On Thursday, 15 August 2019 18:51:56 UTC+1, Winfield Hill wrote:
> tabbypurr wrote...
> > Really it's the sim that's wrong, but you can tackle
> > its shortcomings by adding in parts to the sim's input
> > so it sims more features of the real circuit.
>
> LTSpice lets you add parasitic aspects to basic parts,
> like resistors, but these are hidden on the schematic,
> so you have no idea whether the modeller made additions,
> or whether he made the right ones. I prefer seeing a
> SPICE schematic, with the parasitic parts explicitly
> showing, so you know what was taken care of, and how.
> To my mind, these aspects are up to the engineering
> doing the SPICE schematic drafting, and not up to the
> SPICE program. The LTSpice approach is bad, not good.
> So I disagree, it's not the sim that's wrong.
I think we're just using words a little differently, but agree on the principle.
NT
Reply by Tim Williams●August 16, 20192019-08-16
"Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
news:qj4bmo$s1v$2@dont-email.me...
> A port is not a node. KCL talks about _nodes_.
>
Well yeah, a port is a branch that connects nodes.
So the port currents don't go anywhere?
Tim
--
Seven Transistor Labs, LLC
Electrical Engineering Consultation and Design
Website: https://www.seventransistorlabs.com/
Reply by Kevin Aylward●August 16, 20192019-08-16
"Phil Hobbs" wrote in message news:qj4bve$uv1$1@dont-email.me...
On 8/15/19 2:56 PM, Kevin Aylward wrote:
>> "Phil Hobbs" wrote in message news:qj3t2i$941$1@dont-email.me...
>
>
>>
>> What you probably mean is that an ideal transmission line is a pure
>> delay. This means an exp(-tau.S) transfer function, which is not a
>> rational function of S.
>
>>> Kirchoff's laws do not apply to transmission lines. Current disappears
>>> into one end and emerges from the other end sometime later. The
>>> currents into the circuit nodes don't sum to zero, and neither do the
>>> voltages around loops.
>
>> Which is what you expect as transmission lines correctly account for the
>> fact the FTL is impossible, that is, it shows that signals take a finite
>> time to propagate from A to B, thus transmissions lines behave *locally*.
>> Period.
>In your dreams. Nonlocality doesn't imply FTL, whatever your Sunday
>supplement version of quantum field theory might tell you. The Boltzmann
>transport equation is also nonlocal, and that applies to your coffee cup.
>YCLIU.
Twaddle.
Your are seriously confused. The *definition* of non-locality is FTL Period.
No iffs or buts.
> We, apparently, have different definitions of locality.
>
> https://en.wikipedia.org/wiki/Principle_of_locality
>
> https://en.wikipedia.org/wiki/Faster-than-light_neutrino_anomaly
>
> Thus, to date the only accepted apparent FTL, i.e. non-local behaviour
> that I am aware of, is the statistical correlations between entangled
> particles, which cannot be used to transfer information at FTL
>
> It is inherent in transmission lines that there is delay for transfer of
> information, which is *the* fundamental property of the definition of
> locality in physics, so it is indeed interesting that there are those that
> claim the opposite.
>No, that's a particular definition in relativistic quantum field theory.
>We're talking classical E&M here.
Twaddle.
Again, your are seriously confused. The *definition* of non-locality is FTL
Period. No iffs or buts.
It has zero to do with Quantum Mechanics. You are really stepping out of
your depth here.
Locality and non-locality are terms intimately connected with the
construction of Special Relativity. Its not debatable.
I suggest you actually read the link:
https://en.wikipedia.org/wiki/Principle_of_locality
"In physics, the principle of locality states that an object is directly
influenced only by its immediate surroundings. A theory which includes the
principle of locality is said to be a "local theory". This is an alternative
to the older concept of instantaneous "action at a distance". Locality
evolved out of the field theories of classical physics. The concept is that
for an action at one point to have an influence at another point, something
in the space between those points such as a field must mediate the action.
To exert an influence, something, such as a wave or particle, must travel
through the space between the two points, carrying the influence."
Don't even try to contradict it, it would only makes you come across as an
"Einstein was wrong crank"
Classical E&M theory is a local theory, it is thus simply impossible for
transmission lines to behave non-locally. End off.
Thus Kirchhoff's Laws are nonlocal. Kirchhoff's Laws require voltages and
current information to be propagated instantaneously.
I suggest some refresher courses in physics, because you are only
embarrassing yourself.
-- Kevin Aylward
http://www.anasoft.co.uk - SuperSpice
http://www.kevinaylward.co.uk/ee/index.html
Reply by Kevin Aylward●August 16, 20192019-08-16
>"Phil Hobbs" wrote in message news:qj5rve$hkc$1@dont-email.me...
>I invite anyone here to write a system of ODEs for a circuit containing a
>transmission line.
Totally irrelevant.
Locality is defined by whether or not there is action at a distance faster
that the speed of light, not by properties of any equation. Its a physical
observational definition, not mathematical. If information is propagated
FTL, its non-local. Period.
Whatever custom definition you are using for "locality" is not one that ever
occurs in any Physics context, especially with regard to Maxwell's
Equations.
-- Kevin Aylward
http://www.anasoft.co.uk - SuperSpice
http://www.kevinaylward.co.uk/ee/index.html
Reply by Chris Jones●August 16, 20192019-08-16
On 16/08/2019 03:02, Phil Hobbs wrote:
> On 8/14/19 8:00 AM, Chris Jones wrote:
>> On 13/08/2019 00:02, Phil Hobbs wrote:
>>> On 8/12/19 9:11 AM, Chris Jones wrote:
>>>> On 10/08/2019 17:05, Phil Hobbs wrote:
>>>>> On 8/9/19 4:50 PM, Winfield Hill wrote:
>>>>>> Here's a new section I'm hoping to complete, so it can be
>>>>>> added to the x-Chapter book before it goes to the printer in
>>>>>> a few weeks. Please look it over, but don't be too harsh,
>>>>>> about its lack of mathematical vigor. It's closer to our
>>>>>> usual back-of-the envelope approach to calculations. Fixes
>>>>>> for errors, suggestions for clarification, improved accuracy,
>>>>>> and comments welcome.
>>>>>>
>>>>>> https://www.dropbox.com/s/7zl3yi789idg3s8/4x.26_Loop%20%26%20Nodal%20Analysis.pdf?dl=1
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> Nice. I like your making a virtue out of a necessity
>>>>> (hand-drawn figures). ;)
>>>>>
>>>>> One point that might be worth a footnote is that Kirchhoff's
>>>>> laws are a low-frequency approximation, applicable only when
>>>>> radiation and self-capacitance are negligible.
>>>>
>>>> If your schematic is really complete, then I think that the laws
>>>> apply usefully, at least until the point where radiation is
>>>> efficient. I am assuming here that current through parasitic
>>>> capacitances is counted just as much as if it were a current
>>>> flowing through a terminal of an intentional capacitor. If, in
>>>> your schematic and arithmetic, you leave out things like the
>>>> inductance and self-capacitance of wires, (and in difficult
>>>> cases, even the distributed capacitance at different points along
>>>> the inductance of wires), then of course the result of applying
>>>> Kirchoff's laws to the (incomplete) schematic won't predict the
>>>> behaviour of the actual construction. I suspect that radiation
>>>> could also be modelled in a way that allows Kirchoff's laws to be
>>>> applied but that the resulting schematic would be too
>>>> complicated.
>>>
>>> Nope. Transmission lines at the schematic level are non-local,
>>> i.e. you can't write a system of ODEs to describe a circuit with
>>> transmission lines or significant radiation. Kirchhoff's laws are
>>> derived from Maxwell's equations in the limit of low frequency (or
>>> alternatively, of small size for a fixed frequency).
>> I would say that that a wire on a schematic is not a valid
>> representation of a transmission line, and if necessary I would
>> approximate a transmission line as a ladder of (ideally infinitely)
>> many series inductors and shunt capacitors. Of course very many
>> components are required for this to be reasonably accurate.
>>
>> At frequencies where the number of required components is excessive,
>> I would then say that a schematic is not a good way to describe the
>> physical system.
>>> And if you have to model the circuit "in a way that allows
>>> Kirchhoff's laws to be applied", you've implicitly admitted that
>>> they don't apply to the actual circuit.
>> If by actual circuit we mean the physical object, then really I only
>> expect Maxwell's equations to describe it, and I'm not very good at
>> solving those. In a completely general sense I'm not even sure how
>> one would try to apply Kirchoff's laws to an arbitrary three
>> dimensional piece of electronics.
>
>
>>
>>> Don't get me wrong--K's equations are useful and all, but they
>>> have limits. Being a physicist, I fully recognize the usefulness
>>> of sleazy approximations, but you have to remember that that's what
>>> they are, or you'll get snookered.
>> Agreed.
>>
>> I guess I might have a rather unusual idea of what a schematic is,
>> and this might be what causes me to take issue with what you said. To
>> me, a schematic ought to be something that, when simulated (by some
>> ideal simulator!), applying Kirchoff's laws, Ohm's law, i=C.dv/dt and
>> so on, would sufficiently accurately predict the behavoiur of the
>> real system.
>>
>> To me, if the predictions are wrong, then I blame the schematic as
>> being an inaccurate representation of the system, rather than blaming
>> the equations used to simulate the behaviour of the schematic.
>> Perhaps my philosophy on this topic comes from having had the job of
>> making a schematic (sometimes pulling in netlists from field solvers)
>> in order to simulate my design as implemented in a physical product.
>> There was an expectation that I would use a circuit simulator
>> provided to me, that did try to apply Kirchoff's laws (though not
>> perfectly in the case of KCL). I did at least have the luxury that
>> the physical dimensions of the system were a tiny fraction of a
>> wavelength.
>
> Well, you're kind of using a private language there, as you say.
Perhaps yes, and it has the useful property that for my "schematics", as
far as I can tell, Kirchoff's laws do hold. Obviously I would like to
find out any situations where that isn't true, as I don't want wrong
predictions of the behaviour of a real system, but at that point I would
probably declare the drawing to be no longer a valid "schematic" of the
real system, again by my weird definition, and then I might try to fix
it. Perhaps I am alone in holding these attitudes, but they have served
me well so far.
Reply by Phil Hobbs●August 16, 20192019-08-16
On 8/15/19 4:22 PM, George Herold wrote:
> On Thursday, August 15, 2019 at 3:32:02 PM UTC-4, Phil Hobbs wrote:
>> On 8/15/19 2:56 PM, Kevin Aylward wrote:
>>>> "Phil Hobbs" wrote in message news:qj3t2i$941$1@dont-email.me...
>>>
>>>
>>>>
>>>> What you probably mean is that an ideal transmission line is a pure
>>>> delay. This means an exp(-tau.S) transfer function, which is not a
>>>> rational function of S.
>>>
>>>> Kirchoff's laws do not apply to transmission lines. Current
>>>> disappears into one end and emerges from the other end sometime
>>>> later. The currents into the circuit nodes don't sum to zero, and
>>>> neither do the voltages around loops.
>>>
>>> Which is what you expect as transmission lines correctly account for the
>>> fact the FTL is impossible, that is, it shows that signals take a finite
>>> time to propagate from A to B, thus transmissions lines behave
>>> *locally*. Period.
>>
>> In your dreams. Nonlocality doesn't imply FTL, whatever your Sunday
>> supplement version of quantum field theory might tell you. The
>> Boltzmann transport equation is also nonlocal, and that applies to your
>> coffee cup. YCLIU.
>>
>>>
>>> In contrast to Kirchoff's Laws. Those laws assume that all voltages and
>>> currents are instantaneously connected. They ignore propagation delay
>>> effects, thus Kirchoff's Laws are non-local. Period.
>>
>> You're inventing a private language to avoid being wrong in public.
>> G'wan, Kevin, you're just hitting your stride, man!
>
> Hmm, I gotta agree with Kevin, Kirchoff's laws are non-local.
> Just like Newtons law of gravity is non-local. At least that's how I understand
> how 'local' is used in physics. Non local implies action at a distance.. (again my understanding.)
>
> But then again I thought I agreed with everything you said... ?
> (Did you use the 'local' word?)
Seems like there's a sort of double vision there--you're not applying
the Kirchhoff approximation consistently.
Kirchhoff's voltage law: the sum of all voltages around any loop is
zero. (Equivalently, curl E = 0)
Kirchhoff's current law: the sum of all currents entering a node is zero.
Being consistent about the low-frequency approximation, nodes and loops
have negligible size. Otherwise you couldn't write a system of ODEs to
describe the circuit. So Kirchhoff's laws are local in the physical sense.
I invite anyone here to write a system of ODEs for a circuit containing
a transmission line.
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.nethttp://hobbs-eo.com
Reply by George Herold●August 15, 20192019-08-15
On Thursday, August 15, 2019 at 3:32:02 PM UTC-4, Phil Hobbs wrote:
> On 8/15/19 2:56 PM, Kevin Aylward wrote:
> >> "Phil Hobbs" wrote in message news:qj3t2i$941$1@dont-email.me...
> >
> >
> >>
> >> What you probably mean is that an ideal transmission line is a pure
> >> delay. This means an exp(-tau.S) transfer function, which is not a
> >> rational function of S.
> >
> >> Kirchoff's laws do not apply to transmission lines. Current
> >> disappears into one end and emerges from the other end sometime
> >> later. The currents into the circuit nodes don't sum to zero, and
> >> neither do the voltages around loops.
> >
> > Which is what you expect as transmission lines correctly account for the
> > fact the FTL is impossible, that is, it shows that signals take a finite
> > time to propagate from A to B, thus transmissions lines behave
> > *locally*. Period.
>
> In your dreams. Nonlocality doesn't imply FTL, whatever your Sunday
> supplement version of quantum field theory might tell you. The
> Boltzmann transport equation is also nonlocal, and that applies to your
> coffee cup. YCLIU.
>
> >
> > In contrast to Kirchoff's Laws. Those laws assume that all voltages and
> > currents are instantaneously connected. They ignore propagation delay
> > effects, thus Kirchoff's Laws are non-local. Period.
>
> You're inventing a private language to avoid being wrong in public.
> G'wan, Kevin, you're just hitting your stride, man!
Hmm, I gotta agree with Kevin, Kirchoff's laws are non-local.
Just like Newtons law of gravity is non-local. At least that's how I understand
how 'local' is used in physics. Non local implies action at a distance.. (again my understanding.)
But then again I thought I agreed with everything you said... ?
(Did you use the 'local' word?)
George H.
> >
> > Thus... you have the definitions backwards.
> >
> >>> Spice has to do extra stuff, as in convolution, to handle TLines. It
> >>> slows it down a tad...
> >
> >> As I said, the approximation can often be patched up by hand like that.
> >>
> >>
> >>>> inside the T-line can be modelled with PDEs (Maxwell), but circuits are
> >>>> all ODEs. The T-line has invisible internal state, so its circuit
> >>>> behaviour is nonlocal.
> >>
> >>> Not really....
> >>
> >>> "Non local" pretty much universally means FTL (faster than the speed
> >>> of light).
> >
> >> Nope. It means that the governing equations require information from
> >> more than one space-time point. All differential equations are local.
> >> Nonlocal systems need integral equations.
> >
> > We, apparently, have different definitions of locality.
> >
> > https://en.wikipedia.org/wiki/Principle_of_locality
> >
> > https://en.wikipedia.org/wiki/Faster-than-light_neutrino_anomaly
> >
> > Thus, to date the only accepted apparent FTL, i.e. non-local behaviour
> > that I am aware of, is the statistical correlations between entangled
> > particles, which cannot be used to transfer information at FTL
> >
> > It is inherent in transmission lines that there is delay for transfer of
> > information, which is *the* fundamental property of the definition of
> > locality in physics, so it is indeed interesting that there are those
> > that claim the opposite.
>
> No, that's a particular definition in relativistic quantum field theory.
> We're talking classical E&M here.
>
> 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
Reply by boB●August 15, 20192019-08-15
On Thu, 15 Aug 2019 18:01:13 GMT, Steve Wilson <no@spam.com> wrote:
>Winfield Hill <winfieldhill@yahoo.com> wrote:
>
>> tabbypurr@gmail.com wrote...
>
>>> Really it's the sim that's wrong, but you can tackle
>>> its shortcomings by adding in parts to the sim's input so it sims more
>>> features of the real circuit.
>
>> LTSpice lets you add parasitic aspects to basic parts,
>> like resistors, but these are hidden on the schematic,
>> so you have no idea whether the modeller made additions,
>> or whether he made the right ones. I prefer seeing a
>> SPICE schematic, with the parasitic parts explicitly
>> showing, so you know what was taken care of, and how.
>> To my mind, these aspects are up to the engineering
>> doing the SPICE schematic drafting, and not up to the
>> SPICE program. The LTSpice approach is bad, not good.
>> So I disagree, it's not the sim that's wrong.
>
>Where it is important, I add the parasitics externally.
>
LTspice does have some parasitics like ESR for instance that helps
keep the matrix from being ill conditioned as I understand it.
Also, there are places to add parasitics sometimes that do not take
extra compute time as it would if you added them externally.
That is why you should probably use them when available.
Reply by Phil Hobbs●August 15, 20192019-08-15
On 8/15/19 2:56 PM, Kevin Aylward wrote:
>> "Phil Hobbs" wrote in message news:qj3t2i$941$1@dont-email.me...
>
>
>>
>> What you probably mean is that an ideal transmission line is a pure
>> delay. This means an exp(-tau.S) transfer function, which is not a
>> rational function of S.
>
>> Kirchoff's laws do not apply to transmission lines. Current
>> disappears into one end and emerges from the other end sometime
>> later. The currents into the circuit nodes don't sum to zero, and
>> neither do the voltages around loops.
>
> Which is what you expect as transmission lines correctly account for the
> fact the FTL is impossible, that is, it shows that signals take a finite
> time to propagate from A to B, thus transmissions lines behave
> *locally*. Period.
In your dreams. Nonlocality doesn't imply FTL, whatever your Sunday
supplement version of quantum field theory might tell you. The
Boltzmann transport equation is also nonlocal, and that applies to your
coffee cup. YCLIU.
>
> In contrast to Kirchoff's Laws. Those laws assume that all voltages and
> currents are instantaneously connected. They ignore propagation delay
> effects, thus Kirchoff's Laws are non-local. Period.
You're inventing a private language to avoid being wrong in public.
G'wan, Kevin, you're just hitting your stride, man!
>
> Thus... you have the definitions backwards.
>
>>> Spice has to do extra stuff, as in convolution, to handle TLines. It
>>> slows it down a tad...
>
>> As I said, the approximation can often be patched up by hand like that.
>>
>>
>>>> inside the T-line can be modelled with PDEs (Maxwell), but circuits are
>>>> all ODEs. The T-line has invisible internal state, so its circuit
>>>> behaviour is nonlocal.
>>
>>> Not really....
>>
>>> "Non local" pretty much universally means FTL (faster than the speed
>>> of light).
>
>> Nope. It means that the governing equations require information from
>> more than one space-time point. All differential equations are local.
>> Nonlocal systems need integral equations.
>
> We, apparently, have different definitions of locality.
>
> https://en.wikipedia.org/wiki/Principle_of_locality
>
> https://en.wikipedia.org/wiki/Faster-than-light_neutrino_anomaly
>
> Thus, to date the only accepted apparent FTL, i.e. non-local behaviour
> that I am aware of, is the statistical correlations between entangled
> particles, which cannot be used to transfer information at FTL
>
> It is inherent in transmission lines that there is delay for transfer of
> information, which is *the* fundamental property of the definition of
> locality in physics, so it is indeed interesting that there are those
> that claim the opposite.
No, that's a particular definition in relativistic quantum field theory.
We're talking classical E&M here.
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.nethttp://hobbs-eo.com
Reply by Phil Hobbs●August 15, 20192019-08-15
On 8/15/19 2:39 PM, Tim Williams wrote:
> "Phil Hobbs" <pcdhSpamMeSenseless@electrooptical.net> wrote in message
> news:qj3t2i$941$1@dont-email.me...
>>
>> Nope. ODEs don't have memory, T-lines do.� (At least from a circuits
>> POV.)
>>
>
> Great.� Now I have to go buy 20GB of SRAM!
>
>
>> Kirchoff's laws do not apply to transmission lines.� Current
>> disappears into one end and emerges from the other end sometime
>> later.� The currents into the circuit nodes don't sum to zero, and
>> neither do the voltages around loops.
>
> So ports.....don't exist?
>
> Tim
>
A port is not a node. KCL talks about _nodes_.
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.nethttp://hobbs-eo.com