PDT), dagmargoodboat@yahoo.com
wrote:

On Friday, April 10, 2020 at 11:06:30 AM UTC-4, jla...@highlandsniptechnology.com wrote:

I do start threads about electronics. This crowd seems uninterested in
electronics.

I'm having a great creative spurt during this Red Death. I'm
frustrated, as often, in that it would be great fun to share,
but sharing wouldn't be fair to the people who've hired me.

Here's a seemingly-trivial circuit that's actually pretty cool:

0.05 5
------+---Rs1---+-----Rs2---+----------//--
| | Q2 |
| +--. . .----+
| | | ^ | |
.-. R1 | - - - .-. R3
| | 10k .--------- | | 100
'-' | | '-'
range | | | Q3 | |\
------------+ '--. . .----+----|+\ TLV333
| | | ^ | | >--.
| | - - - .---|-/ |
| '--------- | |/ |
+----------------------' |
| |
'>| |
Q1 |------------------------------'
BC857C /|
|
+--------> Vout = 2.5V/A, 2.5V/10mA (low)
|
R2 500k
|
GND

The circuit monitors battery consumption over uA to ~0.5A,
in two ranges to please a 12-bit a-d.

Absolute accuracy isn't particularly critical, otherwise
a FET or a Darlington could replace Q1.

The op-amp is a zero-drift unit with microvolt offset.
The FETs are 50-100 milliohm-ish Rds(on).

The dual FETs solve the problem of wanting to short out the
'low' range sense resistor to reduce its insertion drop,
with minimal measurement error, using FETs whose Rds(on) would
otherwise produce unacceptable error. At full scale, merely
shunting Rs1 with a 100 milliohm FET produces a 100mV error,
double the 50mV Rs1 signal. The R3 - Q3 divider reduces Q2's
Rds(on) measurement error contribution by a factor of about
one thousand.

Cheers,
James

You might also use one small sense resistor

Can't. 10uA through a 50 milliohm sense resistor is 500nV.

> and gain-switch a zero-offset opamp.

That is a zero-offset R-R opamp. But at these low signal levels,
switching the input signal rather than the opamp gain is
<calculates furiously> a bazillion times more accurate.

> It's just a battery monitor, so maybe not range switch at all?

Not enough resolution that way. I need to tabulate the total
energy while we yank out 500mA for a handful of seconds, and
also while we idle at 30 or 50uA for hour after hour.

Given a 12-bit ADC, 2.5V/A => 244uA per lsb. That's not nearly
good enough. (That's with 12uV/lsb at the sense resistor.)

The switchable sense resistor arrangement improves the resolution
to 2.44uA per lsb, which seems pretty reasonable. And the sense
voltage stays large enough that I won't have to fret thermocouple
voltages everywhere.


Cheers,
James

 

On Friday, April 10, 2020 at 2:39:23 PM UTC-4, George Herold wrote:

On Friday, April 10, 2020 at 1:29:25 PM UTC-4, dagmarg...@yahoo.com wrote:
On Friday, April 10, 2020 at 11:06:30 AM UTC-4, jla...@highlandsniptechnology.com wrote:

I do start threads about electronics. This crowd seems uninterested in
electronics.

I'm having a great creative spurt during this Red Death. I'm
frustrated, as often, in that it would be great fun to share,
but sharing wouldn't be fair to the people who've hired me.

Here's a seemingly-trivial circuit that's actually pretty cool:

0.05 5
------+---Rs1---+-----Rs2---+----------//--
| | Q2 |
| +--. . .----+
| | | ^ | |
.-. R1 | - - - .-. R3
| | 10k .--------- | | 100
'-' | | '-'
range | | | Q3 | |\
------------+ '--. . .----+----|+\ TLV333
| | | ^ | | >--.
| | - - - .---|-/ |
| '--------- | |/ |
+----------------------' |
| |
'>| |
Q1 |------------------------------'
BC857C /|
|
+--------> Vout = 2.5V/A, 2.5V/10mA (low)
|
R2 500k
|
GND


The circuit monitors battery consumption over uA to ~0.5A,
in two ranges to please a 12-bit a-d.

Hi James. What's the opamp inverting input hooked to?
I'm not seeing how it works.
(I tried several nodes...)

George h.

Ooops, thanks. Fixed it above.

Cheers,
James

 

On Friday, April 10, 2020 at 4:09:00 PM UTC-4, piglet wrote:

On 10/04/2020 6:29 pm, dagmargoodboat@yahoo.com wrote:
On Friday, April 10, 2020 at 11:06:30 AM UTC-4, jla...@highlandsniptechnology.com wrote:

I do start threads about electronics. This crowd seems uninterested in
electronics.

I'm having a great creative spurt during this Red Death. I'm
frustrated, as often, in that it would be great fun to share,
but sharing wouldn't be fair to the people who've hired me.

Here's a seemingly-trivial circuit that's actually pretty cool:

0.05 5
------+---Rs1---+-----Rs2---+----------//--
| | Q2 |
| +--.-. .----+
| | | ^ | |
.-. R1 | - - - .-. R3
| | 10k .--------- | | 100
'-' | | '-'
range | | | Q3 | |\
------------+ '--.-. .----+----|+\ TLV333
| | | ^ | | >--.
| | - - - .---|-/ |
| '--------- | |/ |
+----------------------' |
| |
'>| |
Q1 |------------------------------'
BC857C /|
|
+--------> Vout = 2.5V/A (high range), 2.5V/10mA (low range)
|
R2 500k
|
GND

The circuit monitors battery consumption over uA to ~0.5A,
in two ranges to please a 12-bit a-d.

Absolute accuracy isn't particularly critical, otherwise
a FET or a Darlington could replace Q1.

The op-amp is a zero-drift unit with microvolt offset.
The FETs are 50-100 milliohm-ish Rds(on).

The dual FETs solve the problem of wanting to short out the
'low' range sense resistor Rs2 to reduce its insertion drop,
with minimal measurement error, using FETs whose Rds(on) would
otherwise produce unacceptable error. At full scale, merely
shunting Rs2 with a 100 milliohm FET produces a 100mV error,
double the 50mV Rs1 signal. The R3 - Q3 divider reduces Q2's
Rds(on) measurement error contribution by a factor of about
one thousand.

(text and diagram corrected)

Thanks James, one snag I foresee is what happens when load current jumps
to 0.5A when the ranging still has Q2 off?

piglet

In real life the same uC that switches on the heavy load will
simply switch the monitor's current range, first. But just to
be safe, there's a schottky across Rs2 that clamps its drop
to ~300mV-ish worst case, IIRC. Otherwise, a wild uC could
wreak all sorts of havoc.

It's kind of a hassle keeping an SMD sense resistor dissipation
(and insertion drop) low enough, while still producing enough
signal for a good measurement. This circuit juggles those
conflicting requirements, and still returns a decently
accurate answer.

Cheers,
James Arthur

 

[John Larkin]

On Fri, 10 Apr 2020 13:09:26 -0700 (PDT), dagmargoodboat@yahoo.com
wrote:

On Friday, April 10, 2020 at 2:24:49 PM UTC-4, John Larkin wrote:
On Fri, 10 Apr 2020 10:29:19 -0700 (PDT), dagmargoodboat@yahoo.com
wrote:

On Friday, April 10, 2020 at 11:06:30 AM UTC-4, jla...@highlandsniptechnology.com wrote:

I do start threads about electronics. This crowd seems uninterested in
electronics.

I'm having a great creative spurt during this Red Death. I'm
frustrated, as often, in that it would be great fun to share,
but sharing wouldn't be fair to the people who've hired me.

Here's a seemingly-trivial circuit that's actually pretty cool:

0.05 5
------+---Rs1---+-----Rs2---+----------//--
| | Q2 |
| +--. . .----+
| | | ^ | |
.-. R1 | - - - .-. R3
| | 10k .--------- | | 100
'-' | | '-'
range | | | Q3 | |\
------------+ '--. . .----+----|+\ TLV333
| | | ^ | | >--.
| | - - - .---|-/ |
| '--------- | |/ |
+----------------------' |
| |
'>| |
Q1 |------------------------------'
BC857C /|
|
+--------> Vout = 2.5V/A, 2.5V/10mA (low)
|
R2 500k
|
GND

The circuit monitors battery consumption over uA to ~0.5A,
in two ranges to please a 12-bit a-d.

Absolute accuracy isn't particularly critical, otherwise
a FET or a Darlington could replace Q1.

The op-amp is a zero-drift unit with microvolt offset.
The FETs are 50-100 milliohm-ish Rds(on).

The dual FETs solve the problem of wanting to short out the
'low' range sense resistor to reduce its insertion drop,
with minimal measurement error, using FETs whose Rds(on) would
otherwise produce unacceptable error. At full scale, merely
shunting Rs1 with a 100 milliohm FET produces a 100mV error,
double the 50mV Rs1 signal. The R3 - Q3 divider reduces Q2's
Rds(on) measurement error contribution by a factor of about
one thousand.

Cheers,
James

You might also use one small sense resistor

Can't. 10uA through a 50 milliohm sense resistor is 500nV.

and gain-switch a zero-offset opamp.

That is a zero-offset R-R opamp. But at these low signal levels,
switching the input signal rather than the opamp gain is
calculates furiously> a bazillion times more accurate.

It's just a battery monitor, so maybe not range switch at all?

Not enough resolution that way. I need to tabulate the total
energy while we yank out 500mA for a handful of seconds, and
also while we idle at 30 or 50uA for hour after hour.

Sounds a bit compulsive to me. Is it a tiny battery?

Given a 12-bit ADC, 2.5V/A => 244uA per lsb. That's not nearly
good enough. (That's with 12uV/lsb at the sense resistor.)

The switchable sense resistor arrangement improves the resolution
to 2.44uA per lsb, which seems pretty reasonable. And the sense
voltage stays large enough that I won't have to fret thermocouple
voltages everywhere.


Cheers,
James

I don't suppose you could tolerate a diode drop. Get the log of
current.

--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com

 

On Friday, April 10, 2020 at 4:10:29 PM UTC-4, John Larkin wrote:

On Fri, 10 Apr 2020 20:46:34 +0200, David Brown
david.brown@hesbynett.no> wrote:

On 10/04/2020 17:06, jlarkin@highlandsniptechnology.com wrote:
On Fri, 10 Apr 2020 14:13:15 +0200, David Brown
david.brown@hesbynett.no> wrote:

On 08/04/2020 21:03, John Larkin wrote:
On Wed, 8 Apr 2020 10:16:42 -0700 (PDT), mpm <mpmillard@aol.com
wrote:

On Tuesday, April 7, 2020 at 5:20:51 PM UTC-4, John Larkin wrote:
On Tue, 7 Apr 2020 20:41:33 +0200, David Brown

Yes, because as we all know, the immune system consists of nothing but
saliva.

That never occurred to me. How do you know that?


Or perhaps you are just talking drivel again.

I feel compelled to mention that an archaic use of the word "drivel" is as a verb to mean "let saliva or mucus flow from the mouth or nose."

So, maybe he really is just talking drivel.

I consider possibilities, given a lot of noisy data. Some people
reject the possibilities they don't like.

Really, a lot of people enjoy disasters and hope they will get worse.
Anything less than a catastrophic projection offends them. And a lot
of people want crisies to exploit.

I take business away from people who don't allow themselves to
consider all the options.


"Considering all the options" is usually a good idea.

Maybe you do that in your electronics business. Maybe you are good at
that - you certainly claim to be, and I have no evidence to the contrary.

But in other fields, you are highly ignorant. And you then fill in the
gaps in your knowledge with any old crap that springs to mind. That is
not "considering the options", it is idiocy.

Everyone is highly ignorant about this virus.

No. Some people - like you - are so highly ignorant you don't even
understand what you are ignorant about. Others know a great deal more.
No one knows everything, and there are lots of aspects that no one yet
knows.

Various experts and Top
Scientists with Computer Simulations are making wildly different
projections. They would be hilarious if things weren't so serious.
Test density is increasing exponentially but case rates are not
adjusted. My guesses are as good as anybody else' now.


It is that last part it is so absurd. No, your guesses are /not/ as
good as anybody else's. That is the whole point of letting experts make
/qualified/ guesses. When there is a gap in scientific knowledge, that
does /not/ mean that any twit with an imagination and no common sense
can fill in that gap.

System dynamics and waveforms and measurement and problem solving are
my life, and not always electronics. We don't just design electronics,
we manufacture and sell it. The patterns here are interesting. The
dynamics could well be similar to 1918. Or to the usual winter cold.


If you are scientific about your electronics design, you'll understand
the concepts of interpolation and extrapolation.

Yes, I have been told that I don't understand exponential growth.

If you think you don't understand these growth rates now, just imagine
how much you won't understand them a few days from now!

Grins,
James

 

[piglet]

On 10/04/2020 6:29 pm, dagmargoodboat@yahoo.com wrote:

On Friday, April 10, 2020 at 11:06:30 AM UTC-4, jla...@highlandsniptechnology.com wrote:

I do start threads about electronics. This crowd seems uninterested in
electronics.

I'm having a great creative spurt during this Red Death. I'm
frustrated, as often, in that it would be great fun to share,
but sharing wouldn't be fair to the people who've hired me.

Here's a seemingly-trivial circuit that's actually pretty cool:

0.05 5
------+---Rs1---+-----Rs2---+----------//--
| | Q2 |
| +--. . .----+
| | | ^ | |
.-. R1 | - - - .-. R3
| | 10k .--------- | | 100
'-' | | '-'
range | | | Q3 | |\
------------+ '--. . .----+----|+\ TLV333
| | | ^ | | >--.
| | - - - |-/ |
| '--------- |/ |
Q1 |------------------------------'
BC857C /|
|
+--------> Vout = 2.5V/A, 2.5V/10mA (low)
|
R2 500k
|
GND

The circuit monitors battery consumption over uA to ~0.5A,
in two ranges to please a 12-bit a-d.

Absolute accuracy isn't particularly critical, otherwise
a FET or a Darlington could replace Q1.

The op-amp is a zero-drift unit with microvolt offset.
The FETs are 50-100 milliohm-ish Rds(on).

The dual FETs solve the problem of wanting to short out the
'low' range sense resistor to reduce its insertion drop,
with minimal measurement error, using FETs whose Rds(on) would
otherwise produce unacceptable error. At full scale, merely
shunting Rs1 with a 100 milliohm FET produces a 100mV error,
double the 50mV Rs1 signal. The R3 - Q3 divider reduces Q2's
Rds(on) measurement error contribution by a factor of about
one thousand.

Cheers,
James

Thanks James, one snag I foresee is what happens when load current jumps
to 0.5A when the ranging still has Q2 off?

piglet

 

On Friday, April 10, 2020 at 4:27:33 PM UTC-4, John Larkin wrote:

On Fri, 10 Apr 2020 13:09:26 -0700 (PDT), dagmargoodboat@yahoo.com
wrote:

On Friday, April 10, 2020 at 2:24:49 PM UTC-4, John Larkin wrote:
On Fri, 10 Apr 2020 10:29:19 -0700 (PDT), dagmargoodboat@yahoo.com
wrote:

On Friday, April 10, 2020 at 11:06:30 AM UTC-4, jla...@highlandsniptechnology.com wrote:

I do start threads about electronics. This crowd seems uninterested in
electronics.

I'm having a great creative spurt during this Red Death. I'm
frustrated, as often, in that it would be great fun to share,
but sharing wouldn't be fair to the people who've hired me.

Here's a seemingly-trivial circuit that's actually pretty cool:

0.05 5
------+---Rs1---+-----Rs2---+----------//--
| | Q2 |
| +--. . .----+
| | | ^ | |
.-. R1 | - - - .-. R3
| | 10k .--------- | | 100
'-' | | '-'
range | | | Q3 | |\
------------+ '--. . .----+----|+\ TLV333
| | | ^ | | >--.
| | - - - .---|-/ |
| '--------- | |/ |
+----------------------' |
| |
'>| |
Q1 |------------------------------'
BC857C /|
|
+--------> Vout = 2.5V/A, 2.5V/10mA (low)
|
R2 500k
|
GND

The circuit monitors battery consumption over uA to ~0.5A,
in two ranges to please a 12-bit a-d.

Absolute accuracy isn't particularly critical, otherwise
a FET or a Darlington could replace Q1.

The op-amp is a zero-drift unit with microvolt offset.
The FETs are 50-100 milliohm-ish Rds(on).

The dual FETs solve the problem of wanting to short out the
'low' range sense resistor to reduce its insertion drop,
with minimal measurement error, using FETs whose Rds(on) would
otherwise produce unacceptable error. At full scale, merely
shunting Rs1 with a 100 milliohm FET produces a 100mV error,
double the 50mV Rs1 signal. The R3 - Q3 divider reduces Q2's
Rds(on) measurement error contribution by a factor of about
one thousand.

Cheers,
James

You might also use one small sense resistor

Can't. 10uA through a 50 milliohm sense resistor is 500nV.

and gain-switch a zero-offset opamp.

That is a zero-offset R-R opamp. But at these low signal levels,
switching the input signal rather than the opamp gain is
calculates furiously> a bazillion times more accurate.

It's just a battery monitor, so maybe not range switch at all?

Not enough resolution that way. I need to tabulate the total
energy while we yank out 500mA for a handful of seconds, and
also while we idle at 30 or 50uA for hour after hour.

Sounds a bit compulsive to me. Is it a tiny battery?

It's demanding, but it's vital to know the state-of-charge. Which
is sort of a pain when much of the time-integrated discharge
comes from Iq. But that's why we get the hard stuff, right?

Given a 12-bit ADC, 2.5V/A => 244uA per lsb. That's not nearly
good enough. (That's with 12uV/lsb at the sense resistor.)

The switchable sense resistor arrangement improves the resolution
to 2.44uA per lsb, which seems pretty reasonable. And the sense
voltage stays large enough that I won't have to fret thermocouple
voltages everywhere.

I don't suppose you could tolerate a diode drop.

<faints> <Thunk!>

Cheers,
James

 

[piglet]

On 10/04/2020 7:39 pm, George Herold wrote:

On Friday, April 10, 2020 at 1:29:25 PM UTC-4, dagmarg...@yahoo.com wrote:
On Friday, April 10, 2020 at 11:06:30 AM UTC-4, jla...@highlandsniptechnology.com wrote:

I do start threads about electronics. This crowd seems uninterested in
electronics.

I'm having a great creative spurt during this Red Death. I'm
frustrated, as often, in that it would be great fun to share,
but sharing wouldn't be fair to the people who've hired me.

Here's a seemingly-trivial circuit that's actually pretty cool:

0.05 5
------+---Rs1---+-----Rs2---+----------//--
| | Q2 |
| +--. . .----+
| | | ^ | |
.-. R1 | - - - .-. R3
| | 10k .--------- | | 100
'-' | | '-'
range | | | Q3 | |\
------------+ '--. . .----+----|+\ TLV333
| | | ^ | | >--.
| | - - - |-/ |
| '--------- |/ |
Q1 |------------------------------'
BC857C /|
|
+--------> Vout = 2.5V/A, 2.5V/10mA (low)
|
R2 500k
|
GND

The circuit monitors battery consumption over uA to ~0.5A,
in two ranges to please a 12-bit a-d.

Hi James. What's the opamp inverting input hooked to?
I'm not seeing how it works.
(I tried several nodes...)

George h.

Hi George, I think the inverting input connects to the junction of R1
and Q1 emitter.

piglet

 

[John Larkin]

On Fri, 10 Apr 2020 20:46:34 +0200, David Brown
<david.brown@hesbynett.no> wrote:

On 10/04/2020 17:06, jlarkin@highlandsniptechnology.com wrote:
On Fri, 10 Apr 2020 14:13:15 +0200, David Brown
david.brown@hesbynett.no> wrote:

On 08/04/2020 21:03, John Larkin wrote:
On Wed, 8 Apr 2020 10:16:42 -0700 (PDT), mpm <mpmillard@aol.com
wrote:

On Tuesday, April 7, 2020 at 5:20:51 PM UTC-4, John Larkin wrote:
On Tue, 7 Apr 2020 20:41:33 +0200, David Brown

Yes, because as we all know, the immune system consists of nothing but
saliva.

That never occurred to me. How do you know that?


Or perhaps you are just talking drivel again.

I feel compelled to mention that an archaic use of the word "drivel" is as a verb to mean "let saliva or mucus flow from the mouth or nose."

So, maybe he really is just talking drivel.

I consider possibilities, given a lot of noisy data. Some people
reject the possibilities they don't like.

Really, a lot of people enjoy disasters and hope they will get worse.
Anything less than a catastrophic projection offends them. And a lot
of people want crisies to exploit.

I take business away from people who don't allow themselves to
consider all the options.


"Considering all the options" is usually a good idea.

Maybe you do that in your electronics business. Maybe you are good at
that - you certainly claim to be, and I have no evidence to the contrary.

But in other fields, you are highly ignorant. And you then fill in the
gaps in your knowledge with any old crap that springs to mind. That is
not "considering the options", it is idiocy.

Everyone is highly ignorant about this virus.

No. Some people - like you - are so highly ignorant you don't even
understand what you are ignorant about. Others know a great deal more.
No one knows everything, and there are lots of aspects that no one yet
knows.

Various experts and Top
Scientists with Computer Simulations are making wildly different
projections. They would be hilarious if things weren't so serious.
Test density is increasing exponentially but case rates are not
adjusted. My guesses are as good as anybody else' now.


It is that last part it is so absurd. No, your guesses are /not/ as
good as anybody else's. That is the whole point of letting experts make
/qualified/ guesses. When there is a gap in scientific knowledge, that
does /not/ mean that any twit with an imagination and no common sense
can fill in that gap.

System dynamics and waveforms and measurement and problem solving are
my life, and not always electronics. We don't just design electronics,
we manufacture and sell it. The patterns here are interesting. The
dynamics could well be similar to 1918. Or to the usual winter cold.


If you are scientific about your electronics design, you'll understand
the concepts of interpolation and extrapolation.

Yes, I have been told that I don't understand exponential growth.

These are valid ways

of estimating a gap in your data, when there is enough known data to
form a reasonable hypothesis of the pattern. An entirely /unreasonable/
way would be to ask someone who hasn't seen any of the known data to
pick a number. Yet that is what you seem to be espousing in other fields.

It's a discussion group. You seem to say that no-one is allowed to
have an opinion or an observation unless they are "an expert."

What's real is that people who need evaluations and surgeries can't
get into empty hospitals. There's a front-page article in today's SF
Chron about a guy who was scheduled for brain surgery, but now doesn't
know when it might happen.


Of course that's a problem. That is one of the reasons for wanting a
lockdown, so that the Covid-19 pandemic does not overwhelm the medical
services.

We have hospitals that are a few per cent full.

About 600K people die of cancer in the US every year, out of about 1.8
million disgnosies. They are not being diagnosed now. Do the math.


Have you any idea of how many people would die if there wasn't a
lockdown?

No, I don't. Neither do you. The lockdown may well result in net
deaths. What happens when the lockdown is over and people emerge? Are
they somehow immune from being isolated?

How long do we lock down until every single virus is gone?

How do we feed and take care of people meanwhile?

Vastly more than those 600K people would die directly from
Covid-19 - it would likely be millions (we are just talking about the
USA here). Common estimates (and they are only estimates) are that you
need 60% infected to get herd immunity (though there is now severe doubt
about how immunity you get after recovery). And with a totally
overwhelmed health service, between 5% and 10% will die. So without
working hard to limit the spread of this virus, it would be unsurprising
to see 10 to 20 million people die in the USA alone.

Let's remember that number for later.

Looks like the USA may be near peak at a bit under 2000 deaths per
day. If it is as awful as people say, it will run out of old people to
kill.

And then a lot more than 600K would die of cancer, because so many
health carers have died too.

The damage to our economies is not in doubt either.


No.

Again, people who don't like my thoughts respond with personal
insults, not reasoned discussion. Insults are all they have.


People have tried reasoned discussion, but it is not really possible
with you. It only makes sense to have a rational discussion with a
rational person.

Nothing but insults. That's sad.

My only objection to stupid insults is that it shows that one more
member of the group is unwilling to think. We need more people capable
of calm reasoning and intelligent discussion.


You are usually calm - I'll give you that. Reasoning and intelligent?
No, that is not you. (Or to be fairer and more accurate, you don't
apply reason and intelligence to thinking about many of the topics
discussed in s.e.d. Perhaps you could, but you don't.)

I do start threads about electronics. This crowd seems uninterested in
electronics.


I'm not terribly interested in analogue electronics. I'm not much good
at it - it's simply not my field. I like digital electronics, because
it's easy, and my main job is programming microcontrollers. So I
sometimes join in threads if these turn up.

Oh, a coder. Code does not involve science or causality, and
especially doesn't require any understanding of math or system
dynamics.

I have heard that English majors make good coders. Maybe because they
type well.


--

John Larkin Highland Technology, Inc
picosecond timing precision measurement

jlarkin att highlandtechnology dott com
http://www.highlandtechnology.com