"Veritasium" (YT) - "The Big Misconception About Electricity" ?

[bsfeechannel]

That's an interesting example, it is also an awful example.

Analogies are a bitch. But you get the idea.

Yeah... you may want to update your reading material, maths has changed a fair amount since then.

That's irrelevant. The point is: math is here to help, not to be in the way.

[adx]

first this one...

Would it have been doomed to also replicate "until then engineers could only produce boat anchors" had Bardeen not suggested surface states? Was he a 'proper' physicist, or an electrical engineer who went back to do some physics papers - or someone above classification, and the transistor was waiting for him and his particular set of interests?

John Bardeen had a degree in electrical engineering, but he took all the graduate courses in physics and mathematics that had interested him, and he graduated in five years instead of the usual four.

After that he applied and was accepted to the graduate program in mathematics at Princeton University. Then as a graduate student, Bardeen studied mathematics and physics. Under physicist Eugene Wigner, he ended up writing his thesis on a problem in solid-state physics.

At Harvard University, he worked with to-be Nobel laureates in physics John Hasbrouck van Vleck and Percy Williams Bridgman on problems in cohesion and electrical conduction in metals, and also did some work on level density of nuclei. He received his Ph.D. in mathematical physics.

As you can see, Bardeen was a full fledged physicist and went on to win TWO Nobel Prizes in advanced hacking.

And again, did physicists not have that same four decades to come up with the transistor?

Yes. And when the opportunity presented itself, they were prepared for the challenge. Engineers were not.

That's illogical. If an alien were to read that, they would leave thinking the transistor was invented by a fully qualified electrical engineer, first and foremost. We know it's more complicated than that. I even suggested he was above classification.

When analysing that situation, the effect you want to confirm seems lost in the noise and bias, and only one thing shines through (apart from cleverness persistence and teamwork of course): The almighty dollar.

No surprise, here. Science costs money. That's the whole point of the Nobel Prize.

No surprise here either. My point wasn't that science costs money, it was that the transistor's development was "being funded by an enormous monopoly" and if you have a problem with engineering overtaking the quaint sensibilities of academic physics, then perhaps you should redirect your complaint to some politician. You won't get any complaints from me.

If this thread has shown us anything, it is that most electronics engineering is devoid of any direct use of physics and math,

This thread has shown that electronics engineering devoid of math and physics reduces to a bunch of stupid misconceptions and dogmas bordering pseudo-science.

Touché? It can. But this thread has also also shown us that electronics engineering overloaded with theory of math and physics reduces to a bunch of less stupid misconceptions and dogmas bordering on a religion.

At least pseudo-science has a chance of being falsifiable (and in some places it worked).

And you're arguing with fact: Most electronics engineering is devoid of any direct use of physics and math. I might like that more than you but it doesn't change things.

Mathematics is too abstract for engineering, and its educators should be (and I assume are) more aware of that.

[adx]

My verbal description remains purely verbal and not at all physical, it just describes a physical object.

Your DNA is a description of you. But it is a description that can replicate itself and even build an entire you. We can encode your DNA sequence using the letters ACGT. It'll describe you uniquely. It'll be purely verbal, but once decoded to assemble the actual nucleic acids it represents, it'll be an functional polymer.

It can't replicate itself. It needs the machinery of its own encoding to be present to do so. Chicken / egg oscillator. Arguably it doesn't contain all the information needed to build a (physical) you, because the decoder is encoded by itself. I'm not sure I'm happy with that.

So, is math the encoding of the "DNA" of the universe? That's what David Hilbert and his program aimed to ascertain until Kurt Gödel screwed it all up.

I see what you mean, and don't disagree with the question.

[bsfeechannel]

That's illogical. If an alien were to read that, they would leave thinking the transistor was invented by a fully qualified electrical engineer, first and foremost. We know it's more complicated than that. I even suggested he was above classification.

Bardeen's bio shows clearly that his ability to contribute to the invention of the transistor came from his interest in physics, DESPITE being an engineer. That's the point.

Touché? It can. But this thread has also also shown us that electronics engineering overloaded with theory of math and physics reduces to a bunch of less stupid misconceptions and dogmas bordering on a religion.

If your "alternate view" has been proven to be false over and over again, it is not a dogma, it is a fact.

At least pseudo-science has a chance of being falsifiable (and in some places it worked).

It is science that is falsifiable. Pseudo-science is either false or non-falsifiable, therefore an article of faith.

And you're arguing with fact: Most electronics engineering is devoid of any direct use of physics and math.

Because you make trivial use of them and, therefore, take them for granted, you think they're not used.

When you measure the voltage of a battery with your voltmeter you are repeating what a physicist first did at some point in the past. This is a simple example of a direct use of physics.

When you employ the concepts of quantization and sampling, or calculations, for your wonderful A/D converter, that's a direct use of math.

I might like that more than you but it doesn't change things.

What you don't like is when math and physics really displace you from your comfort zone.

Mathematics is too abstract for engineering, and its educators should be (and I assume are) more aware of that.

Engineering is essentially applied math and physics. Students should be more aware of that.

[SandyCox]

Mathematics is too abstract for engineering, and its educators should be (and I assume are) more aware of that.

"Abstractness" is in they eye of the beholder. My wife is a Mathematician and finds circuit analysis very abstract.

The harder I work at something, the less abstract it becomes. It looks like you missed a lot of the basic electronic engineering principles when you were a student. How did you manage to graduate?

[penfold]

Mathematics is too abstract for engineering, and its educators should be (and I assume are) more aware of that.

"Abstractness" is in they eye of the beholder. My wife is a Mathematician and finds circuit analysis very abstract.

The harder I work at something, the less abstract it becomes. It looks like you missed a lot of the basic electronic engineering principles when you were a student. How did you manage to graduate?

Why do you assume anybody else should be like yourself? The more involved I got with circuit analysis, the more abstract it became. The very concept of a square box on paper representing a resistor that in reality has no end of different physical manifestations is something I never questioned until I began relating circuit descriptions to more genuine mathematical entities. To me now, it seems absurd that I never questioned just how insanely abstract a circuit diagram really is, but I guess we all have different views and backgrounds on it.

[SandyCox]

[
Why do you assume anybody else should be like yourself? The more involved I got with circuit analysis, the more abstract it became. The very concept of a square box on paper representing a resistor that in reality has no end of different physical manifestations is something I never questioned until I began relating circuit descriptions to more genuine mathematical entities. To me now, it seems absurd that I never questioned just how insanely abstract a circuit diagram really is, but I guess we all have different views and backgrounds on it.

I just described my own experience.

Abstraction is a good thing. It removes irrelevant information so that we can focus all our attention on the problem at hand.

[penfold]

[...]
Abstraction is a good thing. It removes irrelevant information so that we can focus all our attention on the problem at hand.

My apologies if I miss-spoke, I might have misinterpreted your intent there. I absolutely agree with the benefit of abstraction and analogies for analysis.

But it is quite a common occurrence on this forum that a (self-teaching) beginner to electronics will pose questions on or seek a purely theoretical route to learning about circuit design and struggling. Similarly amongst early-stage Ph.D. students approaching EEE from mathematics, ACSE, or physics backgrounds, the second it comes to actually build a circuit, develop a test rig, or anything more practical, they struggle. Engineering is fundamentally about actually designing something that'll get built and it does appear that abstraction isn't the main facilitator to that. Being asked "where might I find the non-linear resistors in the Farnell catalogs?", "do you know of a simple circuit that'll convert a current into a voltage?" or "why does this DC amplifier produce a 40MHz sine-wave?" (by embarrassingly intelligent people) is quite telling of the fact that theory and abstraction is not the key, and be quite hampering to beginners. The reverse of that is also true with EEE students struggling so much with ACSE and DSP topics.

[adx]

I was hoping to do all this justice but haven't had time - plus it's tiring!

At first I thought some people had more of less believed what they were taught without really questioning it, but now it is clear to me that they really do believe that they believe it. So I have been trying to see it from those perspectives, because there is some kind of communication difficulty at play (whether or not there is rightness or wrongness).

I don't see why my disbelief that j=sqrt(-1) is such a problem for j. It doesn't change the way reactance works.

I'll need to read Steinmetz better than a glossing over to see if it provides the claimed "proof", and other things about the meaning of i.

[adx]

Actually the best I've got is that the solution to x^2+1=0 gives the property of lateralness that lends itself to phasor analysis, such that it allows the 90 degree phase shift to be represented, and uniquely provides the rotation property when the solution is multiplied by itself.

But I don't know if that is true, or even necessary.

[SiliconWizard]

I don't get what the problem is. Complex numbers are just a useful tool. Like most other tools we use. Their usefulness comes from the fact we get a lot more out of them than what defines them in the first place. If you think even the most mundane tool or model of reality we use is in fact more "real" than this, you're pretty deluded.

If you have a problem with complex numbers, you should have a look at quaternions. You can also look at epsilon numbers.

I find it interesting that some people would have no problem discussing hairy physics and convoluted quantum mechanics, yet find complex numbers "odd".
Seriously, how abstract is math compared to modern theoretical physics? The latter is actually pure maths for the most part.

And as bsfeechannel noted, there is no engineering without math anyway.

[bsfeechannel]

We have two cats, Samson and Monica. Samson is larger and stronger, so anytime I gave them a treat, Samson would overcome Monica and eat all of them. So I started tossing one treat at some 3 or 4 meters away, and while Samson was distracted chasing it, I gave another to Monica.

I did this for quite a while, until one day Samson was a bit sleepy and didn't want to leave his favorite spot on the couch. So I gave one treat to Monica, but I noticed that she didn't eat it. When I gave her a second one, she then ate it. She had learned how to count to 2! She then proceeded to eat the first treat in front of her.

So it was not about Samson anymore. She learned that if she waited for a second treat, she would get it 100%. Of course, from my human brain perspective, her modelling is incomplete, since she could have eaten the first treat right away as Samson wasn't around.

But it is amazing to notice that she replaced the physical object with an abstraction. Forget about disputing with Samson. That's too costly. Wait for the second treat. What is the physical meaning of the number 2 for her? She never told me.

And that's exactly how math works for engineering. Are you going to solve an AC circuit using sines and cosines? Or by trial and error? Knock yourself out. But if you use phasors, you'll get there effortlessly and in the end you get a treat. Any cat knows that.

[SiliconWizard]

That's a fun, but telling parallel.

Yes we use abstractions all the time to get anything done. And even the simplest organisms do that in some way.

Actually, abstractions do not complexify things - they simplify them. If we had to consider every little detail of anything we do when doing it (so, zero abstraction), we would just die before having finished  a single task. For as far as I currently know, the total levels of details of "reality" might be infinite, so anything happening in the universe is actually an abstraction in that sense.

[PlainName]

But it is amazing to notice that she replaced the physical object with an abstraction.

What is the abstraction? I don't think it's really much difference to learning not to grab a bare wire, or that rancid food makes you puke.

[penfold]

[...]
And that's exactly how math works for engineering. Are you going to solve an AC circuit using sines and cosines? Or by trial and error? Knock yourself out. But if you use phasors, you'll get there effortlessly and in the end you get a treat. Any cat knows that.

Has your cat found a suitable method of employing phasors in non-linear circuits yet?

[adx]

I don't get what the problem is. Complex numbers are just a useful tool. Like most other tools we use. Their usefulness comes from the fact we get a lot more out of them than what defines them in the first place. If you think even the most mundane tool or model of reality we use is in fact more "real" than this, you're pretty deluded.

If you have a problem with complex numbers, you should have a look at quaternions. You can also look at epsilon numbers.

I find it interesting that some people would have no problem discussing hairy physics and convoluted quantum mechanics, yet find complex numbers "odd".
Seriously, how abstract is math compared to modern theoretical physics? The latter is actually pure maths for the most part.

And as bsfeechannel noted, there is no engineering without math anyway.

That (and the subsequent stuff about abstraction) is so tangential to what I'm saying (or asking). I know complex numbers are used as a tool. I was (partly) joking when I said "Engineers don't use j (or i)". My question about the "physical relevance" of sqrt(-1) (as a mathematical being) appears to have been too easy to take a different way, but there are only so many ways I can try to explain it without digging an impossibly deep hole (interesting to see how deep it goes!). I thought I was asking about the fundamental mathematical meaning of sqrt(-1)'s physical relevance to phasors or anything. Perhaps that was how it was taken?

My formula x^2+1=0 above has no real solution. It states an impossibility. Imaginary numbers are an algebraic 'what if' to get around that, in the same way a negative number is a what if (what if I remove x units?). Neither imply possibility to a measurable value of x. No problem with either.

Removing x units has clear (but not universal) physical relevance (perhaps I should have said mathematical relevance) to engineering measurements. Yes it's a tool as defined, but easy to explain why.

Why does the algebraic 'what if' solution to x^2+1=0 have direct mathematical relevance to phasors?

[bsfeechannel]

Removing x units has clear (but not universal) physical relevance (perhaps I should have said mathematical relevance) to engineering measurements. Yes it's a tool as defined, but easy to explain why.

Why does the algebraic 'what if' solution to x^2+1=0 have direct mathematical relevance to phasors?

x² + 1 = 0 gives you a hint that what you're looking for is some x that is the side of a negative area. x can be neither a positive nor a negative number, because such numbers give you a positive area. So it is clear that x is in another dimension.

Two dimensions form a plane. If instead of being added or removed from a single dimension, your x units are rotating in a plane--for instance, inside a generator--complex numbers seem adequate to describe your measurement.

[adx]

Ok I'll buy it, despite the hint that the number breaks squaring (the negation operator is functional only once in the square) despite the algebra of the square being the source of the number in the first place.

The question then remains whether this fundamental nature of the number (and complex plane) has direct relevance to phase of sine waves, or whether phasor analysis merely purloins the property of the complex plane as a "handy trick"?

Negation breaks the summing property of addition, but my point is that has real relevance to positive as well as negative numbers. Claiming the same reality and physicality exists for imaginary vs real numbers isn't beyond imagination, but to me, claiming it is no less tenuous than negation in real numbers, seems like it might be false. We are taught (and people believe) it is as fundamental a law to engineering as electrons repelling. That has to be absolutely beyond question to be right.

[penfold]

[...]
Why does the algebraic 'what if' solution to x^2+1=0 have direct mathematical relevance to phasors?

I had half-baked a response to that earlier actually (hopefully that doesn't get taken as evidence of non-causality), I was pondering my own initial reaction to complex numbers from high-school maths. I think that 'what if?' solution is typical of most people's first exposure to complex numbers, demonstrating that there are still "some roots" to an apparently 1d problem. I initially just accepted that it was 'nice' and plodded along.

By about first or second year EEE maths, when functions of a complex variable were introduced formally with power series (of a complex variable), residues, etc, it shed a little more light on things, at least to demonstrate that the function of x, for which we'd only ever assumed to be a function of a real value (and yet had complex roots... go figure) could actually be a function of a complex 'z=x+jy' which more naturally has a complex root, where f(z)=z²+1 is now a surface plot with height defined for values of x and y... only the height is complex but only goes completely to zero at +j and -j (i.e. y=+1,-1). If you were to draw cross-sections of the surface plot (as x²+1 is the cross-section at y=0) and the same function will look slightly different... you can even plot a cross-section at an angle where both x and y are varying... or any arbitrary function that links x and y in response to an arbitrary parameter (I'm too tired to wonder if that was relevant... could be Euler's formula with 'phase' as a parameter... really not sure where I'm heading with that).

Looking at pole-zero responses of linear networks is where it began to make more sense to me. A circuit composed of a combination of real and imaginary impedances, in the Laplace domain will have moments (with respect to varying ω) with a tendency to head towards zero or infinity (as jω in the factors of the numerator or denominator cancels the imaginary part of the root)... except the real component of the root is not 'canceled' by jω and the root doesn't quite go to zero, nor does the transfer function get quite to zero or infinity. The resulting combination of real and imaginary values of the transfer function determines the phase shift of the output with respect to the input.

[adx]

Only time for a partial reply for now:

First, my concern over sqrt(-1) in electrical engineering, penfold has it right: "and the j is an operator rather than a quantity ... it is stretching it a bit far to say that it is a physical quantity".

Did I say it was a physical quantity? Please show me (I've tried to find where I might've implied that but I don't see it). j is not an Ohm. But it is a representation of phase-shift in Ohms and a damn good one. Is that not physically relevant?

Tricky semantics. What I and I assume penfold were referring to was somewhere between a physical unit and representation as a tool. You said sqrt(-1) "has immense physical significance, just as 'zero' and 'negative' have immense physical significance" which I took to be that middle meaning. Saying j is physically relevant is different from saying sqrt(-1) is, to me. The latter being a very abstract mathematical concept, but j being defined as a practical tool by Steinmetz (yes, with overlap). sqrt(-1) is the first whole positive imaginary number (if there is such a thing) hence a quantity (of sorts), j is a rotation operator as defined by SandyCox in (a, b)(c, d)  = (ac-bd, ad+bc) (with j as b or d). They happen to be algebraically identical.

I've explained more since, but I hope that helps explain a bit better where I think I'm coming from.

I don't think it is any sort of tautology to say mathematical concepts are not real, if one then goes on and asserts that some part has physical relevance. Not all engineers are naturals at maths and can easily identify where that link appears (ie goes from nothing to something without explanation). Some people here seem to be struggling with it too - perhaps from over-familiarity.

You might as well be arguing that multiplication has no 'physical relevance' to engineering because you could just add the numbers up... like, yes? What is your point? Should we count on our fingers and toes because applying math makes us feel dumb? 

Yes, if it "adds" nothing practical or needs to be applied abstractly by some engineers who might then not know what they are doing as clearly.

I've said, many times, that engineers can and do get confused by this. And there are some engineers better at it than others. None of that is an excuse. There are way more problems I can solve quickly and efficiently with multiplication than I can with addition - even though multiplication is just an extension of addition.

And that's why. We don't want engineers getting confused on the job. I've 'moved the ruler along' n times to check a calculation, or tipped liquid into a measuring container to work out volume that could have been calculated.

It's not what I meant anyway. My reply was referring to your suggestion that saying all numbers are imaginary (I'm paraphrasing) is a tautology because everyone knows that. For something like sqrt(-1), I don't know where it gets real.

Time for one more before nie nies:

I'm not citing waffle-y texts at you. I'm citing actual engineering practices. You can take them or leave them.
https://www.electronics-tutorials.ws/accircuits/power-triangle.html

Although I've clarified more since, this is exactly what I don't have a problem with. j is defined only in the annotations on the diagrams as a 90 degree shift pictorially and as reactance. j doesn't appear in any of the body text or its formulae. The only hint as to what j might be (as a symbol) is mention of "which is the vector sum of the resistance and reactance".

This is what I mean by things like "to the point they realise sqrt(-1) has no physical relevance, with j being the unit vector that I say it is".

[bsfeechannel]

The question then remains whether this fundamental nature of the number (and complex plane) has direct relevance to phase of sine waves, or whether phasor analysis merely purloins the property of the complex plane as a "handy trick"?

If it is only a "handy trick", it is already useful and worthy of our attention as engineers. We want shortcuts to solutions for our engineering problems.

Yes, if it "adds" nothing practical or needs to be applied abstractly by some engineers who might then not know what they are doing as clearly.

Of course it adds practicality, otherwise it wouldn't be taught. Not only that, it adds insight, which is essential for engineering.

Because you don't have to work with AC circuits, filters, control systems, or RF, and you see no use for it in your daily tasks, it doesn't mean that mathematical concepts like complex numbers should be abolished from engineering.

For working with ADCs, for example, a different set of theorems and math tricks are required.

I could conversely say that the Nyquist theorem is a waste of time, if I my job as an engineer didn't involve sampling analog signals. Or that the Viterbi algorithm, without which CDMA, GSM, WiFi, speech recognition and a whole bunch of other technologies wouldn't be possible, that I had to study while in engineering college, is rubbish if my job as engineer had nothing to do with telecom.

[SiliconWizard]

Any of our views of what reality is is just a "handy trick".

[Alex Eisenhut]

The German mathematician Kronecker famously said "Natural numbers were created by God, everything else is the work of men."
In that context, "everything else" includes zero, negative integers, rational fractions, irrational numbers, etc., since "natural numbers" in mathematics means the set of positive (non-zero) integers.
https://www.cantorsparadise.com/kronecker-god-and-the-integers-28269735a638

Kronecker was a bit of dick and a loon. He made Cantor suffer for nothing...

[TimFox]

The German mathematician Kronecker famously said "Natural numbers were created by God, everything else is the work of men."
In that context, "everything else" includes zero, negative integers, rational fractions, irrational numbers, etc., since "natural numbers" in mathematics means the set of positive (non-zero) integers.
https://www.cantorsparadise.com/kronecker-god-and-the-integers-28269735a638

Kronecker was a bit of dick and a loon. He made Cantor suffer for nothing...

Yes, he had a problem with uncountable infinities.
At university, we joked about attending the "Einstein summation convention" that would be held at the "Kronecker delta".

[bpiphany]

Any of our views of what reality is is just a "handy trick".

This! A vastly under-understood reality-realization.