Why are physicists the electronics experts? - Page 1
Forum section: electronics / general

author: Connecteur
author_rank: Frequent Contributor
timestamp: August 20, 2020, 05:25:36 pm
content: When I look up the answer to an electronics question online, it's often a physicist who is giving the answer. Do they know more about electronics than someone who actually works with electronics?

author: wraper
author_rank: Unknown
timestamp: August 20, 2020, 05:29:58 pm
content: Quote from: Connecteur on August 20, 2020, 05:25:36 pmWhat types of questions in particular? If it's something like Ohms law or other sorts of fundamental stuff, I don't see why they would not.

author: Domagoj T
author_rank: Frequent Contributor
timestamp: August 20, 2020, 06:06:57 pm
content: Electronics is applied physics.

author: Berni
author_rank: Super Contributor
timestamp: August 20, 2020, 06:32:14 pm
content: What question did you ask them?If it is something along the lines of "What kind of circuit should i use to transfer power and bidirectonal communication simultaneously over 2 wires" or "How do i make the switchmode regulator <Insert part no. here> output be digitally adjustable" you are very unlikely to get any sort of even remotely useful answer out of a physicist.If you instead ask something along the lines of "How does a bipolar transistor work?" or "How does an LED work?" or "Why do resistors make thermal noise?" then you are indeed more likely to get a much better answer out of a physicist. The electronics engineers just simply don't care what the electrons are doing inside of that transistor. They can't poke and touch those electrons in there to make them do anything else than what they normally do. They care about the transistors functionality of amplifying current, so they instead know how the transistor behaves and how to use that behavior to do something useful in a circuit. But physicists are way more interested in those electrons whizzing around inside trough those funky energy levels of the junction, while not really caring about what that transistor could do in a useful circuit.This leads to things like the much debated topic around Dr. Lewin and Kirchhoffs circuit rules.

author: TimFox
author_rank: Super Contributor
timestamp: August 20, 2020, 09:27:44 pm
content: Perhaps physicists use electronics more often than electronic engineers use physics?

author: bsfeechannel
author_rank: Super Contributor
timestamp: August 21, 2020, 12:57:06 am
content: The guys who discovered the laws of electromagnetism, quantum mechanics and quantum electrodynamics that govern our trade were all physicists. The guy who discovered the electron was a physicist. Moreover most of the components we use in electronics were invented by physicists or engineers with a deep knowledge of physics. You name it: resistors, capacitors, inductors, transformers, antennas, vacuum tubes, diodes, transistors, ICs, etc.

author: iteratee
author_rank: Contributor
timestamp: August 21, 2020, 01:13:43 am
content: physisist-engineer / engineer-physisists should be out there. Anyone doing cutting-edge R&D on anything in semiconductors would need a few polymaths.

author: coppice
author_rank: Super Contributor
timestamp: August 21, 2020, 01:32:25 am
content: A lot of engineers started out getting a physics degree, and then moved into engineering. I find a lot of microwave people, and people doing deep semiconductor design, have a physics degree.

author: richard.cs
author_rank: Super Contributor
timestamp: August 21, 2020, 09:46:27 am
content: Quote from: coppice on August 21, 2020, 01:32:25 amI did, I find it gives me a different approach to engineering problem solving than people who trained as engineers. More of a "from first principles" kind of thing and it seems to work well in the kind of R&D environment I work in. On the other hand it it has left me lacking knowledge in certain engineering-specific areas, e.g. I have had to work hard to catch up on control theory.

author: capt bullshot
author_rank: Super Contributor
timestamp: August 21, 2020, 09:52:57 am
content: Having understood the underlying physics helps to deal with many real-life electronics problems. Like EMC, noise, interference, efficiency, signal integrity, ...

author: coppice
author_rank: Super Contributor
timestamp: August 21, 2020, 11:38:21 am
content: Quote from: capt bullshot on August 21, 2020, 09:52:57 amYou don't think an engineering degree covers that in great detail?

author: capt bullshot
author_rank: Super Contributor
timestamp: August 21, 2020, 11:50:32 am
content: Quote from: coppice on August 21, 2020, 11:38:21 amMine does. Had a lot of physics stuff to do (wasn't called physics, but rather fundamentals of electrical engineering or whatever the correct translation of "Grundlagen der Elektrotechnik" would be. This did weed out a lot of the people that started their EE studies at the same time I did. Can't speak for the modern BSEE or whatever degrees. To me they look rather small-time in these disciplines.

author: NivagSwerdna
author_rank: Super Contributor
timestamp: August 21, 2020, 11:55:24 am
content: Quote from: Connecteur on August 20, 2020, 05:25:36 pmYes

author: filssavi
author_rank: Frequent Contributor
timestamp: August 21, 2020, 12:08:08 pm
content: Quote from: coppice on August 21, 2020, 11:38:21 amThat is unfortunately not the case.From what I have seen by working with universities around the world that used to be the case (and often still is) is Europe (Italy, Germany, etc.). Here the traditional teaching order is bottom up, starting with lots of math (complex functional analysis, linear algebra etc) physics, electromagnetism in particular, then device physics (pn junctions, BJT’s, MOS) and on from there.This gives you amazing basis for research type work.Unfortunately it’s been some time that we are importing the Top down approach from the US (the UK has been the first, however it is not the only one now). This starts from system level and goes down from there, often times completely neglecting physics, math and even how semiconductor devices work. In a “makery “ type of way.This is obviously fine for 99.9% of the electronics type work (nobody needs to know the width of the space charge region for the mosfet turning on and off the Smart IOT lightbulb) and thus preferred by most companies ( it is faster and cheaper to train engineers that way) however for research (both academic and Company R&D) in Cutting edge fields, this is really sub-optimal (basically it requires the first year of the PhD to be used up in studying the theory that was skipped before.Unfortunately we are now (some countries sooner, some later) importing the Top

author: FransW
author_rank: Frequent Contributor
timestamp: August 21, 2020, 12:17:04 pm
content: I can see the common sense and common denominators in the above discussion.That is why I, after Applied Physics, went for Systems Engineering.A more multi-disciplinary approach.Never regretted this.Frans

author: coppice
author_rank: Super Contributor
timestamp: August 21, 2020, 12:21:44 pm
content: Quote from: filssavi on August 21, 2020, 12:08:08 pmIn the 70s my UK electronics degree went from both directions, and I think that is important. Some of our leaning, like communications, started from a need and worked down to solutions at their lowest level, including the physics. Other leaning, like semiconductor devices, started at the lowest level and worked up to the things you can create from the basic physics.I know in many countries a lot of recent electronics graduates have little idea who to use basic components, like transistors, and can only design from the IC level up. However, not all degrees are created equal. Surely there are still serious degree courses in most places teaching a proper understanding?

author: richard.cs
author_rank: Super Contributor
timestamp: August 21, 2020, 12:35:53 pm
content: Quote from: coppice on August 21, 2020, 12:21:44 pmYes, I have interviewed quite a lot of electronics graduates from a major UK university with a "good" reputation for electroincs, and many of them seem to suffer from this problem, often to a greater amount than you describe. In many cases the lowest-level and most "practical" thing they have done is a matlab simulation of a communications system, diving deep into comms and modulation theory but never having even seen an IC let alone a transistor. In all seriousness we are now tending to recruit electromechanical engineering graduates and other related branches of engineering because so many electronics graduates are lacking in practical electronics skills. That and looking carefully at industry placements and hobbyist experience.Edit:typo

author: Berni
author_rank: Super Contributor
timestamp: August 21, 2020, 12:51:30 pm
content: They do still teach it from the basics upwards here, but it is never called physics. The physics there goes trough the general physics-y stuff like forces, motion, acceleration and going on to waves, light, optics etc.. While its instead called "Basics of electrical engineering" where things go into electric and magnetic fields into how a capacitor or inductor works and onto mesh circuit analysis.Semiconductors take a similar path having a subject dedicated to going from the grounds up in how diodes and transistors work internally up to the more macroscopic model of what a transistor actually does, up to building a single stage amplifier out of a transistor. Ending up doing measurements on transistors in the lab etc..As for building useful circuits out of transistors is just not there. This leaves people stranded with this theoretical knowledge inside of a vacuum. They never get to find a use for it in school so it just gets forgotten that much faster. If any circuits are involved they usually get a schematic handed to them, often also containing higher level building blocks such as opamps. Sure opamps also got explained what they are, how they work and some basic opamp circuits, but i don't think it is explained at any point what transistor magic is inside the opamp in order to make it do what it does, so the continuity from a transistor to an opamp is cut here.So they do teach the underlying physics behind it pretty well but fail to properly connect it all together into a bigger picture.

author: coppice
author_rank: Super Contributor
timestamp: August 21, 2020, 12:59:25 pm
content: Quote from: richard.cs on August 21, 2020, 12:35:53 pmI have heard from some UK academics that health and safety plus cost issues means lab work is mostly matlab work these days.Someone with an electronics degree who has little understanding of basic components is not necessarily a bad thing. Electronics is now a big topic, and every engineer is a specialist of some kind, For example, many careers in electronic engineering can be entirely based on the maths of communications.

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 21, 2020, 01:57:03 pm
content: I suspect that it's either just a random occurrence; or perhaps that among those who work with electronics, physicists are more likely to answer questions online than actual electronics experts.

author: SerieZ
author_rank: Regular Contributor
timestamp: August 21, 2020, 02:55:34 pm
content: My gut tells me that we see Industry experts more doing Webinars, Writing Articles, Books etc. and not really much on stack exchange answering basic (or exceedingly complicated!!) questions.To me the whole Question from OP is way to open and feels like a Bait from a Physics Undergrad to tease his electronics buddy TBQH.I doubt that was the intention tho.

author: dietert1
author_rank: Super Contributor
timestamp: August 21, 2020, 03:20:37 pm
content: Looking at engineering problems in an extended context including physical considerations can sometimes help to find answers. A physicist is privileged in that sense and many physicists like to teach others.Regards, Dieter

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 21, 2020, 04:29:22 pm
content: Quote from: Nominal Animal on August 21, 2020, 01:57:03 pmYeah. I haven't noticed that myself.I suppose that also depends on what you call a "physicist", and what kind of question you ask. If that's something more fundamental about electronics, then that can be true that many engineers may have a problem answering the question properly, whereas a physicist will (but in this case, you may also not really understand the answer.)But if it's a typical "engineering" question, then I would just plain disagree with the above statement in general. People working in fundamental fields are (on average) a lot less able to deal with engineering/practical questions than engineers.Of course, that may entirely depend on what kind of questions you consider and the kind of places you visit. Seriously, if you can't find places online where EEs would usually not be able to answer EE questions, but physicists would, then you're probably looking in the wrong places.This very forum is, IMHO, the very example of the OP's statement being completely wrong in general.

author: Mattjd
author_rank: Regular Contributor
timestamp: August 21, 2020, 05:53:33 pm
content: Quote from: SiliconWizard on August 21, 2020, 04:29:22 pmI think on SO you are more likely to get some very heavy theoretical questions where deep knowledge of the math/physics being applied is required. Whereas on this forum you are more likely to get very general application type questions, or more like realization questions. I've found the members of this forum to be good at the application side of things i.e. general parts knowledge and how/where to use those parts. However the deep theory is lacking. From the deep circuit analysis/signal-processing/E&M questions there seems to be less members that can answer those questions but many people that can answer circuit realization type stuff using lots of personal anecdotes/heuristics.I akin the comparison to say using AoE vs Linear & Nonlinear Circuit (Chua) to learn analog circuit theory. AoE will get you a very hands on experience and teach you real life parts along the way, with lots of heuristics. Chua's book on the other hand will give you deep theory seated in the mathematics and physics of the circuits.

author: Seekonk
author_rank: Super Contributor
timestamp: August 21, 2020, 06:06:06 pm
content: A lot of people in electronics are happy just to let things be as long as they work. If you want to know just how educated a person is in electronics, just ask a question about charging capacitors. At least someone in physics will look it up and give the right answer.

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 21, 2020, 06:56:41 pm
content: Quote from: SiliconWizard on August 21, 2020, 04:29:22 pmI was referring towillingness, definitely notability, though.I don't think that professionals like to volunteer on the net on things they do at their day job. For example, although I was quite active on Stack Exchange for a few years, I never went to the matter modeling (materials.stackexchange.com) site at all. Math, electronics, and POSIX C programming are basically just my hobbies, and I kinda like to help with those.So, if I had to guess, I'd say that the overwhelming majority of people answering questions online do so on topics they have as a hobby, not as a day job. If indeed physicists do answer electronics questions often (which I'm not sure about, it could be just a coincidence in OP's topics), I would guess it is because many physicists like doing electronics as a hobby, and also like to answer questions.Like they say: Those that can, do; those that can't, teach.

author: fourfathom
author_rank: Super Contributor
timestamp: August 21, 2020, 07:27:31 pm
content: Quote from: Nominal Animal on August 21, 2020, 06:56:41 pmI think you're probably wrong about that.I don't think Stack Exchange even existed when I retired from my engineering career (almost 20 years ago), but I was trying to help out on-line in my areas of expertise as far back as the USENET days. I'm definitely a practical hands-on engineer, not a deep theory guy, so I'm happy that the physicists and physicist-engineers are here to answer those deeper questions. I do try to help when I think I know what I'm talking about, and would certainly have done so when I was working full-time (assuming I could have found the free time).

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 21, 2020, 09:13:54 pm
content: Quote from: Nominal Animal on August 21, 2020, 06:56:41 pmWhereas there may be some truth to that, you can't generalize. Again, this forum is a counter-example. Sure there are some retired people and hobbyists on here, but there also are MANY active professionals that do help on a regular basis.To elaborate a bit, I think professionals actually attract professionals. The fact Dave (Jones) was an active professional for many years before starting EEVBlog was a big part of it. That did attract a lot of other professionals, and not just hobbyists. OTOH, there are many other forums out there that are not created/run by professionals and will mainly attract hobbyists.Quote from: Nominal Animal on August 21, 2020, 06:56:41 pmWhereas that's kind of true when people choose a career path, that's not an absolute truth in general. Many professionals will teach/share their knowledge and experience, especially as they get more advanced in their career. So getting back to EEVBlog's forum, your statement is even kind of insulting. There are again a lot of people on here that have done a lot (and many that still do) and help or teach when they get a chance.As to what motivates professionals: yes many experienced engineers actually like to help/share (as fourfathom said.) But many also do this for expanding their network/get some exposure, and that's fine too.

author: TimFox
author_rank: Super Contributor
timestamp: August 21, 2020, 09:22:59 pm
content: My examplar is the Clerk from Chaucer's Canterbury Tales:"Sownynge in moral vertu was his speche,And gladly wolde he lerne, and gladly teche."

author: tszaboo
author_rank: Super Contributor
timestamp: August 21, 2020, 09:33:27 pm
content: Well, thats normal. If you ask an " I=U/R" question, you are not going to get an answer online from an engineer, because he will be busy navigating to a different webpage that is actually interesting. Its not that we dont know the answer, but it is probably just to elementary.Now, ask the physicist, to recommend an opamp with low offset voltage for battery powered electronics. Or with the previous example, I=U/R is interesting, if you need to do Monte Carlo on the resistor values, the U changes based on the battery voltage, the resistance has to be from the E24 table, cheaper than cent, and the current has to be kept below the safety limits of a harmonized standard.Besides, engineering is all about problem solving. If you can google your question, and solve the problem that way, do that.

author: Sal Ammoniac
author_rank: Super Contributor
timestamp: August 21, 2020, 09:46:48 pm
content: Quote from: filssavi on August 21, 2020, 12:08:08 pmI went to university in the US and it was definitely what you describe as "bottom up".

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 21, 2020, 11:25:17 pm
content: Quote from: SiliconWizard on August 21, 2020, 09:13:54 pmNo facts in my post, just vague guesses as to why one might make the statement OP did in the initial post.Quote from: SiliconWizard on August 21, 2020, 09:13:54 pmSure, I agree; but I think you're reading something in/from my post that wasn't there (or if it is, it is in error).I was not talking about hard rules that apply to all sites, as in defining characteristics that are common to all discussion sites. I was thinking about all the Q&A sites out there, and how the discussions and questions I most commonly see are hobbyist-level and not professional-level stuff. Because there are lots more hobbyists than professionals out there babbling on the intertubes – and I'm not talking about EEVBlog here, or any specific site, but rather in statistical terms – on a random site, you're much more likely to engage with a hobbyist than a professional.(So, to repeat, if one asks an electronics related question on some random Q&A site, and if it turns out you are more likely to get a response from a physicist than an EE professional, I think it could be because there are more talkative physicists who do electronics as a hobby than EE professionals on typical sites. I am not even sure if that actually happens. On EEVBlog, the situation is completely different.)If we switch to discussing EEVBlog, then I absolutely love to read about real world experiences and advice. That level of information and experience is not easy to get access to in general on the intertubes; EEVBlog is definitely unique in that sense. (And I wouldn't want anyone to think that the net is full of sites like EEVBlog, because it isn't; there are not that many sites where professionals engage so much with hobbyists.)Quote from: SiliconWizard on August 21, 2020, 09:13:54 pmNo! That was a self-referential joke. As in, I try to teach, even though I'm just an uncle bumblespork. I've been told it is in my blood.Quote from: SiliconWizard on August 21, 2020, 09:13:54 pmWhy would you consider it that way?I've reread my posts in this thread, and can't see a reason why one would think that. It certainly wasn't my intention.

author: eti
author_rank: Super Contributor
timestamp: August 21, 2020, 11:31:52 pm
content: Here's my very simplified understanding of this:All physicists will generally (I should HOPE so, anyway) know electrons, protons, neutrons etc and how they behave, so electronics is just a practical manipulation/physical realm engineering of solutions based around those behaviours.Not all electronics engineers will, or will need to know the above, depending on their area of focus. They know that electrons flow, in current, and they know that for X potential across Y resistance, Z current will flow, and all the variations of that. If you can solder, measure, test and diagnose, one isn't required to know all the aspects of the molecular realm that a physicist would generally know (at a bare minimum level, I'd think).What I am trying to say is that, if I seek an expert on soldering, faultfinding, circuit repair and measurement of signals, I'd ask an electronics engineer. However, if I wanted a fine grained explanation of electrons and the molecular level behaviour of that kinda thing, I'd seek a physicist.You get my drift?

author: Rick Law
author_rank: Super Contributor
timestamp: August 22, 2020, 05:01:03 am
content: There are so many branches in Physics and many of them use electronics. Electronics is a "must learn" if you are a Physics major.Before I get into it, first some background. There is Experimental Physics and Theoretical Physics, this is a function focused description. Then there is the subject field focused description such as Particle Physics, Plasma Physics, Astrophysics, etc., etc.A. Why Physicist learns lot of electronicsExperimental Physicist uses a lot electronics and much of it custom designed by the Experimental Physicist themselves. The equipment's function and manner of operations are designed by Physicist. The electronics may be designed in collaboration with Electronic Engineers as needed. As Physicist participate in such activities, they learn more EE stuff because whatever experiment they designed, EEmay bethe "what" that makes it happens. After it happens, EE islikelythe "what" that takes the measurement. So they must understand EE to know how far they can push -- you don't want to design an experiment that cannot possibly be done. Budgetary constrains also pushes more work to be done "in-house." That is, have a Physics graduate assistant do the work and have him/her get advice from an EE guy.A good example may be CERN/LHC (Large Hadron Collider). There you have some of the most advanced electronics used by Physicist - In this case, Experimental Particle Physicist mostly but not all. All custom designed by Physicist, again, in collaboration with Electronic Engineers as needed.Another example is Carbon Dioxide, used in lasers. Experiment Physicist working in that field (and other Physicist using lasers heavily) would know as much about Carbon Dioxide as most Climatologist. They are the ones who like to argue with Climatologist about Carbon Dioxide's role in warming of the globe. One more example is Computer Science, every Physicist has to use computer in one way or another. So some Physicist became good computer programmers as the need arises.B. Why Physicist is more likely to answer questionsNow above perhaps explained why Physicist typically understand some electronics, but that doesn't explain why Physicist tend to answer questions. Myopinionis: May be that is just a (self) selection bias. Those going into Physics like to understand things instead of just applying things. And liking to understandwould likely lead toliking others to understand it too. Hence, they are likely to take time to answer questions. May be... What is a physicistAs to the question "What is a Physicist?" From the perspective of someone with a mere master degree in Physics and having done some research as a graduate assistant... I would say a Physicist is one who works in the field of Physicist.Many would say a PhD in Physics is necessary to be called a Physicist. But I think that would be unfair to those who is working in the field doing active research but without a PhD. It would be rather hard to find work as a Physicist without a PhD, but if that person is good enough for others to pay him/her to do Physics, that person is good enough to be called a Physicist.Footnote: Princeton University Professor of Physics William HapperAt time mark 5:11 is the question posted by the interviewer "...What do you mean CO2doesn't make much difference [with climate]...".At time mark 5:20, he answered "...I know a lot about CO2compare to most Climate Scientist because we make CO2lasers. CO2is a very interesting molecule..."

author: FransW
author_rank: Frequent Contributor
timestamp: August 22, 2020, 09:39:04 am
content: I would say that there exists a lot of self-induced occupational myopia.One sees what one wants to see. It often can be compared with thedifference between a pigeons intuition and occupational intuition, basedon knowledge and experience.Knowledge and/or intuition often is present in a compiled version.Reconstruction into parts can be quite a task.I did like the contribution of "Rick Law".He describes the fields in question in a broader context, without too muchlimitations and an open view to whatever can influence any observations and/ormeasurements.Being aware of one's own limitations the question: "what do you not know"(a silly question if put in this way) can be answered by oneself.Curiosity is a gift, the brains to use it as well.The solution for many questions is to reduce complexity.When someone describes a problem as complex, chances are that the understandingis still far away. The question that remains is: did you really understand the subject.Calling it complex is not contributing to a solution.Frans

author: EEVblog
author_rank: Unknown
timestamp: August 22, 2020, 09:52:30 am
content: Quote from: Berni on August 20, 2020, 06:32:14 pmYes, that was a absolutely classic case of the way an electronics engineer sees things, and how a physicist sees things. In essence both of them were "right".

author: coppice
author_rank: Super Contributor
timestamp: August 22, 2020, 10:21:24 am
content: Quote from: Rick Law on August 22, 2020, 05:01:03 amWhen I was at college doing my electronics degree the material used for the physics people's circuit design course was basically the same as ours. Their course was presented with a more instrumentation focus, but it covered roughly the same ground.

author: iteratee
author_rank: Contributor
timestamp: August 22, 2020, 12:38:37 pm
content: Quote from: coppice on August 21, 2020, 11:38:21 amIn 4 years? With half of courses being irrelivent bullshit and the rest being tought via a process that could only be conceived by an alien that doesn't understand human learning?Nope. No chance.*disclaimer: I'm part-alien and don't understand normal human learning either. As evidenced by the fact that normal people claim education works for them, for incomprehensible reasons.

author: pidcon
author_rank: Contributor
timestamp: August 22, 2020, 03:11:58 pm
content: I would imagine that physicists work in an academia-like environment and would be more open to communicating their ideas and definitely will take the time to explain how things work from their perspective. Maybe the engineer was too busy to write out a long explanation.

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 22, 2020, 05:56:24 pm
content: Quote from: Nominal Animal on August 21, 2020, 11:25:17 pmOh nevermind, I likely overinterpreted what you wrote. But in the context of the thread and of what you said above, it was kind of conveying the idea that most people helping others out on tech forums must just be hobbyists or people who haven't achieved anything much, which was backed by your "I'd say that the overwhelming majority of people answering questions online do so on topics they have as a hobby, not as a day job." sentence. So the "teachers are not doers" part that followed just looked like a nail in the coffin. Re-read better, I guess you'll have to admit it was a gross generalization and could be misinterpreted.Of course generalizations are just that. "Online" is a pretty big place with a lot of different things happening. I'd personally be hard-pressed to say what a "majority" of people do "online" and why.But back to the topic, the OP's statement IME is certainly NOT true.

author: SiliconWizard
author_rank: Super Contributor
timestamp: August 22, 2020, 06:20:49 pm
content: Quote from: NANDBlog on August 21, 2020, 09:33:27 pmI second this.Several of us asked what kind of questions the OP was referring to. And apart from the kind of forums they visit, I think this is the key point here.If you ask a fundamental question about electronics - it could be either pretty advanced, in which case a typical engineer may not be comfortable answering, and a physicist will be better at that - but as I said earlier, you may not understand your own question after they have fully answered. As Dave just mentioned, the whole thread about Kirchhoff's laws was a good example. Is that kind of questions what the OP had in mind (and calls people able to answer them properly "electronics experts")? Frankly as several of us already said, you'd need to ponder what engineering is all about.Or, it could be a very basic question, as NANDBlog just said, in which case many professional engineers will just pass - they usually have better things to do than teach elementary things to typical students (or hobbyists). So obviously it's not because they are not expert enough in that case, just that they have better things to do. The value of an experienced engineer on an online forum is their experience and practical knowledge, it's not teaching random people very basic things that anyone can find in a textbook.

author: richard.cs
author_rank: Super Contributor
timestamp: August 22, 2020, 06:37:14 pm
content: Quote from: coppice on August 21, 2020, 12:59:25 pmFor this particular university the cause seems to be more related to internal politics.And yes of coursesomeengineers specialising in comms theory is good and necessary. I am not sure however that a masters in electronics should focus so heavily on it to the detriment of everything else. Or to put it another way, the kind of engineer that my employer requires aligns poorly with many UK university electronics courses, to the extent that when they apply for an electronics engineering position we are starting to count an electronics degree as a possiblenegative. I don't think our needs are that weird and oddball that this should be the case.We've also become a bit suspicious of top grades - it seems to correlate heavily with the kind of student who is very good at exam technique and studies very narrowly to optimise academic results at the expense of subject understanding.

author: Rick Law
author_rank: Super Contributor
timestamp: August 22, 2020, 06:41:18 pm
content: Quote from: pidcon on August 22, 2020, 03:11:58 pmRE:"...physicists work in an academia-like environment and would be more open to communicating their ideas..."That would be the ideal, but that is not the real world. A lot of careers and money are on the line.Say for example, Dark Energy. It is the current accepted "standard model". A lot of money is on the line. You have to search really hard to find Astrophysicists who openly voice their doubt. Doing so will pretty much limit your grants and career rather quickly. You have some "voices in the wilderness" and that is about it. If your publication submission doesn't agree with the "standard model", good luck getting it published. It can be done, but certainly not easily. Should their objection of Dark Energy be proven truth, a lot of "heavy weights" (establishment, including Nobel Laureates) will be handed a good size serving of humble-pies.But, the world of Physics is changing...First a quick fact: LHC found the Higgs particle, but absolutely nothing else! Super Symmetry is now in doubt -- All the SUSY particles we hoped for, no SUSY particles found at all! Not a one. Proposals exist to upgrade LHC (14TeV, about 27km ring) to about 8x (110TeV) by adding another ring at about 100km radius - hoping may be we will find some (SUSY and the likes). Tons on money there for everyone to get a piece of that pie.The fallout of no SUSY: Physics today is in crisis or in an era of great opportunities. String Theory have been sucking all the top brains of Theoretical Physics for the last few decades, but it is now in great doubt. The Standard Model for Particle Physics while works but too much seem like patch-work, is therefore lacking a way to get out of that patch-work construct.It is now finally the time to call some "standard models" into question. You can still have a career if you openly question "Standard Model for Particle Physics" or the validity of String Theory today.EDIT - missed the re:"... ..." in the first line. Corrected a "could" to a "can" in the last line.

author: Nominal Animal
author_rank: Super Contributor
timestamp: August 22, 2020, 07:58:55 pm
content: Quote from: SiliconWizard on August 22, 2020, 05:56:24 pmI see. I definitely didn't intend it that way. Again, I am horribly bad at expressing non-technical things in English; the non-technical undercurrents escape me, and in my own written output tend to be just noise.Therearea lot of professionals on the net. I tried to convey aguessthat perhaps hobbyists find it difficult to express their questions and problems in a way that attracts the interest of a professional to answer; that many questions instead get answered by other hobbyists.I am not claiming that those who answer are hobbyists, just wondering aloud that it could be possible that when asking vague, not-very-well formed questions, to get answers from other hobbyists, because professionals find the hardest part is to understand what is the actual problem the asker is trying to solve, or something along such lines. So, when asking questions about electronics, it perhaps could be that some questions attract answers from hobbyists that happen to be physicists, because a lot of physicists with electronics as hobbies (I know about half a dozen or so) also like to ask and answer questions (the ones I know that have electronics as a hobby happen to also be that way, myself included – and I am aware that I oftentimes seem to have a "teacherly tone" and seem like I know more than I do, as just a hobbyist in electronics, which lead to the attempt at a self-deprecating joke). And all this assumes that OP's observation is correct, which I am not at all sure about; I think it more likely that it is just confirmation bias, or a complete coincidence.On a completely different track, human minds are not at all good at discerning if something happens often or not. We have exceptionally strong perception "filters" or "lenses". Consider the following attention test:and you'll understand what I mean: our conscious perception is highly selective.The scientific principle about repeatable experiments is the best tool I know of of overcoming those. Practical experience, in the best case, falls into the same category, unless done by rote. People who have acquired experience on how to keep things working in a dynamic experience have a lot to teach; and electronics, especially electronic design, is a complex subject where nothing is "perfect", and that makes EE experience such valuable to me personally. So, if you read anything written by me that seems disparaging of EE or practical engineering, let me know so I can fix, because that is an error, categorically. (I do often wail against people who do not do the work, and produce shoddy work, but even that's not about ability, that's about effort or exploitation.)I personally like to answer very specific types of questions that also interest me, and in those cases can get quite in-depth even if I have no idea of the actual answer myself beforehand. Among those questions, and other answers to the ones I've tried to answer, there are roughly three categories: drive-by-statements (that either give a formula, link, or statement) without any reasoning, often basing the answer on authority; other hobbyists (either having solved the same beforehand, found an answer elsewhere, or happen to know the answer, or how to find the answer); and professionals. It is my feeling, without any actual statistics, only based on my "gut feeling" related to the thousand or two questions I've (tried to) answer on the net, that the middle category, hobbyists, is in the majority.I do not place much value on that feeling at all, because the questions were on very specific topics. To me, it is barely enough to speculate on.So, if anybody felt slighted about any of my statements in this thread, I do apologise: no slight was intended. I don't see any real way to find out if OP is right or wrong, and it does not really matter enough to more than idly speculate on.

author: bsfeechannel
author_rank: Super Contributor
timestamp: August 23, 2020, 12:34:54 am
content: Quote from: EEVblog on August 22, 2020, 09:52:30 amUnfortunately, that's not true.Tom Lee, that you interviewed onThe Amp Hour Electronics Podcast, says the following in his book,Planar Microwave Engineering: APracticalGuide to Theory, Measurement, and Circuits, a book that every wannabe microwave engineer should read:As we noted early in this book, it is important to remember that conventional lumped circuit theory results fromappproximatingthe way the universe behaves (in particular, fromsetting to zero some terms in Maxwell's equations[i.e. using special cases of those equations], effectively treating the speed of light as infinite). The much vaunted"laws" of Kirchhoff are not really laws at all; they are consequences of making simplifying approximations, and sothey ultimately break down.²² Failure to acknowledge this fact is the source of an infinite variety offalse conundrums, many of which are debatedad nauseamon various internet chat sites ("proof that physics is broken"[or that engineers see things different than physicists]and that sort of thing, written by folks who are often wrong but never in doubt).Chapter 21 "Antennas", p. 688.The bold letters and quotes between brackets [] are mine.Tom Lee is an engineer..He published this in 2004.And that's the whole point of the engineering degree: make you see things the way a physicist sees so that you know exactly what the consequences of your simplifications are. Engineers need to simplify things for practical reasons, but they can't afford to see things in a different way. Engineering is not an amusement park. It is serious business.So the truth is that some engineers insist that the simplified way the see the world are the fundamentals, get puzzled when it fails and are proud of their ignorance, while a lot of other engineers endeavor to see the world exactly as physicists do, know that their simplifications are prone to break down, and thank the physicists who point that out to them.

author: EEVblog
author_rank: Unknown
timestamp: August 23, 2020, 12:49:25 am
content: Quote from: bsfeechannel on August 23, 2020, 12:34:54 amI used quote marks around the word "right" for a reason.

author: iteratee
author_rank: Contributor
timestamp: August 23, 2020, 05:36:55 am
content: Quote from: bsfeechannel on August 23, 2020, 12:34:54 amErm is this not sort of obvious common-sense? I knew this prior to any study of electronics and zero physics education. I'd suspect anyone that's pondered this will have noted the issue.The manual distributed by S.I. IIRC explicitly disclaims that relativity is essentially ignored throughout. Meaning the basic definition of voltage as an instantanious measurement across space necessarily violates your light cone (duh). I recall this being explained rather dismissively as a niche detail applicible only to "specialized fields". Well it's pretty damn fundamental to everyday electronics.Any geek kid with hilarious gamer P.C. laced with fruit loopy LEDs has tweaked their memory timings, has intuition of phase velocity, and can tell you how many picoseconds apart their DRAM slots lie from CPU.

author: Rick Law
author_rank: Super Contributor
timestamp: August 23, 2020, 06:43:59 pm
content: Standard theory today is: if you are traveling with an electrical system (say, a PC on a space craft) at relativistic speed, everything should work just fine. If you are using wireless to send signal from your space craft off to somethingnot traveling with you, that is where you will run into trouble -- apart from your getting out of range within milliseconds, the signal will be frequency-shifted. Another space craft traveling along side at similar speed should however receive the signals just fine.But, I can't think of anything we are doing where relativistic effect becomes significant... The fastest thing we ever made was the Juno probe. Back in 2016 when it was about to go into Jupiter orbit, with Jupiter's gravity helping, it was traveling at about 266,000 km/h (0.00025c). That was about 2.5x the speed we are orbiting the sun. At 0.00025c, relativistic effect is tiny rounding error.As to Kirchhoff's Law or issues regarding the simplification... Let me put it this way:What is the conductivity of an electron?That question doesn't even make sense. But it is a reminder of something we often forget: electricity (voltage/current) is a statistical emergent phenomenon - emerged from a flow of a large number of charged particles. Rather like heat/temperature emerging from random vibrations of molecules.As such, electronics and electrical rules applies only in the "normal world" where the statistical models were compiled and thus can apply.When you deal with statistics, there is no meaningful exact solutions. You only get probabilities.EDIT:The initial writing (above), I was trying not to be too direct. That risk offending people. But re-reading the post, I think I did not get the point across. So I am adding this few more direct statement. Hope I am not offending anyone.Don't fool yourself into thinking we can solve those problem analytically with exactness. Even today, we cannot solve Three-Body gravitational problems exactly. We do that with approximations. We cannot solve relativistic equations analytically with two black holes orbiting each other (when they get very close, there is where it counts), we have to solve it numerically.That didn't stop us from going to moon (moon + spacecraft + earth = 3 bodies), that we can't deal with orbiting black holes didn't stop us (LIGO) from detecting a black hole merger with gravitational waves.So there is nothing wrong with approximations. They are just fine. And as always, we need to apply solutions knowing the limitation, and all solutions are limited in domain(s).

author: TimFox
author_rank: Super Contributor
timestamp: August 23, 2020, 07:11:33 pm
content: A simple example of everyday things with relativistic features.Linear-accelerator x-ray sources (used for radiography and radiotherapy) achieve electron kinetic energies from 2 MeV up to over 20 MeV. The rest mass is 0.511 MeV.

author: Rick Law
author_rank: Super Contributor
timestamp: August 23, 2020, 07:35:02 pm
content: Quote from: TimFox on August 23, 2020, 07:11:33 pmBut the electronic equipment themselves are not traveling. So we need not deal with the relativistic effects of electronic. The radiography detecting/capturing part of it will need to think about the relativistic effects to the extend necessary.Is it presence/absence or does the gradation of energy level matters?

author: TimFox
author_rank: Super Contributor
timestamp: August 23, 2020, 07:37:44 pm
content: The relativistic velocity of the electrons is important to the design of the accelerator.

author: Berni
author_rank: Super Contributor
timestamp: August 23, 2020, 07:45:19 pm
content: GPS Satelites have to deal with the relativistic effects.Firstly the atomic clocks up on the satellites run slightly fast due to being slightly out of earths gravity (also slightly slowed down due to going so fast, tho the effect is weaker so it looses out). But that is fixed by adjusting the trim on those clocks to match the ground clocks, not that it would matter since GPS would still work fine as long as all the clocks run slightly fast by the same amount.The more observable effect of relativity is the fact that the GPS carrier signal varies by up to a few KHz due to the Doppler shift of the satellite moving towards or away. This relative frequency shift is measured by GPS receivers to get some extra information out of the signal on top of the usual CA code pseudorange measurement.

author: Rick Law
author_rank: Super Contributor
timestamp: August 23, 2020, 08:35:27 pm
content: Quote from: TimFox on August 23, 2020, 07:37:44 pmQuote from: Berni on August 23, 2020, 07:45:19 pmYeah, my initial reply there was poorly worded. My point was, the electronics are not at relativistic speed, so the electronics themselves don't have to deal with the effect of traveling at that speed.Neither the linear accelerator itself nor the detection system itself is traveling. The xray (particle) is. The accelerator of course is designed with that in mind so it knows where the particle is as it accelerates the particle. But neither the accelerator nor detector themselves is traveling, the electronic components are stationary so they don't have to deal with relativistic effects on how the components work.If the particle's energy level matters, then the particle's speed has to be factored in with energy calculation. Other than that, the application is rather like a lux-meter, absorb photon which is actually traveling at light speed and tell you how bright it is at the point, but the electronics themselves doesn't need to deal with any relativistic effect regarding itself traveling at relativistic speed because it isn't.GPS: The electronics in the satellite are not traveling at relativistic speed, therefore the electronics doesn't have to deal with relativistic effect on its electronics due to traveling. The electronics themselves will work as well stationary or moving. However, the GPS application is one in timing, the timing calculation has to to deal with the time dilation.

author: Buriedcode
author_rank: Super Contributor
timestamp: August 23, 2020, 08:39:05 pm
content: Quote from: Connecteur on August 20, 2020, 05:25:36 pmWhere exactly are you getting your "answer" from? Online is a big place - with thousands willing to answer questions regardless of any experience or qualifications, so ultimately you have no real confidence in the accuracy of their answer. Places like stackexchange and Quora are full of self-professed experts who can give wildly inaccurate answers with an air of arrogance - which really means nothing, they could be anyone.It could be that the people who answer the most questions on the forums you ask, just so happen to be physicists who have retired, or you're asking the question on a forum/website that is frequented by physicists. Also, the title of the thread implies that the answers you got are from physicists who call themselves experts in electronics. Or did you just assume they were expects because they answered? It's another "lets post something controversial and see who bites" thread.We've got three pages of replies, without a post from the OP.

author: TimFox
author_rank: Super Contributor
timestamp: August 23, 2020, 08:51:28 pm
content: The electron velocity is relativistic; x-ray photons, being massless, must travel at the speed of light. When setting up the accelerating cavities and excitations, one uses the relativistic velocity of the electrons as they gain energy.When I took freshman Electricity and Magnetism, we used a wonderful textbook by Purcell. He introduced magnetic forces by showing that they resulted from relativistic effects on the motion of charged particles, even at the very low drift velocity of electrons in a conductor. That textbook (which cost less than $10 back in the '60s) is stored now, but I found this (curmudgeonly) discussion of Purcell's demonstration online:http://physics.weber.edu/schroeder/mrr/MRRtalk.htmlOne of his complaints is how much that book costs now.There is Special Relativity in the real world; General Relativity is less important to your day-to-day life.

author: Rick Law
author_rank: Super Contributor
timestamp: August 24, 2020, 03:53:37 am
content: Quote from: TimFox on August 23, 2020, 08:51:28 pmWe are on the same page.Special relativity has not been the discussion here anyway. Fast but sub-light speed is what we have been talking about, so only general relativity is applicable here.I called it "a rounding error" in my original reply under discussion here, you call it "less important to your day-to-day life." Not exact same wording, but in general agreement I would say.I should however consider GPS further, but I wont. That one really straddle the fence, but I gotta eat so I wont worry about GPS for the time being.

author: Berni
author_rank: Super Contributor
timestamp: August 24, 2020, 05:33:10 am
content: You are not going to see relativistic effects within the same blob of circuitry, no matter how fast it goes, that's sort of the point behind it that you can't detect your own absolute speed, only relative speed to something else.GPS is one of the rare cases where you can see it happen because the fast moving satellite and slow moving receiver are communicating over a radio link. So even if they are not one physically connected circuit they are exchanging information. But even then all of this is only easily noticeable because the satellites have incredibly precise clocks in order to make such tiny timing differences show up (rather than getting lost under the clocks own natural drift)If you wanted to see relativity within the same circuit then i suppose the best bet is to build a ring laser gyroscope using coax cable instead of fiber optics. Send a high frequency sine wave in a clockwise and a counterclockwise spool of coax and compare the timing while rotating the whole thing. Since its going along with the rotation and counter to the rotation you get a phase shift as if one of the cables got longer during rotation. Tho the effect is again really really tiny so they prefer using fiberoptics for actual gyros (fiber is tiny and light has a short wavelength).

author: paulca
author_rank: Super Contributor
timestamp: August 24, 2020, 11:11:21 am
content: Electronic Engineering.Engineering = application of science to solve problems.The physicists work out how things work, present that research to engineering who work out how to solve problems with it.

author: FransW
author_rank: Frequent Contributor
timestamp: August 24, 2020, 01:06:19 pm
content: Quote from: Rick Law on August 22, 2020, 06:41:18 pmThere is a vast territory for a talented physicist to use his/hers abilities.Not the physicists that copy, publish and summarise other physicists work.The simplicity of the "Standard Model", "Big Bang" and "Dark Matter/Energy' always makeme feel uncomfortable.The lack of abstraction is too strong. There is so much absent.It is like the "-2x𝞼" from the median of the IQ-Gauss curve applied to the "highly gifted".

author: TimFox
author_rank: Super Contributor
timestamp: August 24, 2020, 01:26:49 pm
content: Quote from: Rick Law on August 24, 2020, 03:53:37 amTo clarify the discussion: Special Relativity (the first of Einstein's theories) deals with "inertial" reference frames in uniform motion (constant velocity), and includes the dilation of time with velocity and the speed of light as a maximum. Here, he introduced the Lorentz factor(1 - v2/c2)-1/2.General Relativity (the later theory) deals with reference frames in non-uniform motion, including acceleration and gravitation. Motion around a circular orbit, for example, involves acceleration. As an undergraduate, one exam question involved a sealed boxcar with a helium balloon tethered to the floor. When the train accelerates to the east, what direction does the balloon move (with no drafts from the outside air)? The simplest answer is to invoke General Relativity. (A gravitational field is equivalent to an accelerated reference frame.)

author: Rick Law
author_rank: Super Contributor
timestamp: August 24, 2020, 08:08:37 pm
content: Quote from: Berni on August 24, 2020, 05:33:10 amThank you!That was the whole point I was making... You wont see it within the same circuit. Anything/anyone traveling with the circuit wont see it. And I pointed out the issues when sending signals off to someone not moving with the circuit.That whole paragraph beginning with "Standard theory today is: if you are traveling with an electrical system..." seem to have been ignored. Instead, the focus of the discussion was on the side comment paragraph that we really hasn't made things that go that fast.I knew I could have worded it better in that initial reply, but at least you got what I was saying. I'm pleased with that.

author: TimFox
author_rank: Super Contributor
timestamp: August 24, 2020, 08:41:49 pm
content: A reasonable description of the (relativistic) Sagnac effect in the fiber-optic gyroscope:https://link.springer.com/chapter/10.1007/978-3-540-39490-7_3