EE rant...

[Dan Purgert]

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Hash: SHA512

On 2023-01-06, Don Y wrote:

On 1/5/2023 4:38 PM, Dan Purgert wrote:
On 2023-01-05, Don Y wrote:
On 1/5/2023 10:29 AM, Dan Purgert wrote:

Don\'t be dismissive of them. Each algorithm has different characteristics
and cost-benefits, depending on what you are trying to sort. E.g., adding
one item to a sorted list is different than sorting a \"random\" list.

Oh, I\'m not. But I meant the _writing_ of one of those algorithms \"in
the real world\" is generally not done -- a parallel to your \"nobody
builds a powersupply\".

They are nice, simple interview questions to see if the applicant
has any *theory* instead of just \"coding experience\". (No need to
have him code the algorithm, just *describe* it and tell me where
it shines/suffers)

Yeah, I always hated getting those thrown at me for jobs that weren\'t
programming-centric. I get the concept / point of the question, but
you\'re hiring me to manage tapes / backup schedules (for example).

They are great exemplars for showing the *cost* of different approaches
(sort is sort is sort, right? so, wouldn\'t you opt for the cheapest??)

Cheapest is likely also the least efficient in terms of \"time\", and
nobody these days is gonna care if you took another 200 MiB of RAM to
get something done if it \"feels\" faster for the end user.

Granted, there is a balance point you have to \"engineer\" to.

Knuth wrote a series of tomes covering most of the \"basic\" algorithms.
Surprisingly, much software is just a rearranging of these core
algorithms in different combinations.

TAOCP is on my amazon wishlist ...

You may be able to find a used copy. OTOH, many folks are content to
have them on their bookshelves, even if not referenced.

Yeah, AMZN has used from time to time. It\'s more of a reminder to check
in on those prices.

[...]
Ha! Perseverance pays off!

https://en.wikipedia.org/wiki/Raytheon_Lectron

Ouch! Hadn\'t realized it was that long ago (not sold since 1969)

oof, a bit before my time. The kiddos here love their elenco (?)
snap-together circuit toy.

[...]
Quite so. But C doesn\'t really have much more in the \'aha\' space for

C can be interesting if you start trying to adopt different
programming practices. E.g., most of my current project is coded
in C but is entirely object-based. And, objects are referenced by
something akin to file handles.

Sure, but there\'s only so much one can do on a micro, especially one
that doesn\'t have much (anything) in the way of \"external connectivity\"
(okay, sure, someone could _take_ it, but meh)

There are all sorts of different processors available. You just
have to decide what features you want and what price you are
willing to pay.

Oops, I cut out the wrong paragraph there. The response was _supposed_
to be referencing your comments regarding the compiler writing better /
less-exploitable assembly; not your object-oriented C.

As for \"all sorts\" -- yeah, I\'m making my way into some of the new AVR
0- / 1- / 2-series chips (e.g. the 404/414/1624) as well as their DA and
DB series of megas...

Even \"dirt cheap\" MCUs can have interesting applications.
E.g., WRITE a program to read an A/DC to determine the
current \"output voltage\" and, based on that value, decide
whether or not to turn on a pass transistor (feeding a
choke) and for how long. Presto! You have your own
switching power supply -- implemented in software!

I was looking into something like that the other day, actually. Looks
like I\'d need to wrap my own inductor (eep), but otherwise, I think I
have the necessary other stuff.

But need to do a little more research to verify that.

(you can even design it so the processor is *powered*
by that power supply -- that *it* is actively regulating!)

[Of course, a bug in your code can fry your processor! :> ]

(poof) \"oops\". Learning by mistakes is still learning (but I\'d rather
learn from someone else\'s mistake )


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|_|O|_|
|_|_|O| Github: https://github.com/dpurgert
|O|O|O| PGP: DDAB 23FB 19FA 7D85 1CC1 E067 6D65 70E5 4CE7 2860

 

[Dan Purgert]

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Hash: SHA512

On 2023-01-06, Don Y wrote:

On 1/5/2023 4:38 PM, Dan Purgert wrote:
On 2023-01-05, Don Y wrote:
On 1/5/2023 10:29 AM, Dan Purgert wrote:

Don\'t be dismissive of them. Each algorithm has different characteristics
and cost-benefits, depending on what you are trying to sort. E.g., adding
one item to a sorted list is different than sorting a \"random\" list.

Oh, I\'m not. But I meant the _writing_ of one of those algorithms \"in
the real world\" is generally not done -- a parallel to your \"nobody
builds a powersupply\".

They are nice, simple interview questions to see if the applicant
has any *theory* instead of just \"coding experience\". (No need to
have him code the algorithm, just *describe* it and tell me where
it shines/suffers)

Yeah, I always hated getting those thrown at me for jobs that weren\'t
programming-centric. I get the concept / point of the question, but
you\'re hiring me to manage tapes / backup schedules (for example).

They are great exemplars for showing the *cost* of different approaches
(sort is sort is sort, right? so, wouldn\'t you opt for the cheapest??)

Cheapest is likely also the least efficient in terms of \"time\", and
nobody these days is gonna care if you took another 200 MiB of RAM to
get something done if it \"feels\" faster for the end user.

Granted, there is a balance point you have to \"engineer\" to.

Knuth wrote a series of tomes covering most of the \"basic\" algorithms.
Surprisingly, much software is just a rearranging of these core
algorithms in different combinations.

TAOCP is on my amazon wishlist ...

You may be able to find a used copy. OTOH, many folks are content to
have them on their bookshelves, even if not referenced.

Yeah, AMZN has used from time to time. It\'s more of a reminder to check
in on those prices.

[...]
Ha! Perseverance pays off!

https://en.wikipedia.org/wiki/Raytheon_Lectron

Ouch! Hadn\'t realized it was that long ago (not sold since 1969)

oof, a bit before my time. The kiddos here love their elenco (?)
snap-together circuit toy.

[...]
Quite so. But C doesn\'t really have much more in the \'aha\' space for

C can be interesting if you start trying to adopt different
programming practices. E.g., most of my current project is coded
in C but is entirely object-based. And, objects are referenced by
something akin to file handles.

Sure, but there\'s only so much one can do on a micro, especially one
that doesn\'t have much (anything) in the way of \"external connectivity\"
(okay, sure, someone could _take_ it, but meh)

There are all sorts of different processors available. You just
have to decide what features you want and what price you are
willing to pay.

Oops, I cut out the wrong paragraph there. The response was _supposed_
to be referencing your comments regarding the compiler writing better /
less-exploitable assembly; not your object-oriented C.

As for \"all sorts\" -- yeah, I\'m making my way into some of the new AVR
0- / 1- / 2-series chips (e.g. the 404/414/1624) as well as their DA and
DB series of megas...

Even \"dirt cheap\" MCUs can have interesting applications.
E.g., WRITE a program to read an A/DC to determine the
current \"output voltage\" and, based on that value, decide
whether or not to turn on a pass transistor (feeding a
choke) and for how long. Presto! You have your own
switching power supply -- implemented in software!

I was looking into something like that the other day, actually. Looks
like I\'d need to wrap my own inductor (eep), but otherwise, I think I
have the necessary other stuff.

But need to do a little more research to verify that.

(you can even design it so the processor is *powered*
by that power supply -- that *it* is actively regulating!)

[Of course, a bug in your code can fry your processor! :> ]

(poof) \"oops\". Learning by mistakes is still learning (but I\'d rather
learn from someone else\'s mistake )


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--
|_|O|_|
|_|_|O| Github: https://github.com/dpurgert
|O|O|O| PGP: DDAB 23FB 19FA 7D85 1CC1 E067 6D65 70E5 4CE7 2860

 

[Dan Purgert]

-----BEGIN PGP SIGNED MESSAGE-----
Hash: SHA512

On 2023-01-06, Don Y wrote:

On 1/5/2023 4:38 PM, Dan Purgert wrote:
On 2023-01-05, Don Y wrote:
On 1/5/2023 10:29 AM, Dan Purgert wrote:

Don\'t be dismissive of them. Each algorithm has different characteristics
and cost-benefits, depending on what you are trying to sort. E.g., adding
one item to a sorted list is different than sorting a \"random\" list.

Oh, I\'m not. But I meant the _writing_ of one of those algorithms \"in
the real world\" is generally not done -- a parallel to your \"nobody
builds a powersupply\".

They are nice, simple interview questions to see if the applicant
has any *theory* instead of just \"coding experience\". (No need to
have him code the algorithm, just *describe* it and tell me where
it shines/suffers)

Yeah, I always hated getting those thrown at me for jobs that weren\'t
programming-centric. I get the concept / point of the question, but
you\'re hiring me to manage tapes / backup schedules (for example).

They are great exemplars for showing the *cost* of different approaches
(sort is sort is sort, right? so, wouldn\'t you opt for the cheapest??)

Cheapest is likely also the least efficient in terms of \"time\", and
nobody these days is gonna care if you took another 200 MiB of RAM to
get something done if it \"feels\" faster for the end user.

Granted, there is a balance point you have to \"engineer\" to.

Knuth wrote a series of tomes covering most of the \"basic\" algorithms.
Surprisingly, much software is just a rearranging of these core
algorithms in different combinations.

TAOCP is on my amazon wishlist ...

You may be able to find a used copy. OTOH, many folks are content to
have them on their bookshelves, even if not referenced.

Yeah, AMZN has used from time to time. It\'s more of a reminder to check
in on those prices.

[...]
Ha! Perseverance pays off!

https://en.wikipedia.org/wiki/Raytheon_Lectron

Ouch! Hadn\'t realized it was that long ago (not sold since 1969)

oof, a bit before my time. The kiddos here love their elenco (?)
snap-together circuit toy.

[...]
Quite so. But C doesn\'t really have much more in the \'aha\' space for

C can be interesting if you start trying to adopt different
programming practices. E.g., most of my current project is coded
in C but is entirely object-based. And, objects are referenced by
something akin to file handles.

Sure, but there\'s only so much one can do on a micro, especially one
that doesn\'t have much (anything) in the way of \"external connectivity\"
(okay, sure, someone could _take_ it, but meh)

There are all sorts of different processors available. You just
have to decide what features you want and what price you are
willing to pay.

Oops, I cut out the wrong paragraph there. The response was _supposed_
to be referencing your comments regarding the compiler writing better /
less-exploitable assembly; not your object-oriented C.

As for \"all sorts\" -- yeah, I\'m making my way into some of the new AVR
0- / 1- / 2-series chips (e.g. the 404/414/1624) as well as their DA and
DB series of megas...

Even \"dirt cheap\" MCUs can have interesting applications.
E.g., WRITE a program to read an A/DC to determine the
current \"output voltage\" and, based on that value, decide
whether or not to turn on a pass transistor (feeding a
choke) and for how long. Presto! You have your own
switching power supply -- implemented in software!

I was looking into something like that the other day, actually. Looks
like I\'d need to wrap my own inductor (eep), but otherwise, I think I
have the necessary other stuff.

But need to do a little more research to verify that.

(you can even design it so the processor is *powered*
by that power supply -- that *it* is actively regulating!)

[Of course, a bug in your code can fry your processor! :> ]

(poof) \"oops\". Learning by mistakes is still learning (but I\'d rather
learn from someone else\'s mistake )


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|_|O|_|
|_|_|O| Github: https://github.com/dpurgert
|O|O|O| PGP: DDAB 23FB 19FA 7D85 1CC1 E067 6D65 70E5 4CE7 2860

 

[John Larkin]

On Tue, 3 Jan 2023 10:15:01 -0700, Don Y <blockedofcourse@foo.invalid>
wrote:

On 1/3/2023 8:06 AM, mmm wrote:
usually we ( in Italy ) don\'t use cylindrical pre-made \"cannelloni\" but sheet
of pasta, for dry pasta you need to pre-boil tha pasta, for fresh egg-based
pasta ( as the recipe ) is not needed

+1

If you\'re not making the pasta, as well, why bother?

(personally, I\'d prefer cavatelli -- ideally, with chestnut flour. but,
a lot of work and a pound barely feeds one!)

P.S. : for the stuffing follow your personal taste

just some ideas :

fresh cheese ( ricotta ) and/or bechamel and
1) spinach
2) mushrooms
3) minced meat ( or ragu\' )
4) 1+3 ;-)

Spinach and VERY small pieces of potato (like in
scacciata)

with some effort the recipes can even be done \"vegan\"

I think some would object to the egg.

Q: what is a \"packet\" of vanilla? I want to make some
biscotti al latte and each Rx refers to vanilla in that
quantity (here, we would measure volumetrically)

Mo makes fabulous biscotti - it takes two days - and I\'ll see if I can
post her recipe.

I like them chocolate dipped.

 

[John Larkin]

On Tue, 3 Jan 2023 10:15:01 -0700, Don Y <blockedofcourse@foo.invalid>
wrote:

On 1/3/2023 8:06 AM, mmm wrote:
usually we ( in Italy ) don\'t use cylindrical pre-made \"cannelloni\" but sheet
of pasta, for dry pasta you need to pre-boil tha pasta, for fresh egg-based
pasta ( as the recipe ) is not needed

+1

If you\'re not making the pasta, as well, why bother?

(personally, I\'d prefer cavatelli -- ideally, with chestnut flour. but,
a lot of work and a pound barely feeds one!)

P.S. : for the stuffing follow your personal taste

just some ideas :

fresh cheese ( ricotta ) and/or bechamel and
1) spinach
2) mushrooms
3) minced meat ( or ragu\' )
4) 1+3 ;-)

Spinach and VERY small pieces of potato (like in
scacciata)

with some effort the recipes can even be done \"vegan\"

I think some would object to the egg.

Q: what is a \"packet\" of vanilla? I want to make some
biscotti al latte and each Rx refers to vanilla in that
quantity (here, we would measure volumetrically)

Mo makes fabulous biscotti - it takes two days - and I\'ll see if I can
post her recipe.

I like them chocolate dipped.

 

[John Larkin]

On Tue, 3 Jan 2023 10:15:01 -0700, Don Y <blockedofcourse@foo.invalid>
wrote:

On 1/3/2023 8:06 AM, mmm wrote:
usually we ( in Italy ) don\'t use cylindrical pre-made \"cannelloni\" but sheet
of pasta, for dry pasta you need to pre-boil tha pasta, for fresh egg-based
pasta ( as the recipe ) is not needed

+1

If you\'re not making the pasta, as well, why bother?

(personally, I\'d prefer cavatelli -- ideally, with chestnut flour. but,
a lot of work and a pound barely feeds one!)

P.S. : for the stuffing follow your personal taste

just some ideas :

fresh cheese ( ricotta ) and/or bechamel and
1) spinach
2) mushrooms
3) minced meat ( or ragu\' )
4) 1+3 ;-)

Spinach and VERY small pieces of potato (like in
scacciata)

with some effort the recipes can even be done \"vegan\"

I think some would object to the egg.

Q: what is a \"packet\" of vanilla? I want to make some
biscotti al latte and each Rx refers to vanilla in that
quantity (here, we would measure volumetrically)

Mo makes fabulous biscotti - it takes two days - and I\'ll see if I can
post her recipe.

I like them chocolate dipped.

 

[Don]

Lasse Langwadt Christensen wrote:

skrev Don Y:
Lasse Langwadt Christensen wrote:
skrev Don Y:
bitrex wrote:
And then people complain the US doesn\'t make electronics anymore. Challenging
programs with a high washout rate AND it doesn\'t pay too good? Wow hard to
believe everyone isn\'t jumping on that one, lol
Nowadays, even \"makers\" don\'t *make* electronics. They just buy
modules and write some code. Modern packages are just too tedious
for hobbyists; you want successes to encourage your efforts, not
failures.

modern packages are not really an issue when places like JLCPCB
does multilayer pcbs and assembly for the price of a cup of coffee
You still have to layout the board *and* be able to troubleshoot
it when it doesn\'t behave the way you expect.

For that same cup of coffee, you can buy a \"module\" and solder wires
to \"pins/headers\".

And, have a development environment, premade.

I\'ve got to layout an SDR front-end. How many iterations before
I get the noise floor down where I want it? OTOH, I can *buy*
a predesigned board and just concentrate on coding the radio.
(but the predesigned board won\'t meet my cost targets or the
packaging form factor)

a pile of boards and wire in a Tupperware container?

Seen here stacked: a WRT-54g and WAP-54g were interlinked and
sealed inside Tupperware there was only a power lead.

<https://www.qsl.net/kj6dzb/HAM/Wierless%20Hardwere.html>

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[Don]

Lasse Langwadt Christensen wrote:

skrev Don Y:
Lasse Langwadt Christensen wrote:
skrev Don Y:
bitrex wrote:
And then people complain the US doesn\'t make electronics anymore. Challenging
programs with a high washout rate AND it doesn\'t pay too good? Wow hard to
believe everyone isn\'t jumping on that one, lol
Nowadays, even \"makers\" don\'t *make* electronics. They just buy
modules and write some code. Modern packages are just too tedious
for hobbyists; you want successes to encourage your efforts, not
failures.

modern packages are not really an issue when places like JLCPCB
does multilayer pcbs and assembly for the price of a cup of coffee
You still have to layout the board *and* be able to troubleshoot
it when it doesn\'t behave the way you expect.

For that same cup of coffee, you can buy a \"module\" and solder wires
to \"pins/headers\".

And, have a development environment, premade.

I\'ve got to layout an SDR front-end. How many iterations before
I get the noise floor down where I want it? OTOH, I can *buy*
a predesigned board and just concentrate on coding the radio.
(but the predesigned board won\'t meet my cost targets or the
packaging form factor)

a pile of boards and wire in a Tupperware container?

Seen here stacked: a WRT-54g and WAP-54g were interlinked and
sealed inside Tupperware there was only a power lead.

<https://www.qsl.net/kj6dzb/HAM/Wierless%20Hardwere.html>

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[Don]

Lasse Langwadt Christensen wrote:

skrev Don Y:
Lasse Langwadt Christensen wrote:
skrev Don Y:
bitrex wrote:
And then people complain the US doesn\'t make electronics anymore. Challenging
programs with a high washout rate AND it doesn\'t pay too good? Wow hard to
believe everyone isn\'t jumping on that one, lol
Nowadays, even \"makers\" don\'t *make* electronics. They just buy
modules and write some code. Modern packages are just too tedious
for hobbyists; you want successes to encourage your efforts, not
failures.

modern packages are not really an issue when places like JLCPCB
does multilayer pcbs and assembly for the price of a cup of coffee
You still have to layout the board *and* be able to troubleshoot
it when it doesn\'t behave the way you expect.

For that same cup of coffee, you can buy a \"module\" and solder wires
to \"pins/headers\".

And, have a development environment, premade.

I\'ve got to layout an SDR front-end. How many iterations before
I get the noise floor down where I want it? OTOH, I can *buy*
a predesigned board and just concentrate on coding the radio.
(but the predesigned board won\'t meet my cost targets or the
packaging form factor)

a pile of boards and wire in a Tupperware container?

Seen here stacked: a WRT-54g and WAP-54g were interlinked and
sealed inside Tupperware there was only a power lead.

<https://www.qsl.net/kj6dzb/HAM/Wierless%20Hardwere.html>

Danke,

--
Don, KB7RPU, https://www.qsl.net/kb7rpu
There was a young lady named Bright Whose speed was far faster than light;
She set out one day In a relative way And returned on the previous night.

 

[Fred Bloggs]

On Saturday, December 31, 2022 at 1:19:58 PM UTC-5, Ed Lee wrote:

But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter.

The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it\'s just same design with new label, when they got enough reports/complaints.

I am wondering if it\'s worth picking up some of the older 1000V models off ebay.

You blew out some nominal protection like this:

https://www.vishay.com/docs/29072/ptccl.pdf

This is a quiescently low ohm resistor in series with measurement input. Schematics show a voltage clamp shunt to COM after the PTC.

If the meter comes on and presents a normal display but doesn\'t produce any readings, your PTC is open. If the meter is dead and produces a haywire or no display, you\'ve blown their processor chip, which means the voltage clamp failed, was missing, or never worked. Apparently the PTC will fail from overvoltage. It should fail open. Hard to imagine the voltage clamp being overstressed. The PTC is easy to spot. You might take a look at it. And if an issue with the CenTech brand, you might buy a handful and replace the garbage in your working meters with better PTCs.

 

[Fred Bloggs]

On Saturday, December 31, 2022 at 1:19:58 PM UTC-5, Ed Lee wrote:

But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter.

The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it\'s just same design with new label, when they got enough reports/complaints.

I am wondering if it\'s worth picking up some of the older 1000V models off ebay.

You blew out some nominal protection like this:

https://www.vishay.com/docs/29072/ptccl.pdf

This is a quiescently low ohm resistor in series with measurement input. Schematics show a voltage clamp shunt to COM after the PTC.

If the meter comes on and presents a normal display but doesn\'t produce any readings, your PTC is open. If the meter is dead and produces a haywire or no display, you\'ve blown their processor chip, which means the voltage clamp failed, was missing, or never worked. Apparently the PTC will fail from overvoltage. It should fail open. Hard to imagine the voltage clamp being overstressed. The PTC is easy to spot. You might take a look at it. And if an issue with the CenTech brand, you might buy a handful and replace the garbage in your working meters with better PTCs.

 

[Fred Bloggs]

On Saturday, December 31, 2022 at 1:19:58 PM UTC-5, Ed Lee wrote:

But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter.

The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it\'s just same design with new label, when they got enough reports/complaints.

I am wondering if it\'s worth picking up some of the older 1000V models off ebay.

You blew out some nominal protection like this:

https://www.vishay.com/docs/29072/ptccl.pdf

This is a quiescently low ohm resistor in series with measurement input. Schematics show a voltage clamp shunt to COM after the PTC.

If the meter comes on and presents a normal display but doesn\'t produce any readings, your PTC is open. If the meter is dead and produces a haywire or no display, you\'ve blown their processor chip, which means the voltage clamp failed, was missing, or never worked. Apparently the PTC will fail from overvoltage. It should fail open. Hard to imagine the voltage clamp being overstressed. The PTC is easy to spot. You might take a look at it. And if an issue with the CenTech brand, you might buy a handful and replace the garbage in your working meters with better PTCs.

 

[Phil Hobbs]

bitrex wrote:

On 1/4/2023 11:46 AM, Phil Hobbs wrote:
bitrex wrote:
On 1/3/2023 7:30 PM, Phil Hobbs wrote:
RichD wrote:
On January 1,  John Larkin wrote:
https://www.theregister.com/2022/07/18/electrical_engineers_extinction/?td=rt-9cp

I\'ve been thinking for some time now that EE schools don\'t turn out
people who like electricity, but maker culture might.

I advise younguns against an engineering degree, it\'s
over-specialized,
and obsolete in 5 years.

Only if you get sucked into spending all your time on the flavor of
the month.  People who spend their time in school learning
fundamental things that are hard to master on your own (math,
mostly) and then pick up the other stuff as they go along don\'t get
obsolete.  That\'s not difficult to do in your average EE program
even today, AFAICT. Signals and systems, electrodynamics, solid
state theory, and a bit of quantum are all good things to know.

Spending all your time in school programming in Javascript or VHDL
or memorizing compliance requirements is not a good career move for
an EE.

I tell them to get a physics education.  Study hard.  Then you have
the
tools to do anything you want.

Physicists turn up everywhere, it\'s true.  Folks with bachelor\'s
degrees in physics can do most kinds of engineering, provided
they\'re willing to bone up on the specifics.  Of course there are
some who assume they know everything and just bull ahead till they
fail, but, well, human beings are everyplace.   Thing is, the
basic professional qualification for a physicist is a doctorate,
whereas in engineering it\'s a BSEE.

That is, first the academics, then the vocational training.

I agree that knowing the fundamentals cold is very important.
However, (a) physics isn\'t for everyone, by a long chalk; and (b)
there\'s a glorious intellectual heritage in engineering, so calling
it \'vocational training\' is pejorative.

Cheers

Phil \"Intermediate energy state\" Hobbs


Advanced engineering mathematics:

https://www.ebay.com/itm/194964206310

Which is pretty advanced, I don\'t know how many BS-type EEs know
about the orthogonality of Bessel functions, or regularly use contour
integration for anything.

You need to be able to do contour integration in a whole lot of
signals and systems.  For instance, the proof that instability in a
linear system is the same as acausal behavior depends on it.

The exp(i omega t) in the Fourier integral means that you have to
close the contour in one half plane for positive time and the other
for negative time.  If there are any poles inside the negative-time
contour, you get acausal response and exponential growth.   (A very
pretty result first proved by E. C. Titchmarsh, I think.)

But not as advanced as \"Advanced Mathematical Methods for Scientists
& Engineers\", which is largely about perturbation methods, boundary
layer theory, and WKB approximations. Sounds fun I guess, I just got
a used copy from Amazon for $8

That\'s Bender & Orszag, right?  By far my favorite math book of all
time.  I just _love_ that one.  The prof for my (first year grad)
asymptotic methods class was a former EE (Stephanos Venakides, may his
tribe increase).  That helped a lot.  Math classes taught by
mathematicians tend to be dry, because they regard the subject like
philosophy, whereas to a scientist or engineer, math is a technology
of thought.

BITD Arfken\'s \"Mathematical Methods for Physicists\" was one of the
standard math books for undergraduate physics, along with Levenson &
Redheffer\'s complex variables book, Boyce & di Prima on ODEs, Carrier
& Pearson for PDEs, and something on linear algebra.  My linear alg
class was taught out of Schaum\'s Outline, believe it or not--super
cheap and actually a pretty good book.  Oh, and a little book on the
theoretical side of calculus, so that you can prove theorems and stuff
if you need to.

Yes that\'s the one. I don\'t understand much beyond part II, maybe
someday, but the material about ODEs, difference equations, and
asymptotic expansions is worth the price of admission alone.

Fourier analysis, perturbation theory, asymptotic methods, cluster
expansions, tensor calculus, and Feynman path integrals were all
taught in physics classes.  I took four EE classes in grad
school--Tony Siegman on lasers, Steve Harris on nonlinear optics, and
Ron Bracewell on how to think in k-space (aka reciprocal space and
Fourier space), and Bernie Widrow on DSP.

I\'m taking an online course in statistical mechanics, it\'s pretty cool,
connecting quantum mechanics micro ---> the PVNRT macro

Yup. The power of stat mech is precisely in the asymptotics,
though--that\'s how you get the thermodynamic quantities to be properly
_extensive_. (That is, things like temperature and entropy density don\'t
depend explicitly on the N, the number of atoms in the system.)

When you go to compute the partition function for the given ensemble
(canonical for fixed N, grand canonical for variable N), one of the very
first moves is to apply a truncated Stirling asymptotic expansion for
the gamma (factorial) function.

The higher order corrections, such as the Mayer cluster expansion, are
also asymptotic.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

bitrex wrote:

On 1/4/2023 11:46 AM, Phil Hobbs wrote:
bitrex wrote:
On 1/3/2023 7:30 PM, Phil Hobbs wrote:
RichD wrote:
On January 1,  John Larkin wrote:
https://www.theregister.com/2022/07/18/electrical_engineers_extinction/?td=rt-9cp

I\'ve been thinking for some time now that EE schools don\'t turn out
people who like electricity, but maker culture might.

I advise younguns against an engineering degree, it\'s
over-specialized,
and obsolete in 5 years.

Only if you get sucked into spending all your time on the flavor of
the month.  People who spend their time in school learning
fundamental things that are hard to master on your own (math,
mostly) and then pick up the other stuff as they go along don\'t get
obsolete.  That\'s not difficult to do in your average EE program
even today, AFAICT. Signals and systems, electrodynamics, solid
state theory, and a bit of quantum are all good things to know.

Spending all your time in school programming in Javascript or VHDL
or memorizing compliance requirements is not a good career move for
an EE.

I tell them to get a physics education.  Study hard.  Then you have
the
tools to do anything you want.

Physicists turn up everywhere, it\'s true.  Folks with bachelor\'s
degrees in physics can do most kinds of engineering, provided
they\'re willing to bone up on the specifics.  Of course there are
some who assume they know everything and just bull ahead till they
fail, but, well, human beings are everyplace.   Thing is, the
basic professional qualification for a physicist is a doctorate,
whereas in engineering it\'s a BSEE.

That is, first the academics, then the vocational training.

I agree that knowing the fundamentals cold is very important.
However, (a) physics isn\'t for everyone, by a long chalk; and (b)
there\'s a glorious intellectual heritage in engineering, so calling
it \'vocational training\' is pejorative.

Cheers

Phil \"Intermediate energy state\" Hobbs


Advanced engineering mathematics:

https://www.ebay.com/itm/194964206310

Which is pretty advanced, I don\'t know how many BS-type EEs know
about the orthogonality of Bessel functions, or regularly use contour
integration for anything.

You need to be able to do contour integration in a whole lot of
signals and systems.  For instance, the proof that instability in a
linear system is the same as acausal behavior depends on it.

The exp(i omega t) in the Fourier integral means that you have to
close the contour in one half plane for positive time and the other
for negative time.  If there are any poles inside the negative-time
contour, you get acausal response and exponential growth.   (A very
pretty result first proved by E. C. Titchmarsh, I think.)

But not as advanced as \"Advanced Mathematical Methods for Scientists
& Engineers\", which is largely about perturbation methods, boundary
layer theory, and WKB approximations. Sounds fun I guess, I just got
a used copy from Amazon for $8

That\'s Bender & Orszag, right?  By far my favorite math book of all
time.  I just _love_ that one.  The prof for my (first year grad)
asymptotic methods class was a former EE (Stephanos Venakides, may his
tribe increase).  That helped a lot.  Math classes taught by
mathematicians tend to be dry, because they regard the subject like
philosophy, whereas to a scientist or engineer, math is a technology
of thought.

BITD Arfken\'s \"Mathematical Methods for Physicists\" was one of the
standard math books for undergraduate physics, along with Levenson &
Redheffer\'s complex variables book, Boyce & di Prima on ODEs, Carrier
& Pearson for PDEs, and something on linear algebra.  My linear alg
class was taught out of Schaum\'s Outline, believe it or not--super
cheap and actually a pretty good book.  Oh, and a little book on the
theoretical side of calculus, so that you can prove theorems and stuff
if you need to.

Yes that\'s the one. I don\'t understand much beyond part II, maybe
someday, but the material about ODEs, difference equations, and
asymptotic expansions is worth the price of admission alone.

Fourier analysis, perturbation theory, asymptotic methods, cluster
expansions, tensor calculus, and Feynman path integrals were all
taught in physics classes.  I took four EE classes in grad
school--Tony Siegman on lasers, Steve Harris on nonlinear optics, and
Ron Bracewell on how to think in k-space (aka reciprocal space and
Fourier space), and Bernie Widrow on DSP.

I\'m taking an online course in statistical mechanics, it\'s pretty cool,
connecting quantum mechanics micro ---> the PVNRT macro

Yup. The power of stat mech is precisely in the asymptotics,
though--that\'s how you get the thermodynamic quantities to be properly
_extensive_. (That is, things like temperature and entropy density don\'t
depend explicitly on the N, the number of atoms in the system.)

When you go to compute the partition function for the given ensemble
(canonical for fixed N, grand canonical for variable N), one of the very
first moves is to apply a truncated Stirling asymptotic expansion for
the gamma (factorial) function.

The higher order corrections, such as the Mayer cluster expansion, are
also asymptotic.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Phil Hobbs]

bitrex wrote:

On 1/4/2023 11:46 AM, Phil Hobbs wrote:
bitrex wrote:
On 1/3/2023 7:30 PM, Phil Hobbs wrote:
RichD wrote:
On January 1,  John Larkin wrote:
https://www.theregister.com/2022/07/18/electrical_engineers_extinction/?td=rt-9cp

I\'ve been thinking for some time now that EE schools don\'t turn out
people who like electricity, but maker culture might.

I advise younguns against an engineering degree, it\'s
over-specialized,
and obsolete in 5 years.

Only if you get sucked into spending all your time on the flavor of
the month.  People who spend their time in school learning
fundamental things that are hard to master on your own (math,
mostly) and then pick up the other stuff as they go along don\'t get
obsolete.  That\'s not difficult to do in your average EE program
even today, AFAICT. Signals and systems, electrodynamics, solid
state theory, and a bit of quantum are all good things to know.

Spending all your time in school programming in Javascript or VHDL
or memorizing compliance requirements is not a good career move for
an EE.

I tell them to get a physics education.  Study hard.  Then you have
the
tools to do anything you want.

Physicists turn up everywhere, it\'s true.  Folks with bachelor\'s
degrees in physics can do most kinds of engineering, provided
they\'re willing to bone up on the specifics.  Of course there are
some who assume they know everything and just bull ahead till they
fail, but, well, human beings are everyplace.   Thing is, the
basic professional qualification for a physicist is a doctorate,
whereas in engineering it\'s a BSEE.

That is, first the academics, then the vocational training.

I agree that knowing the fundamentals cold is very important.
However, (a) physics isn\'t for everyone, by a long chalk; and (b)
there\'s a glorious intellectual heritage in engineering, so calling
it \'vocational training\' is pejorative.

Cheers

Phil \"Intermediate energy state\" Hobbs


Advanced engineering mathematics:

https://www.ebay.com/itm/194964206310

Which is pretty advanced, I don\'t know how many BS-type EEs know
about the orthogonality of Bessel functions, or regularly use contour
integration for anything.

You need to be able to do contour integration in a whole lot of
signals and systems.  For instance, the proof that instability in a
linear system is the same as acausal behavior depends on it.

The exp(i omega t) in the Fourier integral means that you have to
close the contour in one half plane for positive time and the other
for negative time.  If there are any poles inside the negative-time
contour, you get acausal response and exponential growth.   (A very
pretty result first proved by E. C. Titchmarsh, I think.)

But not as advanced as \"Advanced Mathematical Methods for Scientists
& Engineers\", which is largely about perturbation methods, boundary
layer theory, and WKB approximations. Sounds fun I guess, I just got
a used copy from Amazon for $8

That\'s Bender & Orszag, right?  By far my favorite math book of all
time.  I just _love_ that one.  The prof for my (first year grad)
asymptotic methods class was a former EE (Stephanos Venakides, may his
tribe increase).  That helped a lot.  Math classes taught by
mathematicians tend to be dry, because they regard the subject like
philosophy, whereas to a scientist or engineer, math is a technology
of thought.

BITD Arfken\'s \"Mathematical Methods for Physicists\" was one of the
standard math books for undergraduate physics, along with Levenson &
Redheffer\'s complex variables book, Boyce & di Prima on ODEs, Carrier
& Pearson for PDEs, and something on linear algebra.  My linear alg
class was taught out of Schaum\'s Outline, believe it or not--super
cheap and actually a pretty good book.  Oh, and a little book on the
theoretical side of calculus, so that you can prove theorems and stuff
if you need to.

Yes that\'s the one. I don\'t understand much beyond part II, maybe
someday, but the material about ODEs, difference equations, and
asymptotic expansions is worth the price of admission alone.

Fourier analysis, perturbation theory, asymptotic methods, cluster
expansions, tensor calculus, and Feynman path integrals were all
taught in physics classes.  I took four EE classes in grad
school--Tony Siegman on lasers, Steve Harris on nonlinear optics, and
Ron Bracewell on how to think in k-space (aka reciprocal space and
Fourier space), and Bernie Widrow on DSP.

I\'m taking an online course in statistical mechanics, it\'s pretty cool,
connecting quantum mechanics micro ---> the PVNRT macro

Yup. The power of stat mech is precisely in the asymptotics,
though--that\'s how you get the thermodynamic quantities to be properly
_extensive_. (That is, things like temperature and entropy density don\'t
depend explicitly on the N, the number of atoms in the system.)

When you go to compute the partition function for the given ensemble
(canonical for fixed N, grand canonical for variable N), one of the very
first moves is to apply a truncated Stirling asymptotic expansion for
the gamma (factorial) function.

The higher order corrections, such as the Mayer cluster expansion, are
also asymptotic.

Cheers

Phil Hobbs

--
Dr Philip C D Hobbs
Principal Consultant
ElectroOptical Innovations LLC / Hobbs ElectroOptics
Optics, Electro-optics, Photonics, Analog Electronics
Briarcliff Manor NY 10510

http://electrooptical.net
http://hobbs-eo.com

 

[Les Cargill]

John Larkin wrote:

On Tue, 3 Jan 2023 15:59:38 -0800 (PST), RichD
r_delaney2001@yahoo.com> wrote:

On January 1, John Larkin wrote:
https://www.theregister.com/2022/07/18/electrical_engineers_extinction/?td=rt-9cp
I\'ve been thinking for some time now that EE schools don\'t turn out
people who like electricity, but maker culture might.

I advise younguns against an engineering degree, it\'s over-specialized,
and obsolete in 5 years.

The world will always need engineers.

And why should an engineer get obsolete? One fun thing about
engineering is that it keeps changing, so we get new toys and new
tools. The fundamentals don\'t change.



I tell them to get a physics education. Study hard. Then you have the
tools to do anything you want.

That is, first the academics, then the vocational training.

What sorts of careers do physicists have these days? I mean, aside
from teaching physics.

I taught one the very lowest level basics of document management
a few months back. He\'ll go far. He declined to learn C++ but
is a hand at MATLAB. He won\'t need it; he\'s already in a governance-
design position.

<snip>
--
Les Cargill

 

[Les Cargill]

John Larkin wrote:

On Tue, 3 Jan 2023 15:59:38 -0800 (PST), RichD
r_delaney2001@yahoo.com> wrote:

On January 1, John Larkin wrote:
https://www.theregister.com/2022/07/18/electrical_engineers_extinction/?td=rt-9cp
I\'ve been thinking for some time now that EE schools don\'t turn out
people who like electricity, but maker culture might.

I advise younguns against an engineering degree, it\'s over-specialized,
and obsolete in 5 years.

The world will always need engineers.

And why should an engineer get obsolete? One fun thing about
engineering is that it keeps changing, so we get new toys and new
tools. The fundamentals don\'t change.



I tell them to get a physics education. Study hard. Then you have the
tools to do anything you want.

That is, first the academics, then the vocational training.

What sorts of careers do physicists have these days? I mean, aside
from teaching physics.

I taught one the very lowest level basics of document management
a few months back. He\'ll go far. He declined to learn C++ but
is a hand at MATLAB. He won\'t need it; he\'s already in a governance-
design position.

<snip>
--
Les Cargill

 

[Les Cargill]

John Larkin wrote:

On Tue, 3 Jan 2023 15:59:38 -0800 (PST), RichD
r_delaney2001@yahoo.com> wrote:

On January 1, John Larkin wrote:
https://www.theregister.com/2022/07/18/electrical_engineers_extinction/?td=rt-9cp
I\'ve been thinking for some time now that EE schools don\'t turn out
people who like electricity, but maker culture might.

I advise younguns against an engineering degree, it\'s over-specialized,
and obsolete in 5 years.

The world will always need engineers.

And why should an engineer get obsolete? One fun thing about
engineering is that it keeps changing, so we get new toys and new
tools. The fundamentals don\'t change.



I tell them to get a physics education. Study hard. Then you have the
tools to do anything you want.

That is, first the academics, then the vocational training.

What sorts of careers do physicists have these days? I mean, aside
from teaching physics.

I taught one the very lowest level basics of document management
a few months back. He\'ll go far. He declined to learn C++ but
is a hand at MATLAB. He won\'t need it; he\'s already in a governance-
design position.

<snip>
--
Les Cargill

 

[server]

John Larkin <jlarkin@highlandsnipmetechnology.com> wrote:

On Sat, 7 Jan 2023 01:04:32 -0000 (UTC), antispam@math.uni.wroc.pl
wrote:

Ed Lee <edward.ming.lee@gmail.com> wrote:
But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter.

High voltage can destroy resistors, but this seem to be quite fast.

The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it\'s just same design with new label, when they got enough reports/complaints.

Lot of folks live in countries where line voltage is 230V. So 50 volts
makes a lot of difference.

I am wondering if it\'s worth picking up some of the older 1000V models off ebay.

I know nothing about CenTech meters. But I have several \"DT830B\"
meters. Available schematics shows 3 resistors in series for 1000V.
My oldest one have 2 resistors. Newest one have single resistor.
Standard miniature resistors are rated for 250V, one can get
better ones, but I doubt that one can get cheaply 1000V capable
ones. Still, meter is marked as 1000V DC, 700V AC (the same
as old meters).

They eliminated 0.2 cents worth of resistors. Ignore temperature and
voltage coefficient effects. Maybe some of that is mathed out?

Chinese product prices ratchet towards cheap, and the specs ratchet
deep into the lies region. Chinese amps and volts and per cent are
about 10:1 off from SI standards.

Well, the cheap \"DT830B\" were surprisingly accurate. I have
used 4 to measure the same voltage. IIRC the differences
were in last digit and did not exceed 2 counts. They were
bought from different sources at different times, so it
is unlikly to be the same error on all. And they agreed
with better meter. Newest ones seem to have larger
errors, but still well withing specs.

AFAICS biggest problem with cheap meters are test leads,
they tend to fail rather quickly. Second problem is
main switch, which is formed from part of PCB. It
seem to degrade with use. And failing switch can
produce all kinds of wrong results.

--
Waldek Hebisch

 

[server]

John Larkin <jlarkin@highlandsnipmetechnology.com> wrote:

On Sat, 7 Jan 2023 01:04:32 -0000 (UTC), antispam@math.uni.wroc.pl
wrote:

Ed Lee <edward.ming.lee@gmail.com> wrote:
But not immediately. I tested 400V occasionally, but couple of them died while testing 12V. I am wondering it 400V weaken the meter.

High voltage can destroy resistors, but this seem to be quite fast.

The old CenTech meters are 1000V, but the new models are 250V. Why even bother to have 50V more than the next range of 200V. Perhaps it\'s just same design with new label, when they got enough reports/complaints.

Lot of folks live in countries where line voltage is 230V. So 50 volts
makes a lot of difference.

I am wondering if it\'s worth picking up some of the older 1000V models off ebay.

I know nothing about CenTech meters. But I have several \"DT830B\"
meters. Available schematics shows 3 resistors in series for 1000V.
My oldest one have 2 resistors. Newest one have single resistor.
Standard miniature resistors are rated for 250V, one can get
better ones, but I doubt that one can get cheaply 1000V capable
ones. Still, meter is marked as 1000V DC, 700V AC (the same
as old meters).

They eliminated 0.2 cents worth of resistors. Ignore temperature and
voltage coefficient effects. Maybe some of that is mathed out?

Chinese product prices ratchet towards cheap, and the specs ratchet
deep into the lies region. Chinese amps and volts and per cent are
about 10:1 off from SI standards.

Well, the cheap \"DT830B\" were surprisingly accurate. I have
used 4 to measure the same voltage. IIRC the differences
were in last digit and did not exceed 2 counts. They were
bought from different sources at different times, so it
is unlikly to be the same error on all. And they agreed
with better meter. Newest ones seem to have larger
errors, but still well withing specs.

AFAICS biggest problem with cheap meters are test leads,
they tend to fail rather quickly. Second problem is
main switch, which is formed from part of PCB. It
seem to degrade with use. And failing switch can
produce all kinds of wrong results.

--
Waldek Hebisch