I'm an accountant. I feel like I walked into the wrong classroom but stuck around because the teacher was so good. I actually understood this very well; thank you.
Lol. Don't hype yourself up. Watching a video without jargon words and writing a comment that you understand doesn't mean you are smart. Try doing application and you'll never want to pick up an oscilloscope again.
I am an electronic engineer who studied in the best engineering school in my country. I've never had an explanation so good in my transmissions line course while in college. Simply amazing!
Not gonna lie, im an electrical engineer (power systems) and never encountered smith chart except through the internet.. we just did the transmission line theory and calculations by hand. i feel like branching transmission line grids and stuff like bewley diagrams become hectic and complex very easily, so it might lose utility
@matteod2567 im still in college and our teacher made us use them in class, he did say we'd probably never see them again though. the chart is pretty slick when it works!
If you're going to do RF work, you need to make the Smith Chart you're friend. Even circuit simulators like TopSpice can show you results on a Smith Chart. Getting RF signals around anywhere on a board, or to an antenna or load REQUIRES a good matching impedance. Being able to navigate around one helps you understand what parts you need and where to put them when you're designing your circuit, and can even help you debug your circuit and find problems when your prototype doesn't work. I don't use it for my current job, but I did for my last one, in the design of a 2GHz satellite receiver, and for matching a 600MHz transmitter to a carefully constructed matching circuit that powered a small quartz tube to generate LOTS of UV light. Good luck with your studies!
@Cynthia_Cantrell yeah even the network analyzers we used in class show their results on a smith chart, and by seeing how the curve moves around you can get a lot of info out of it really quickly. it's what I love about EE, yeah there's complicated math but you can see that math working in the real world
@@XDbored1WHAT IS E=MC2 is taken directly from F=ma, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS the rotation of WHAT IS THE MOON matches the revolution. GREAT. Gravity is an INTERACTION that cannot be shielded (or blocked) ON BALANCE. It ALL CLEARLY makes perfect sense ON BALANCE. Consider WHAT IS THE EYE ON BALANCE. GREAT !!! By Frank Martin DiMeglio
@@jrfcss its used to calculate losses to reflection so you would want to use it for anything that is either high frequency signalling or high power transmission, most DIY stuff probably doesn't need it but people still do impedance matching for like custom modded speakers with HIFI audio.
Educating is like comedy. It is all in the preparation and delivery that provides for the audience either “getting it” or not and this was exceptionally presented in an all relatable fashion that did not require people knowing “inside information”. Nice work.
@mkehammond7277 I'm an electrical engineer and use this almost every day and while I "get it" it took me months to grasp it. Don't beat yourself up this is EXTREMELY difficult to understand
@@skyking6989 If you understand the basic effects of R, Lx and Cx and the effects of object form on the same then you get it, minus the formulas. The formulas alone will leave you with WTF-itis.
I have dyslexia and ADHD but I’ve had poor self confidence because of it. I had my IQ tested and it was high and I have found have found that if I don’t “get it “, then it’s because the person teaching it doesn’t do a good job of explaining it.
@@ale895 charts like that aren't really used now, but while studying they help to better learn the inner workings if you understand why the graph looks like this. Using software would be more akin to using lookup table, which is easier but doesn't help to "get" things
It's quite interesting to use the chart when working with antennas. However antennas are influenced by neighboring structures like antennas tuned to the same frequency. I have seen this myself as recent as today - change one antenna on my ham radio site and it impacts the other. A fence can also cause headaches.
@@ehsnils That's primarily due to the antenna's reactive field I'd have thought, when you place objects (especially conductive) in its near field it will impact the return loss of the antenna.
As a mechanical Engineer, EE stuff usually makes me want to run and hide, but this was fantastically explained and I feel like I learned something today!
@@jokerpandroidc9807 Join the Marines or the Navy-same school & VERY intense! Year long, but it is free! with housing, and food and exercise and guaranteed job offers upon graduation!! Not being sarcastic, it is a great school
This is one of those things that you hate with all you got until you magically understand it and it feels like dark magic. I vividly remember going through an entire transmission lines/antenna course without understanding anything at all. Then one day something snapped in my head and felt like the easiest thing ever. Once again, thanks youtube for bringing back some good memories!
different people different experiences, this was the easiest part with my teacher, but in the long run one remembers more about the parts you struggled with, not the ones that were easy, a little paradox, the people that pass everything might remember it, but the ones that struggled and passed will remember it more. But everyone will remember it enough to know where to find the answer if needed.
Had that happen. When I took EMTheory, our text book was really thin and had really limited explanations and worked out example problems. After getting a low B on the first test I went to the bookstore and got a Schaum's outline on EMTheory, and a couple others, and got a couple more EMTheory text books from the library. Between them, reading explanations of something I was absolutely NOT understanding, stuff would kinda meld together and often there would be that "OHHHHHH--That's EASY" moment. 'Course then the prof would throw a curve ball into things with some question on the test unlike anything we'd done or the other texts had and I'd be back to "I don't even know how to start drafting an equation for this".
a first year electrical and electronics engineering undergrad here. The analogy of rope used here really gave a clear insight on how signal actually travels are reflects back. keep it up !
It’s been so many years listening to “matching the impedance” in audio cables and inputs, but not understanding why… now this blew up my mind, thank you so much
I guess that's also the origin of the phrase "impedance mismatch" so often used in software engineering. It usually means two sets of abstractions where data are represented in different ways, so when you want to move it around between components you often find bottlenecks.
Same name, different phenomenon. In audio, you need impedance matching not because of reflections but because the end-stage and pre-amp input in the amplifiers are designed to work best for a specific load impedance, regardless of the characteristics of the cable in between (beyond the point where it is "good enough"). Having a bad match in inputs means the signal / noise ratio gets worse, in outputs it means more distortion and less output power. With EM waves, the cable is the key factor. A very expensive 50 ohm cable driving a 75 ohm antenna will do MUCH worse than a cheap 75 ohm cable driving that same antenna. In audio, a good cable will drive 4 ohm and 8 ohm speakers equally well. That is because the length of the cable is negligible compared to the wave length (15km). Any audio cable less than 1km long will have no problem at all with reflections etc. In accoustics however, you do have proper wave transmission and reflections. I.e. baffles and reflex ports have an acoustic impedance that needs matching with the room for optimum results, as well as the need for careful delay of signals to different sets of speakers to avoid interference.
My father was an electrical engineer and he explained the Smith Chart to me when I was still in grade school. I sort of remembered it but you really brought my memory back on it. Thanks. That made me feel all warm and fuzzy. :)
The Smith chart always felt like one of the most "mystical" cult-cargo-y things in my EE curriculum. This video explained it very well! would love a follow-up video describing how the chart is derived from first principles!
I am a student of English Literature Undergraduate, this does not relate to any of my subjects but I watch it anyway because how straightforward you are at presenting the topic
PE E level engineer, this was probably the most concise explanation of the Smith chart I've ever seen. This would of saved me a few hairs in school. Bravo
I'm currently finishing my PhD in mechanical engineering, and it's really fascinating the analogous behaviours you can see between different multiphysics domains, like resistance, capacitance and inductance producing similar dynamic effects as dampers, springs, and inertias. I used to work at a consulting company where among others things, we did fluid and pulsation analysis through compressor units. In the 1970s, before computers were powerful enough to do this kind of thing (so way before my time), the engineers would actually simulate the compressor system by building a little electrical circuit with R, C, and L components to represent the mechanical and fluid flow components, and then just let the circuit run. Way easier than building a mini-compressor on your desk!
Exactly. Resonance is a good example, as well. There's mechanical and electrical resonance. So many analogues, it makes this EE Techology major wish I had gotten a second major in Mechanical Engineering. In fact, I still go back to my alma mater and take CAD courses for free, and I enjoy it very much!
That process uses analog computers. Analog computers can be used to "solve" all manor of differential equations. I had fun with analog computers when I was studying EE in the sixties. This brings back great memories. I believe the principles described here are roughly the same as vibrations in mechanical systems. By extension, these principles can be applied as analogies in all kinds of systems like economic and social systems.
I’m an audio engineer, and I studied a lot of electrical/electronic engineering beyond my course work. This involved understanding the intricacies of amplification in venues of all sizes. This popped up in my exploration, and I didn’t find it scary at all-just as now, I thought it was one of the most brilliant graphical representation of a complex problem I’ve ever seen. I’d forgotten about it over the years, but seeing it again just made me smile. It’s absolutely astonishing how elegant our universe is.
Interesting you say that. I am also based in the same field- I work in broadcast with emphasis in audio. Let’s be real, we both know audio engineering isn’t actual engineering lmao. It used to be but unless you’re working stage or studio voltages, building a studio, or on antennae’s you barely ever have to worry about math. I always wish I would have done almost the reverse of what I did and worked harder in HS math and then done an undergrad in EE and grad in Acoustics or something similar like audiology. Don’t get me wrong I’m happy where I’m at, make enough to live comfortably, and will probably be moving into a broadcast engineering position within a couple years from the natural progression, but still. Could’ve been there sooner had I given a shit about math back in HS. Totally my advice anytime I have kids asking what they should do if they’re interested in the field. There is the argument it’s a dying field due to AI but I believe everything will always need ears and eyes so I disagree with those. Just hedge yourself in areas like broadcast and signal flow.
@@digital_urn9250I am also want to study in the university to be an audio engineer and I am very scary of the maths from that, but you said that barely maths are helpful, so I am little confused. However I am in another country where the AI aren't using in the world of audio for now. But anyways I want to study, so in less words i am confused and scary of the future PD: I am already making music and studying some basics concepts of mixing, production, frecuencias, sound design, stuff like that but I imagine is the 5% of you can learn in the career.
I remember in an undergraduate electrical engineering class where we were told AM stood for amplitude modulation and FM for “frankly” magic (to put it nicely). This is another case where the math is so involved and elegant and yet corresponds to a common real world application. Amazing.
When I first learned about this in my electromagnetics class, I wanted to beat the Smith Charts to a pulp. I did not understand it at all. The first time I looked at one, I thought I was looking at a freaking singularity!!!!
@@АлтайскийКазак to be fair, you basically only learned to read a number off the chart. To use that number to actually do something useful is an entirely different matter.
Partially right - at one end of the chart you have a singularity where the universe breaks down. If your design ends up there it's a sign that it won't work.
@@АлтайскийКазакhigh level college professors are notorious for not being able to actually explain anything. You can tell they are smart, but they are also horrible at effective communication. I'm also fairly certain that my textbook didn't actually have any information on how to use a smith chart and instead just gave us the formulas. And even if it is explained, you better hope your compass and ruler skills are up to the task or you will follow the steps correctly but still end up a wrong answer because the charts introduce imprecision.
I had an excellent professor for emag. Zach's explanation is as good as you will ever get. I had long since forgotten why the heck I even used the Smith chart, but this was an AWESOME refresher and now I'll never forget it!
I’m an echocardiographer. Believe it or not we have to take physics classes and pass a physics registry/licensing board before we can even sit for our echo registry. We learned a lot about wave physics, fluid dynamics, types of doppler, impedance, attenuation, etc etc. It’s really amazing how much of that stuff is relevant to this. So much of what we learned about sound waves applies to light just the same. Really cool.
I'm a EE, and while working for an earthquake simulation lab I learned that the same equation I use to calculate reflections in a coaxial connection is used by civil engineers to calculate the energy reflected by a building's foundation during an earthquake.
As a mainly self-taught AV technician for many years, not having been to college or university to study this line of work, this is a fantastic video to explain impedance matching! Thank you :)
@jordanrodrigues1279 I've been following the audio world/mindset/craziness for several years and I cannot believe the level of misunderstanding, myths, lies and underhanded marketing out there about speakers, cables, amplifiers and other "snake oil". I wish I was smart enough to test, document and present 100% truth in data to put an end to all of it. I really want a recording oscope and/or strip recorder to help me layout side by side proof of the nonsense myths and Golden Ear hype about audio products. Surely, you have met some folks like I have. Oh! The funniest one to me is the people who are worried about "skin effect" in speaker cables - hahaha! All the best, Kevin
Per Wiki, This amazing chart was independently proposed by Tōsaku Mizuhashi (水橋東作) in 1937,and by Amiel R. Volpert (Амиэ́ль Р. Во́льперт) and Phillip H. Smith in 1939. I liked the charts published by Cincinnati Electronics. They were already pre-normalized to 50 ohms.
When the prof showed this chart in the transmission line class, he made some mention about how this was a circle of summoning great power. No joke, a classmate just stood up and walked off class making the sign of the cross. it was definitely one of the moments that happened during my EE grad
What a moron, these natural patterns in electrical current and other places in nature literally represent God, it's the face of creation itself. Buddy needs to study the Masonic church and their symbolisms like triangles, eyes and other strange symmetry that does NOT occur in nature. Someone like that would funnily enough walk right into a Devils trap.
Good for him. If you think these frequencies don't have the capability to bring forth energies from other realms overlapping this one, you are sadly mistaken.
@@theurbanthirdhomestead Oh you're talking about CERN, but CERN has to do with particle physics. It's who uses it and how. Electricity and currents are just a tool. Like when you give a gun to a satanist he will shoot up a school, but give that same gun to a hunter and he will provide you with food.
EE here. This charts seems fairly intuitive and useful within its field. The worst thing i dealt with was 3-phase transmission analysis. I literally had to buy a new calculator for my final because my options were to either get a calculator capable of complex inverse hyperbolic trig functions or decompose it, run the analysis separately for the inverse hyperbolic trig, then recompose it at the end. The homework and exams were often just 1 or 2 questions and would take 3 or 4 pages of diagrams, derivations, and calculations to complete with no general formulas, rather processes to follow. I'm so glad the real industry uses steady state analysis everywhere outside dynamic modeling, because its even mechanically a thousand times easier.
This is where I am now. I'm in Electronics Engineering Tech, but a whole lot of Electrical Engineering curriculum crosses over to our own curriculum (For obvious reasons. We're doing a lot of the same things Electrical Engineers do, just on a much smaller scale.) I never thought I would end up doing math that took multiple pages of work to solve, but here we are. There is a silver lining though, when my wife looks at some of the problems I have to solve for homework and proclaims "That looks like Greek to me!" I get to respond "That's because it is!" and it makes everything worthwhile. Edit: I forgot to add that another positive is the fact that my shiny new calculator comes with python pre-loaded, so it's even more fun to play with than a normal scientific calculator.
I laughed out loud and shuttered at the same time remembering the one question final that took three or four pages and the entire hour, all it took was just one miss placed negative sign to screw up the whole thing. Oh, and no credit for the work only credit for the final answer. Good times.
I'm an amateur radio operator, and minimising reflections is important not only to improve efficiency, but also because reflections will fry thr RF amplifier on the radio at large enough ratios. We simplify this chart into a Standing Wave Ratio (SWR), and for most applications anything below 2.5:1 is good, though you can get away with 3:1 for lower power.
I’m not an engineer and these concepts never occurred to me before but they’re so interesting. Not sure why TH-cam recommended this to me but it’s honestly really cool to learn random new stuff. I never thought about electrical or sound waves and signals as having length that needed to be considered when designing electrical components
it's the same with light, think about the change of medium when it goes into water, some gets reflected, some pass and it is distorted, angles also affect in junctions, like when you dive into water, the wrong angle and you stop, in the case of electrical junctions it can make it heat up. BTW (about interesting things), if you want something extra interesting, look up superconductors and quantum lock, I find it fascinating.
I did RF double stub matching - long ago - but I couldn't do it now. Then I found out that a hydraulic pump driving a pipe uses the same Smith chart to do double stub matching for the sound waves.
The real question here is... How did they even come up with this chart? Just by looking at it you already wonder how the hell do you place such values. Amazing stuff
It's basically like the complex version of the unit circle, resistance is the component on the real /horizontal axis, where reactance is the imaginary/ horizontal component. Together the restance and reactance make the complex impedance. Since the imaginary parts of impedance (capacitance and inductance ) are frequency dependent and inversely related to one another as such, this nice and clean for one particular frequency, but gets more tricky when dealing with multiple frequencies.
it has a correlation with polar coordinates, but I would love to take an active class to know it. For reference, an active class is one where the teacher doesn't teach you directly, they are there to guide you, not to give you information, so, for example, they give you a problem, and some formulas that you have to use, the problem is designed in a way so you end up rediscovering the target formulas instead of the teacher giving them to you, you learnt the process that it took to get there, in other words, you end up learning how the hell did they came up with those formulas. Those classes are hard to create, but so fun to take.
Bell Labs came up with this in the 30s. There are only two equations, one for the constant imaginary and the other for the constant real circles. The real wild thing is what people plot on top of the smith cart, noise, efficiency, stability, output power, etc. based on a given range of impedances available at one port
I am a Ph.D. student in computer science, and this just brought back waves of trauma as an engineering major. Congratulations on teaching such a tough idea this simply. Would love to see more complex analysis based visualisations, which is the basis of Smiths chart.
I know EXACTLY what you mean, I got major in electronics and computer science myself. The fact people teaching that stuff at my university were probably the strictest of the strict there didnt help either : ^)
it's not a tough idea though! is that why you chose comp sci for grad school? 😋🫣 jk.i was a chem eng student and my EE class wasn't easy when I took it but made sense when I reviewed it some years later to soothe my wounded ego. I really psyched myself out over it all at the time 😑 ✌🏻
@john-ic5pz The idea is extremely simple, but taught to a 19 yr old without background in complex analysis, out of a slide and giving them the toughest questions to solve within a time limit is criminal. I work on probabilistic robotics, so hell no 😁😆.
Don't forget that Z is a function of F. So you have to make sure your evaluation is done for the particular frequency. If (like with a ham radio) you're going to be using frequencies within a certain range, or perhaps two bands utilizing the same antenna (like 1, 2, and 4 meter bands, harmonics of each other), you need to have some sort of impedance matching circuit to be able to load the antenna/transmission line appropriately to your chosen center frequency.
When you take a class, then often use that knowledge in your career for many years, it gets to be very familiar. If you never use it, you'll forget most of it. For instance, I don't remember that a transmission line typically has much resistance. What I seem to remember is that the 50 ohms is mostly capacitance, in magnitude dependent on frequency. What I do remember is that signals don't flow thru a cable at the speed of light; only about 1/3 that. Also, "ee-ee's" don't call themselves "ee-ee's". We are "double E's".
Brother I am a software developer and I know mostly nothing about electrical circuits other than the basics and you made this beautifully simple. Good job and keep it up.
Beautifully done, thanks. I'm a retired EE and this brought back an old memory from 45 yrs ago. When I was a young co-op student, the engineer I was assigned to gave me the job of determining the load resistance needed for some digital TTL transmission lines. This was a great learning experience for me, I had no idea until I watched the results on an o-scope. He could likely have simply told me what load to use but instead told me how to figure it out, a great mentor.
I was introduced to this in the navy durring Advanced Cal Training as a Metrology Technician and this one chart made all of the pieces fit together for me.
@@JgHaverty I was just thinking how this world really is a spiritual battle, and the ancient evil maritime spirits are actually being brought back by the world and its wicked ways, wars, violence, hatred, etc...
I am from IIT and i my self never saw so simple explaination. It is like i just whole my semester in front of my eyes. Trust me this guy is delivering gold !
I did Electrical Engineering and The Smith Chart was definitely not the scariest thing. The scariest thing would probably be Z-transforms, root locus analysis, stability criterion, PID tuning or secondary protection design.
I was a teaching assistant of some EE undergrads and got to learn this stuff. In the beginning I refused myself to read this chart, but once I knew how to use it, I started persuading every student to use it whenever possible!
You explained SWR better than most Hams I've seen. The only thing that would make this better is to explain how the resonance or lack of resonance contributes to the imaginary/reactive component of an antenna's impedance. Amazing video. You are one of my favorite youtubers.
@@pyropulseIXXI HI, That is what I did after the lecture and then understood it. My point was a TH-cam video did a better job of explaining it in 10 minutes than a University professor did in a one-hour lecture. btw. Thank you for your condescending advice on how I should fill any holes in my knowledge after a lecture - much appreciated!
@@pyropulseIXXI you'll definitely understand WHAT the Smith chart is in less than 2 minutes, but that doesn't mean you will fully grasp all its concepts. What OP means is that he gained a better understanding by spending less time watching youtube compared to an hour of college lectures, and most of the time, sadly, it's true
I finished my EE program this summer, but never got to learn how to use the Smith Chart, It was only glossed over during a lecture but thank you for this very clear explanation. I finally understand what it's all about! It really is much simpler than it looks!
navigating my way round the smithing chart was difficult in college as it was conceptually challenging, YT videos saved me big time for my HF/RF module. i learned that it wasn't required to flip the smithing chart to switch from lines of constant L to constant C, so grateful for this invention. could not do matched loads without it.
this is also what happens when light travels between two media with different refractive index, and a very similar graph (the acceptance plot) is used to design antireflective coatings
I graduated with my EE degree almost 10 years ago, and to this day the Smith chart is my go-to picture for scaring interns away from engineering. It's been very good for job security.
@@anonymousadam8950if they majored in engineering or physics and they’re in an engineering internship, it’s highly likely they could make it as an engineer. I think he uses it to scare interns away from RF engineering, specifically, as it cuts out a lot of the people who aren’t passionate or interested in the industry as much as they are looking for any job to make money
@@rv706 oh I agree. I doubt it actually scares anyone away. The smith chart isn’t even a scary concept, and I’m not an EE but I’d be really surprised if a 3rd or 4th year EE major doesn’t know what this is. They should be quite comfortable with all related math and physics concepts at that point, even if they haven’t seen it explicitly before. Algebra and calculus in the complex (w/ imaginary numbers) domain is the bread and butter of EE math. I think the original commenter’s “weed out” method is really out of touch, and more so some sort of delusional ego boost for them. The only rationalization I can think of would be if he’s actually talking about electrical engineering technician interns, as they would be 2 year degree seekers/graduates with far less experience and depth of knowledge on the theory behind EE. Then it would be borderline cruel.
When I went to Electronics School we learned this as Standing Waves. We didn't use the chart, we learned how to measure and trim for it. It was a 2 year Electronics Technician course that paid me back in spades. Back in the mid to late 70's.
Smiths charts weren't the scariest, at least I understood the process and results. Laplace transforms though, now those were scary and I never really understood when we'd ever use them. Of course I haven't needed to use either in ~40 years since. RF really is the dark arts of electronics.
Laplace transform is indispensable for control theory and system analysis - and (just like any other subject) not that hard to understand once you understand it. Yes, the recursion is intended.
I used to fear Laplace in Diff eq. But then in Circuits Analysis 2 I learn it was my best friend in RLC circuits. Trying to do any work on an RLC without LaPlace was just shooting yourself in the foot. It was many times more complicated and longer process. While using a laplace, adding all components then reversing the laplace is just a fraction of the process. With the table you can do practically most scenarios, otherwise a good calculator can help you with it (TI Inspire Cas ii) when programmed right or if you know the equation (integral) process. To me was like fearing Polar equations in calc2, but in calc3 were the easiest way to solve certain equations. Although the point of engineering was never 'how to use tools' (that is something you have to develop on your own), it is When to use them. Thankfully as you said, IRL work is much detached from those processes. (Granted, Statistics and probability is the most important course any engineer should take no matter how detached it is from the essensance of their concentration). - Computer Engineer
laplace transforms are easy; I think people don't understand this stuff because they view math is a tool rather than the fundamental thing to all of existence I double majored in math and physics; math people thought physics people were too gung ho and sloppy with math (which I agreed), but were too stuck in their generalizing ways and would be very shallow and general. my entire purpose was to get a PhD in theoretical physics, combining the best aspects of math and physics into one
with laplace in control theory, divide output function over input, laplace transform, project result on unit circle in complex coordinates. your operating point lies outside unit circle -> unstable.. as far as i remember
This brings back memories of my 45 years in aerospace engineering. I worked on radars and telemetry systems at the big aerospace companies in the LA area like Hughes & Raytheon. It was a lot of fun.
Hi, a quick question from an undergrad student here. I'm studying a double in EE and Physics, do think my degrees are a good skillset if i'm looking at pursuing a career in aerospace?
As an RF engineer much of product tuning is this very thing (impedance matching). We used metal tabs on microstrip transmission lines, as well as dielectric & ferrite chips.
I loved Smith charts! They were the most intuitive, straightforward thing I learned in EE. Beautiful combination of real and imaginary numbers. Nothing scary at all about these...
I work in sales, and I watched the whole thing. Holy s*** youre a great teacher. I know nothing about the EE field and this kept me engaged and I understood a lot of it by the end. Kudos friend
I learned to use a Smith Chart and circular Smith Chart calculator 57 years ago when vacuum tubes were still being used, and later worked with air traffic control radar systems in the early 1970s. Think of a klystron in a microwave oven that generates pulsating waves of electrons that get funneled down a wave guide and out into an enclosed oven cavity. The oven cavity is the terminating impedance of the wave guide, and when empty it has low resistive impedance. Low resistive impedance means a lot of energy would be reflected back into the wave guide, back toward the klystron. This reflected energy could overheat and damage the klystron, which is why they say, "don't operate the oven empty." When energy-absorbing items are placed into the oven cavity, the resistive impedance increases and less energy is reflected back, allowing the oven to do its job. The Smith Chart and calculator were likely invented and perfected to support the development of radar systems prior to and during WWII. The microwave oven is an offshoot of radar research and was invented by accident in 1947. In a radar system the energy from the hollow wave guide is blasted out against a reflective dish and out into the air. The energy-absorbing air acts as the resistive impedance to the energy-producing klystron.
Very nice how you described the Z of an empty oven as a termination to the transmission line. I thought it would appear as an open, high Z. When you put a metal object in the oven, does that increase or decrease the load Z? We know about the sparks and such and an even more likely situation that the magnetron could be damaged from reflected power. I have considered mounting a microwave oven magnetron at the focus of a parabolic dish and modulating the anode voltage for AM at 2.4 GHz. I have not done it yet but I still think about it sometimes. I have wondered how the magnetron would react into the dish and what load it would see if placed at the focus. I figured it might appear as an open or at least high Z. Might make for an interesting EME (moon bounce) project for amateur radio. Just curious.
As a lowly Ham operator I have often had questions about transmission line/antenna impedance matching and this video was so simply explained it quite figuratively blew me away.
I was a electrical engineering technology major rather than EE proper, and also took more of the digital route- so i hadn’t seen this chart before. Awesome video and makes me want to get back into books and study more analogue haha.
Having learned that at the age of 15/16 in engineering school, over 25 years later i still find the Smith Diagram an incredibly elegant and "simple" help for dealing with impedance matching. (Hope impedance matching is the correct term in english, as i didn't learn that stuff in english as it's not my native language) And i have the utttmost respect for anyone like Phillip Smith who can come up with something ingenious like this diagram.
@@annieZOK 😁😁😁 -> engineering schools here usually are from age 14 to 19 if you pass all exams. -> 5 school years of 40 hours of school per week. (not counting homework and studying for exams) 9 of the 40 were practical work in workshops. So in my case: on a lathe, mill, learning to file precisely, soldiering, circuitboard etching... And of the remaining 31 hours 80% were calculating things. (the 20% are languages, sports, ethics and a tiny portion of "law and citizenship and finances" There is also the possiblity for "grown ups" to do engineering school as "evening school" after their workdays, but i am glad i did it right after mandatory school.
What country are you in? Your education system sounds like it takes good advantage of the energy and curiosity of youth, getting them involved in career/higher level courses earlier than they usually are here in the US. Our "high school" programs can vary widely from state to state, even district to district, some doing a good job at preparing students with essential skills to move on to college or a trade certification, others not even graduating students capable of essential communication or math skills. I keep hoping that the decision makers will look at what's working elsewhere.
@@erinmcdonald7781 Austria. And we are the only ones to my knowledge with engineering schools like that. Sorry in advance, this is going to be a long one, trying to explain how it works here: We have something similar to elementary school from age 6-10 (4 schoolyears). From age 10 to 14 there was, what would translate to "main school" and today is called "middle school". (4 years) Mandatory education is 9 schoolyears. So either one has to do 1 "polytechnikum", or go on to a "higher school" that takes longer anyways. People who decide for only the 1 year only, after said year, then usually start an apprentice ship (at age 15) to learn crafts or trades. These apprenticeships take place at companies who use such crafts/trades people and they train them in the practical work. And for 2 months or so each year they attend craft/trade schools. (so they learn the theoretical needs for their craft) The apprenticeships take between 3-4 years depending on the craft or trade they learn. (carpenter, mechanic, cook, hairdresser...) After their final exam, they are considered "craftsperson" and can be employed as such. If after their final exam they want to step up their game another stop, they can attend (on their own money this time) further courses and attend a more difficult exam which makes them "Meister" (master of their craft, not to confuse with the university study title Master which is used in it's english wording) During an apprenticeship the apprentice gets an "apprentice compensation" (so the salary of an apprentice is a little lower than that of an approved craftsperson) If one opts for higher education instead of an apprenticeship there are said "higher schools". And of those there are 2 types: 4 schoolyears ones and 5 school years ones. The 4 year ones are called "allgemeinbildende höhere Schulen" would translate to "higher schools for general education". (they usually have a 3rd language, and arts etc.) And the 5 year ones are "berufsbildende höhere Schulen" which translates to "higher schools for professions/crafts education" And for a better understanding, these are the engineering schools. (they produce engineers so some of us call them engineering school) Cause as a student of these you learn around 80% of what a university student in the same field learns, but you spread it out over 5 years and you get more practical training in the workshop. (and you start earlier in your life) Both of these higher schools have final exams. But the 5 year ones are a "bit" harder iif i may say so. To get a little taste of the final exam of an engineering school at the turn of the millenium, mine consisted of: 5 hours of written german language exam 40 hours of project work exam (getting a task, then calculating, drawing, programming, making parts-lists... without talking to your classmates who are in the same room, and only using books and tools you brought in on the first day and no finished projects among them.) -And lastely oral exams in 4 school subjects. My four subjects were -measuring technology, -information technology, -electronics and digital techology and -english. These oral exams were in a way that you can pick between two topics in each subject. (out of all the stuff we learned in the 5 years prior), then get 10 minutes of preparing and then have to hold a presentation in front of a commision about the topic you picked. And of course answering possible questions of the commision. And passing such final exams in either higher school means one is allowed to study at a university. But with the engineering schools you also are trained in a profession and can start working for a company, or found your own. Companies all over the world do hire such people. Former classmates of mine were working in Brazil and the UK from what i learned at my last class reunion 5 years ago) Sometimes as middle ground (translater) between workers and uni engineers, but often also instead of uni engineers. Btw.: those engineering schools have a long tradition here. The engineering school i attended had it's 100 year anniversary at it's current location 2 years ago.
Let us know which country you learned this at… I agree with @erinmcdonald, it’s great to start teaching young, energetic minds about the more complex concepts of the subjects they’ll take in university/college. Thanks.
2:20 This is probably the point where any non electrical engineering student stopped. "Why do you mean complex numbers? Why would you use a complex number in a circuit?" 😂😂😂
Wow, thank you for that! As a EE undergraduate and an amateur radio operator I’ve seen the problems of SWR and in feed lines to antennas, but never could visualize the reason why your can burn out a radio from that reflected energy.
@@josho9910 my first few years of college were extremely challenging, so I went in with the mindset of, “I’m not going to fully understand everything, and will be taking home B’s,” which may have been more mentally healthy, but setting low expectations for myself just created a self-fulfilling prophecy. Go into classes and units with the mindset of, “I’m going to become an expert in this field. When this class is over, I’ll be able to explain what I learned to a fellow engineer, my parents, and a child.” That mindset will take you far.
@@trinity8675309beautiful reply. Love the 3 audiences to imagine giving an explanation. Only being able to explain to any strict subset of the 3 shows you lack understanding.
Good lord. At my uni the highest mark on our Telecoms class final was like 62%, and that was an open book exam. That was the hardest class I did at uni by far, and I'm convinced that it's all magic and that telecom engineers are wizards.
When I was a young tech, a great engineer that I worked for taught me about Smith charts. "Oh, I get it" seemed straightforward when he explained it. But in the intervening years I really had no use for them, really, and now I probably would be baffled again. At least now we have affordable instruments that can make it easy to plot one out.
That went totally over my head but I was curious...at first... then I got excited especially when he started to explain how the cone thing works😊 Pretty interesting stuff
I was expecting some abstract physics thing about infinity that would cause existential dread... but the idea of being responsible for understanding and using this material in a real-world engineering context is incredibly intimidating haha. That said, this is extremely well explained and informative!
Thank you for this helpful video, I am a communication engineer and I think smith chart is misrepresented as being “scary” but in fact is simple and helpful tool that doesn’t require a lot to understand in my opinion
I remember struggling with the smith chart at first in college. I would have loved to have a video like this as an introduction - definitely would have saved me a few headaches.
As a civil engineer this video was a nice challenge to follow along and recall the physics and mechanics that correlate. And Btw when you have highlighted in purple the Smith diagram it looked the same as Mohr circles that describe the envelope of a certain shape or material that can describe the maximum tension states in the basic stress planes.
Just learned about this in circuits 2! Power companies utilize a circuit with incredibly large capacitors in parallel to create a false j0, therefor no visible impedance (capacitors are measured in negative j values). This is not done with our homes because we do not typically have to many inductors in our houses, but factories use motors all the time! Motors can actually give the same effects as inductors since it utilizes electromagnets, which is what inductors literally are.
I'm an elevator mechanic that loves physics. I can see how this plays with variable frequency motor control drives, and have a deeper understanding of harmonic resonance thanks to your video. Stubbing a transmission line is really cool, I'd love to see a video on it from you. Thanks for the learning!!!
Nope. It took multiple generations working on handed down knowledge, each adding something, to get here. Even Einstein was working off existing knowledge men before him noted down.
Very interesting, I remember learning Transmission Line Theory in some EE course in college, but I don’t remember learning this chart or how to match impedances
Beautifully explained. I’m an MSEE trained in semiconductor design, but now running a software company. I’d lost touch with smith charts long back (right after my BSEE) due to my career path. This set me straight, getting in touch with my fundamentals. Thank you! 🙏
I remember this. We had to se a very similar chart when adjusting poles for the radio antenna in the Marine Corps back in the day. The radio ops would just memorize the frequency and poles, then when something didn't work right they called me and I had to use this chart thing. I used to try and explain it but everyone just stared at me. In the end I told them it was just basic magic, and they rather believe that then the actual science that went into it.
It's more accurate but less intuitive if you think about the stub as being a third, much shorter rope attached to the thin rope, that resonates just so and cancels out the reflected wave from the junction. From far away, though, the "one big rope" analogy is good enough.
Bravo! Probably one of the best and simplest articulation of a complicated phenomenon. 🙌"If you cannot explain something in simple terms, you don't understand it." - R. Feynman
Zach, an idea for the next video: why a complex, non-physical value is used to measure impedance. I think you already had one about Laplace transform. FWIW, I've seen a slide rule for high-frequency EE. It was Japan-made, I believe. It also had a scale for impedance matching. I was 15 or so, the stuff flew way over my head! I only remembered the words, “impedance matching.”
I second that. I received my BSME in 1984, and to this day I still don't understand "imaginary" numbers. I mean, you can't see or touch them, so how can they "exist"?😢
@@markfreeland1027 Glad you have no issues imagining infinitely many rationals between 0 and 1, and _a larger_ infinity of reals between 0 and 1, _exactly as many_ reals in this “small” interval as there are reals between ±infinities, so it's not in facts “small:” it's as large or small as those between 0 and 10¹², or ‒0.0001 and ‒0.001, or ‒10¹⁰⁰ and 10¹⁰⁰. Good for you that you're getting mental hiccups only from imaginary numbers! :)) Seriously, my point was very, very different. When we talk about rationals, reals, complexes we just mean a set of objects satisfying axioms that define an object called the _field._ The main idea is that we can add, subtract, multiply and divide them, and every time get another object (a number) from the same field. Also, there are special numbers 0, such that 0+a=a+0=a and 1, such that 1×a=a×1=a. Division by 0 is usually excepted, although complex numbers may be augmented unambiguously by a _single_ infinity, a limit of a circle of infinite radius from the origin of the complex plane. Reals cannot: is 1/0 +infinity or -infinity? oops. Positive reals can, tho, and this is also useful in other areas. In complexes, we get poles when “dividing by zero,” Consider the transfer function of a filter: it's a ratio of 2 complex-values polynomials, where roots of the numerator are zeroes, and roots of the denominator are poles. These zeros and poles characterise the filter completely. Fields are formed not only by numbers: there are also vector fields, also very useful in physics: say the field of gravity, characterized by the vector, a force acting on a small test particle, everywhere in space. Fields are formed my square matrices of given size, and in quantum mechanics, matrices with complex elements are very useful. Complex numbers are extremely useful in physics, not speaking of maths itself. There are 4 types of numbers that form a complete algebras: reals, complexes, consisting of 2 reals (a+bi), quaternions (4 reals, a+bi+cj+dk, where are 3 “imaginary” units i,j and k), and octonions, of 8 reals each. Quaternions are very useful in computing spatial relations and projections to the plane of view, and chances are, if you play a first-person shooter game, it's maths is built on quaternions. Octonions find their use in the description of the strong force, which holds protons and neutrons, particles of 3 quarks each, together. This is a very complex quantum theory. Complex numbers are just everywhere! Watch 3blue1brown videos, and you'll grok them. The beauty of them is that they can be looked at in two ways. You can define a complex number by a pair of reals as (a+bi), a point (a, b) on the complex plane. You can multiply them as normal polynomials: (a+bi)(c+di) = ac + bci + adi + bci². i²=-1 by definition, so the result is =(ac-bc)+(bc+ad)i, also a complex. But in EE, another representation is more useful. Since a complex is a point in complex plane, with perpendicular axes (horizontal axis is traditionally taken to be real), the line from the origin to the point representing the number defines a rectangle, splitting it into two equal right triangles. By Pythagoras, the length, or _absolute value,_ or magnitude of a complex number z, is obtained from z²=a²+b². So you get a circle with the radius z, where all complexes of the same magnitude |z| lie. To fix a specific one, you need also the second number. Most useful one is the angle φ, counted counterclockwise from the positive direction of the real axis (usually, horizontal, left of origin): tanφ=b/a. This angle fixes one number on the circle _down to an arbitrary multiplier_ k×2π, k integer, i.e. ±k full circles around don't change anything. This is called the _argument_ in maths, but in EE, think of it as the _phase,_ and the magnitude as the _amplitude_ of a sine wave. This is the most useful representation in EE: phase is also defined down to k×2π. Instead of writing z=A×(cos(ωt+φ₀)+i sin(ωt+φ₀)), where A is the amplitude A=|z|, which is a mouthful, use Euler identity and write z=A×exp(-i(ωt+φ₀)). Multiplication and division of exponents is much easier than that of polynomials! The usefulness of complex numbers comes from the Laplace transform. You take a _real-valued_ signal x(t), and the transform, which is one-to-one, spits out a complex-valued function z(s). What is s? it's a complex _non-physical_ number, just a parameter to find a point in the transformed space.The EE maths magic that happens is, inductances and capacitances are transformed into simple linear components that can be multiplied and divided (resistances remain real). Your AC signal is processed by a circuit of L and C that have a complicated behavior in time domain. But in the transformed space, they are simple polynomial ratios, easy to manipulate! After you did all the simple maths, you may do the reverse transform and get the output signal. You also very easily compute the group delay, spectrum, frequency-dependent phase shift, and so on. It's hardly computable in sinφ+icosφ form: you'll run into stuff like sin(arcsin φ+arcsin ψ), which is nigh impossible to work with. So the essence of the trick is (a) use one complex number instead of two reals, namely amplitude and phase, and (b) use a special transformation into _purely mathematical,_ non-physical space where analysing the signal w.r.t. capacitances and inductances is much easier. My *main point* is not that the s in the Laplace domain (usually called s-domain) is complex. It's fine, you use normal algebra to work with these complex number. The main point is that anythings we measure: time, distance, velocity, force, voltage, current, just anything at all is real-valued. Your voltmeter reads 5.5V. You never read 5.5+2.5i volts, that would be nonsense! Yes, the wavefunction Ψ of quantum mechanics is complex. But, first, we don't _observe_ it, and second, its phase has no consequences at all, only its squared magnitude, which makes physical sense, has; the phase cannot be discovered in any real-world experiment. It's a maths crutch for computation, which doesn't correspond to anything in reality. So nothing-really nothing at all in the real world-is complex-valued! This was the essense of my request to Zach. Complex numbers occur only in applied maths devices invented to make our computations easier. But when we are back to the physical, real reality, everything is real-valued. This fact is at least notable to me, if not awesome. Physics is written in real numbers, real-valued vectors, real-valued tensors and other real-valued stuff. We use a lot of other, mathey objects-in physics, mainly complex numbers-that make computation easy, but always start and end with reals only. This is the gist. We use complex numbers so much and so naturally that we forget that they never arise from physical measurements in the first place. This distinction must be made very clear in communicating science. A deeper mystery is that, weirdly, we can use real number measurements to build theories that predict other real-valued measurements-i.e., describe the world in real numbers. Is it a property of (a) real world, (b) real numbers of (c) our mind inventing theories? “The Universe is complex just enough to produce physicists, yet simple just enough so the physicists can understand it.” Isn't that… uncanny? But that's a whole different can of worms.
I think I discovered the catalyst for learning and understanding. It’s passion and how much you are interested in a topic. Making you wanting to understand a topic very badly and passionately. If this isn’t present, forget about teaching anyone something they don’t care about. They will most likely fail. Passion and interest allows a student to listen deeply to understanding instead listening to hear. It also overpowers the fear of failure. If you care deeply about a subject, failure won’t discourage but will be used as fuel to get to an answer or understanding. I think this is what formal education systems have disconnected with the student to learning/knowledge paradigm. A teacher that tries to instill fear and negative reinforcement instead of instilling passion, wonder, curiosity in their student will almost always fail in teaching. There’s is a high correlation between passion and success or understanding. I remember learning high school physics and calculus because and being bored so I retained nothing and was a average student. I didn’t pick that that is what I wanted to learn with passion. Now after all my schooling, I find myself researching and learning about things I’m more passionate and curious about. The result is that I am understanding them with ease. History, Science, technology etc. have become so interesting to me as an adult such that now they are much easier to grasp and comprehend. The missing variable was passion and desire. Previously I didn’t understand or care to understand because they said I “MUST” learn but now I understand and learn so easily because I “WANT” to learn. Took me way to long to understand this concept.
Despite multiple semesters covering all of the complex number math involved, nothing I had in college explained the PURPOSE of the math and the intuitive implications resulting from the math. FANTASTIC animation and explanation.
Subscribed! Great video. Really appreciate the clear and simple way you explain the real and imaginary parts of the wave properties and the use of symbol j instead of i. Lots of physics videos and lessons miss properly describing these key elements and leave learners in a difficult position. Great job.
A butterfly flaps it's wings, and the universe breaks down from computational complexity. This universe is inside the engineer's head as he tries to understand the Fourier transformations need to calculate it's echoes.
I imagine he means “scary” as in intimidating to a student approaching the material for the first time. I think he does college tutoring/instructing professionally.
I'm an accountant. I feel like I walked into the wrong classroom but stuck around because the teacher was so good. I actually understood this very well; thank you.
Are you in public? If so how has it been
Think of this that way: How much money goes into the business and how much of that money is reflected and you want to minimize reflected money
Benjamin Franklin discovered you can account electricity the same way as money, with positive and negative. money is the symbolic energy of an economy
Lol. Don't hype yourself up. Watching a video without jargon words and writing a comment that you understand doesn't mean you are smart. Try doing application and you'll never want to pick up an oscilloscope again.
@@shayorshayorshayor you sound like a crab in a bucket
I am an electronic engineer who studied in the best engineering school in my country. I've never had an explanation so good in my transmissions line course while in college. Simply amazing!
Yeah, your country is terrible at education.
Should have attended DeVry, we studied them extensively in RF circuits class.
@@firstnamelastname9215 Your country is plummeting in the ranks I wouldn't be so quick to jump the gun on being a dork lol
@@publicalias8172 lol we could take over your country right now if we wanted to in one day
@@firstnamelastname9215 ok kid, go back to the corner, there's crayons over there, adults are talking here
ok but as an EE student when you DO use the smith chart and it works, you feel like a wizard and you save a lot of time
It's a nomograph! Computers before computers!
Not gonna lie, im an electrical engineer (power systems) and never encountered smith chart except through the internet.. we just did the transmission line theory and calculations by hand. i feel like branching transmission line grids and stuff like bewley diagrams become hectic and complex very easily, so it might lose utility
@matteod2567 im still in college and our teacher made us use them in class, he did say we'd probably never see them again though. the chart is pretty slick when it works!
If you're going to do RF work, you need to make the Smith Chart you're friend. Even circuit simulators like TopSpice can show you results on a Smith Chart. Getting RF signals around anywhere on a board, or to an antenna or load REQUIRES a good matching impedance. Being able to navigate around one helps you understand what parts you need and where to put them when you're designing your circuit, and can even help you debug your circuit and find problems when your prototype doesn't work.
I don't use it for my current job, but I did for my last one, in the design of a 2GHz satellite receiver, and for matching a 600MHz transmitter to a carefully constructed matching circuit that powered a small quartz tube to generate LOTS of UV light.
Good luck with your studies!
@Cynthia_Cantrell yeah even the network analyzers we used in class show their results on a smith chart, and by seeing how the curve moves around you can get a lot of info out of it really quickly. it's what I love about EE, yeah there's complicated math but you can see that math working in the real world
I'm not a radio engineer, I will probably never need this in my entire life, but thank you, it is very helpful
Last semester i understood how this works and I failed the exam, this semester i just used it and passed
@@jackpeterson6670 wut?
@@vitoremanuel5349 The Smith chart doesn't tell you why or how the signal gets reflected, only how big the reflection will be.
@@jackpeterson6670relatable
@@jackpeterson6670😢
I am an electrical engineering phd candidate and I have to say that this is a phenomenally explained video! Your use of animations were amazing!
i hated the big red arrow that went around the middle of the chart 4:38, but then 4:45 shows what to look for, the rest of the animations were great
@@XDbored1WHAT IS E=MC2 is taken directly from F=ma, AS TIME is NECESSARILY possible/potential AND actual ON/IN BALANCE; AS ELECTROMAGNETISM/energy is CLEARLY AND NECESSARILY proven to be gravity (ON/IN BALANCE); AS the rotation of WHAT IS THE MOON matches the revolution. GREAT. Gravity is an INTERACTION that cannot be shielded (or blocked) ON BALANCE. It ALL CLEARLY makes perfect sense ON BALANCE. Consider WHAT IS THE EYE ON BALANCE. GREAT !!!
By Frank Martin DiMeglio
Is the Smith chart always used in electrical circuits or only when carrying information?
@@jrfcss its used to calculate losses to reflection so you would want to use it for anything that is either high frequency signalling or high power transmission, most DIY stuff probably doesn't need it but people still do impedance matching for like custom modded speakers with HIFI audio.
@@XDbored1 thanks I never thought about that
Educating is like comedy. It is all in the preparation and delivery that provides for the audience either “getting it” or not and this was exceptionally presented in an all relatable fashion that did not require people knowing “inside information”. Nice work.
I don’t get it.
@@mikehammond7277 don't worry you are not alone😃
@mkehammond7277 I'm an electrical engineer and use this almost every day and while I "get it" it took me months to grasp it. Don't beat yourself up this is EXTREMELY difficult to understand
@@skyking6989 If you understand the basic effects of R, Lx and Cx and the effects of object form on the same then you get it, minus the formulas. The formulas alone will leave you with WTF-itis.
I have dyslexia and ADHD but I’ve had poor self confidence because of it. I had my IQ tested and it was high and I have found have found that if I don’t “get it “, then it’s because the person teaching it doesn’t do a good job of explaining it.
As an RF test engineer, I have to say this was beautifully done! I used to struggle with smith charts in college, wish I was able to see this then!
Hi, I was actually thinking if going down a career path similar to this, would you mind giving me a brief overview of what you do day to day?
What’s your take on microwave auditory effect?
@@ale895 charts like that aren't really used now, but while studying they help to better learn the inner workings if you understand why the graph looks like this. Using software would be more akin to using lookup table, which is easier but doesn't help to "get" things
Pax River?
@@siphonlx don't do it
I am an engineer with 15yrs experience and I still learnt a lot about impedance matching.
This is the best explanation of it I have seen
It's quite interesting to use the chart when working with antennas. However antennas are influenced by neighboring structures like antennas tuned to the same frequency.
I have seen this myself as recent as today - change one antenna on my ham radio site and it impacts the other.
A fence can also cause headaches.
It really was the best explanation I have ever seen.
@@ehsnils yeah we get these issues with metal detectors too out in the bush, nearby detectorists and powerlines mess it all up
Yeah, basic science is TERRIFYING. Scared. Not using electricity anymore.
@@ehsnils That's primarily due to the antenna's reactive field I'd have thought, when you place objects (especially conductive) in its near field it will impact the return loss of the antenna.
As a mechanical Engineer, EE stuff usually makes me want to run and hide, but this was fantastically explained and I feel like I learned something today!
This actually works in mechanical vibration too. Just different remedies.
This is a way better explanation than I ever got in my electromagnetism class
way better explanation
Stuff of nightmares.
how to get in such a class?
@@jokerpandroidc9807 Join the Marines or the Navy-same school & VERY intense! Year long, but it is free! with housing, and food and exercise and guaranteed job offers upon graduation!! Not being sarcastic, it is a great school
@@jokerpandroidc9807 it's a requirement for electrical engineering
This is one of those things that you hate with all you got until you magically understand it and it feels like dark magic. I vividly remember going through an entire transmission lines/antenna course without understanding anything at all. Then one day something snapped in my head and felt like the easiest thing ever. Once again, thanks youtube for bringing back some good memories!
Yes!
different people different experiences, this was the easiest part with my teacher, but in the long run one remembers more about the parts you struggled with, not the ones that were easy, a little paradox, the people that pass everything might remember it, but the ones that struggled and passed will remember it more. But everyone will remember it enough to know where to find the answer if needed.
The same thing happened to me with reading schematics. One day it just popped and a whole world opened up to me.
Had that happen. When I took EMTheory, our text book was really thin and had really limited explanations and worked out example problems. After getting a low B on the first test I went to the bookstore and got a Schaum's outline on EMTheory, and a couple others, and got a couple more EMTheory text books from the library. Between them, reading explanations of something I was absolutely NOT understanding, stuff would kinda meld together and often there would be that "OHHHHHH--That's EASY" moment. 'Course then the prof would throw a curve ball into things with some question on the test unlike anything we'd done or the other texts had and I'd be back to "I don't even know how to start drafting an equation for this".
@@alenasenie6928 Might have something to do with how stress effects memory creation
a first year electrical and electronics engineering undergrad here. The analogy of rope used here really gave a clear insight on how signal actually travels are reflects back. keep it up !
It’s been so many years listening to “matching the impedance” in audio cables and inputs, but not understanding why… now this blew up my mind, thank you so much
I guess that's also the origin of the phrase "impedance mismatch" so often used in software engineering. It usually means two sets of abstractions where data are represented in different ways, so when you want to move it around between components you often find bottlenecks.
Same name, different phenomenon. In audio, you need impedance matching not because of reflections but because the end-stage and pre-amp input in the amplifiers are designed to work best for a specific load impedance, regardless of the characteristics of the cable in between (beyond the point where it is "good enough"). Having a bad match in inputs means the signal / noise ratio gets worse, in outputs it means more distortion and less output power. With EM waves, the cable is the key factor. A very expensive 50 ohm cable driving a 75 ohm antenna will do MUCH worse than a cheap 75 ohm cable driving that same antenna. In audio, a good cable will drive 4 ohm and 8 ohm speakers equally well. That is because the length of the cable is negligible compared to the wave length (15km). Any audio cable less than 1km long will have no problem at all with reflections etc.
In accoustics however, you do have proper wave transmission and reflections. I.e. baffles and reflex ports have an acoustic impedance that needs matching with the room for optimum results, as well as the need for careful delay of signals to different sets of speakers to avoid interference.
here in Brasil we call it "impedance marriage", I never forgot it because I find it kinda funny
My father was an electrical engineer and he explained the Smith Chart to me when I was still in grade school. I sort of remembered it but you really brought my memory back on it. Thanks. That made me feel all warm and fuzzy. :)
The Smith chart always felt like one of the most "mystical" cult-cargo-y things in my EE curriculum. This video explained it very well! would love a follow-up video describing how the chart is derived from first principles!
I am a student of English Literature Undergraduate, this does not relate to any of my subjects but I watch it anyway because how straightforward you are at presenting the topic
What shall we do give you a medal
@@maalikserebryakov Dildo for you perhaps?
PE E level engineer, this was probably the most concise explanation of the Smith chart I've ever seen. This would of saved me a few hairs in school. Bravo
They have other uses. That's just the most common.
would HAVE
@@peterheinzo515 What do you mean "would have"? Seems like you imply they haven't been used for anything else.
@@dbtest117 „would of“ is wrong.
Maybe it sounds easyer because you already learned it in school XD
I'm currently finishing my PhD in mechanical engineering, and it's really fascinating the analogous behaviours you can see between different multiphysics domains, like resistance, capacitance and inductance producing similar dynamic effects as dampers, springs, and inertias.
I used to work at a consulting company where among others things, we did fluid and pulsation analysis through compressor units. In the 1970s, before computers were powerful enough to do this kind of thing (so way before my time), the engineers would actually simulate the compressor system by building a little electrical circuit with R, C, and L components to represent the mechanical and fluid flow components, and then just let the circuit run. Way easier than building a mini-compressor on your desk!
Exactly. Resonance is a good example, as well.
There's mechanical and electrical resonance. So many analogues, it makes this EE Techology major wish I had gotten a second major in Mechanical Engineering. In fact, I still go back to my alma mater and take CAD courses for free, and I enjoy it very much!
They were making analog simulations. Basically an analog computer/calculator model.
That process uses analog computers. Analog computers can be used to "solve" all manor of differential equations. I had fun with analog computers when I was studying EE in the sixties. This brings back great memories.
I believe the principles described here are roughly the same as vibrations in mechanical systems.
By extension, these principles can be applied as analogies in all kinds of systems like economic and social systems.
I always appreciate digital systems emulating analogue. Humans can't unlearn the world.
I’m an audio engineer, and I studied a lot of electrical/electronic engineering beyond my course work. This involved understanding the intricacies of amplification in venues of all sizes. This popped up in my exploration, and I didn’t find it scary at all-just as now, I thought it was one of the most brilliant graphical representation of a complex problem I’ve ever seen. I’d forgotten about it over the years, but seeing it again just made me smile. It’s absolutely astonishing how elegant our universe is.
Interesting you say that. I am also based in the same field- I work in broadcast with emphasis in audio. Let’s be real, we both know audio engineering isn’t actual engineering lmao. It used to be but unless you’re working stage or studio voltages, building a studio, or on antennae’s you barely ever have to worry about math. I always wish I would have done almost the reverse of what I did and worked harder in HS math and then done an undergrad in EE and grad in Acoustics or something similar like audiology.
Don’t get me wrong I’m happy where I’m at, make enough to live comfortably, and will probably be moving into a broadcast engineering position within a couple years from the natural progression, but still. Could’ve been there sooner had I given a shit about math back in HS. Totally my advice anytime I have kids asking what they should do if they’re interested in the field. There is the argument it’s a dying field due to AI but I believe everything will always need ears and eyes so I disagree with those. Just hedge yourself in areas like broadcast and signal flow.
@@digital_urn9250I am also want to study in the university to be an audio engineer and I am very scary of the maths from that, but you said that barely maths are helpful, so I am little confused. However I am in another country where the AI aren't using in the world of audio for now. But anyways I want to study, so in less words i am confused and scary of the future
PD: I am already making music and studying some basics concepts of mixing, production, frecuencias, sound design, stuff like that but I imagine is the 5% of you can learn in the career.
I remember in an undergraduate electrical engineering class where we were told AM stood for amplitude modulation and FM for “frankly” magic (to put it nicely). This is another case where the math is so involved and elegant and yet corresponds to a common real world application. Amazing.
When I first learned about this in my electromagnetics class, I wanted to beat the Smith Charts to a pulp. I did not understand it at all. The first time I looked at one, I thought I was looking at a freaking singularity!!!!
It might have been the way they taught it. It made perfect sense to me in this video.
@@АлтайскийКазак to be fair, you basically only learned to read a number off the chart. To use that number to actually do something useful is an entirely different matter.
Partially right - at one end of the chart you have a singularity where the universe breaks down. If your design ends up there it's a sign that it won't work.
@@АлтайскийКазакhigh level college professors are notorious for not being able to actually explain anything. You can tell they are smart, but they are also horrible at effective communication.
I'm also fairly certain that my textbook didn't actually have any information on how to use a smith chart and instead just gave us the formulas.
And even if it is explained, you better hope your compass and ruler skills are up to the task or you will follow the steps correctly but still end up a wrong answer because the charts introduce imprecision.
I want to find the history of Phillip Smith and there isn’t much on yt. Past this chart
I had an excellent professor for emag. Zach's explanation is as good as you will ever get. I had long since forgotten why the heck I even used the Smith chart, but this was an AWESOME refresher and now I'll never forget it!
I’m an echocardiographer. Believe it or not we have to take physics classes and pass a physics registry/licensing board before we can even sit for our echo registry. We learned a lot about wave physics, fluid dynamics, types of doppler, impedance, attenuation, etc etc. It’s really amazing how much of that stuff is relevant to this. So much of what we learned about sound waves applies to light just the same. Really cool.
Yep - because waves are waves. It's only the frequency that assigns what we call the signal type.
“What we have called matter is energy, whose vibration has been so lowered as to be perceptible to the senses. There is no matter.” - Einstein
I began to took Physics in 12th Grade, I then wished that it had started much earlier because the value of the math became very obvious.
I'm a EE, and while working for an earthquake simulation lab I learned that the same equation I use to calculate reflections in a coaxial connection is used by civil engineers to calculate the energy reflected by a building's foundation during an earthquake.
Yes. Look into the difference between microwave and radio transmissions.
As a mainly self-taught AV technician for many years, not having been to college or university to study this line of work, this is a fantastic video to explain impedance matching! Thank you :)
@jordanrodrigues1279 I've been following the audio world/mindset/craziness for several years and I cannot believe the level of misunderstanding, myths, lies and underhanded marketing out there about speakers, cables, amplifiers and other "snake oil". I wish I was smart enough to test, document and present 100% truth in data to put an end to all of it. I really want a recording oscope and/or strip recorder to help me layout side by side proof of the nonsense myths and Golden Ear hype about audio products. Surely, you have met some folks like I have. Oh! The funniest one to me is the people who are worried about "skin effect" in speaker cables - hahaha! All the best, Kevin
Per Wiki, This amazing chart was independently proposed by Tōsaku Mizuhashi (水橋東作) in 1937,and by Amiel R. Volpert (Амиэ́ль Р. Во́льперт) and Phillip H. Smith in 1939. I liked the charts published by Cincinnati Electronics. They were already pre-normalized to 50 ohms.
Thanks!
When the prof showed this chart in the transmission line class, he made some mention about how this was a circle of summoning great power. No joke, a classmate just stood up and walked off class making the sign of the cross. it was definitely one of the moments that happened during my EE grad
certainly one of the moments ever
Tesla was right apparently.
What a moron, these natural patterns in electrical current and other places in nature literally represent God, it's the face of creation itself. Buddy needs to study the Masonic church and their symbolisms like triangles, eyes and other strange symmetry that does NOT occur in nature. Someone like that would funnily enough walk right into a Devils trap.
Good for him. If you think these frequencies don't have the capability to bring forth energies from other realms overlapping this one, you are sadly mistaken.
@@theurbanthirdhomestead Oh you're talking about CERN, but CERN has to do with particle physics. It's who uses it and how. Electricity and currents are just a tool. Like when you give a gun to a satanist he will shoot up a school, but give that same gun to a hunter and he will provide you with food.
EE here. This charts seems fairly intuitive and useful within its field. The worst thing i dealt with was 3-phase transmission analysis. I literally had to buy a new calculator for my final because my options were to either get a calculator capable of complex inverse hyperbolic trig functions or decompose it, run the analysis separately for the inverse hyperbolic trig, then recompose it at the end. The homework and exams were often just 1 or 2 questions and would take 3 or 4 pages of diagrams, derivations, and calculations to complete with no general formulas, rather processes to follow.
I'm so glad the real industry uses steady state analysis everywhere outside dynamic modeling, because its even mechanically a thousand times easier.
This is where I am now. I'm in Electronics Engineering Tech, but a whole lot of Electrical Engineering curriculum crosses over to our own curriculum (For obvious reasons. We're doing a lot of the same things Electrical Engineers do, just on a much smaller scale.) I never thought I would end up doing math that took multiple pages of work to solve, but here we are.
There is a silver lining though, when my wife looks at some of the problems I have to solve for homework and proclaims "That looks like Greek to me!" I get to respond "That's because it is!" and it makes everything worthwhile.
Edit: I forgot to add that another positive is the fact that my shiny new calculator comes with python pre-loaded, so it's even more fun to play with than a normal scientific calculator.
Good memories.
But we were expected to program our hyperbolic functions ourselves. In FORTRAN.
I laughed out loud and shuttered at the same time remembering the one question final that took three or four pages and the entire hour, all it took was just one miss placed negative sign to screw up the whole thing. Oh, and no credit for the work only credit for the final answer. Good times.
@@DSquared1969 Engineers are such geeks.
@@jwrosenbury especially Electrical Engineers
I'm an amateur radio operator, and minimising reflections is important not only to improve efficiency, but also because reflections will fry thr RF amplifier on the radio at large enough ratios. We simplify this chart into a Standing Wave Ratio (SWR), and for most applications anything below 2.5:1 is good, though you can get away with 3:1 for lower power.
I’m not an engineer and these concepts never occurred to me before but they’re so interesting. Not sure why TH-cam recommended this to me but it’s honestly really cool to learn random new stuff. I never thought about electrical or sound waves and signals as having length that needed to be considered when designing electrical components
it's the same with light, think about the change of medium when it goes into water, some gets reflected, some pass and it is distorted, angles also affect in junctions, like when you dive into water, the wrong angle and you stop, in the case of electrical junctions it can make it heat up. BTW (about interesting things), if you want something extra interesting, look up superconductors and quantum lock, I find it fascinating.
I did RF double stub matching - long ago - but I couldn't do it now.
Then I found out that a hydraulic pump driving a pipe uses the same Smith chart
to do double stub matching for the sound waves.
We, who see the same videos recommended, are somewhat alike. :)
The real question here is... How did they even come up with this chart? Just by looking at it you already wonder how the hell do you place such values. Amazing stuff
It's basically like the complex version of the unit circle, resistance is the component on the real /horizontal axis, where reactance is the imaginary/ horizontal component. Together the restance and reactance make the complex impedance. Since the imaginary parts of impedance (capacitance and inductance ) are frequency dependent and inversely related to one another as such, this nice and clean for one particular frequency, but gets more tricky when dealing with multiple frequencies.
it has a correlation with polar coordinates, but I would love to take an active class to know it. For reference, an active class is one where the teacher doesn't teach you directly, they are there to guide you, not to give you information, so, for example, they give you a problem, and some formulas that you have to use, the problem is designed in a way so you end up rediscovering the target formulas instead of the teacher giving them to you, you learnt the process that it took to get there, in other words, you end up learning how the hell did they came up with those formulas. Those classes are hard to create, but so fun to take.
Agreed with both. Still, I would love seeing this chart being made from scratch, defining its scale, the relationship between the variables, etc...
Bell Labs came up with this in the 30s. There are only two equations, one for the constant imaginary and the other for the constant real circles. The real wild thing is what people plot on top of the smith cart, noise, efficiency, stability, output power, etc. based on a given range of impedances available at one port
It was a guy named Smith
I am a Ph.D. student in computer science, and this just brought back waves of trauma as an engineering major. Congratulations on teaching such a tough idea this simply. Would love to see more complex analysis based visualisations, which is the basis of Smiths chart.
I know EXACTLY what you mean, I got major in electronics and computer science myself. The fact people teaching that stuff at my university were probably the strictest of the strict there didnt help either : ^)
it's not a tough idea though!
is that why you chose comp sci for grad school? 😋🫣
jk.i was a chem eng student and my EE class wasn't easy when I took it but made sense when I reviewed it some years later to soothe my wounded ego. I really psyched myself out over it all at the time 😑
✌🏻
@john-ic5pz The idea is extremely simple, but taught to a 19 yr old without background in complex analysis, out of a slide and giving them the toughest questions to solve within a time limit is criminal.
I work on probabilistic robotics, so hell no 😁😆.
Don't forget that Z is a function of F. So you have to make sure your evaluation is done for the particular frequency. If (like with a ham radio) you're going to be using frequencies within a certain range, or perhaps two bands utilizing the same antenna (like 1, 2, and 4 meter bands, harmonics of each other), you need to have some sort of impedance matching circuit to be able to load the antenna/transmission line appropriately to your chosen center frequency.
When you take a class, then often use that knowledge in your career for many years, it gets to be very familiar. If you never use it, you'll forget most of it.
For instance, I don't remember that a transmission line typically has much resistance. What I seem to remember is that the 50 ohms is mostly capacitance, in magnitude dependent on frequency.
What I do remember is that signals don't flow thru a cable at the speed of light; only about 1/3 that.
Also, "ee-ee's" don't call themselves "ee-ee's". We are "double E's".
Brother I am a software developer and I know mostly nothing about electrical circuits other than the basics and you made this beautifully simple. Good job and keep it up.
Beautifully done, thanks. I'm a retired EE and this brought back an old memory from 45 yrs ago. When I was a young co-op student, the engineer I was assigned to gave me the job of determining the load resistance needed for some digital TTL transmission lines. This was a great learning experience for me, I had no idea until I watched the results on an o-scope. He could likely have simply told me what load to use but instead told me how to figure it out, a great mentor.
Learning the Smith chart just blew me away. There seemed something profound about being able to plot infinity on a piece of paper.
welcome to "higher" learning...there a vid about graphing e^pi x i , and other "imaginary" numbers....very cool, and visuallizing a 4 dimensions
Real scary stuff here
@@RwP223hardly. If you want a walk on the wild side; go look up conformal compactifications lol
I was introduced to this in the navy durring Advanced Cal Training as a Metrology Technician and this one chart made all of the pieces fit together for me.
Hmmm, learning ancient maritime laws in present maritime war training. 🤔
@theurbanthirdhomestead6061 i was a nuclear engineer in the navy, whats your point?
@@JgHaverty I was just thinking how this world really is a spiritual battle, and the ancient evil maritime spirits are actually being brought back by the world and its wicked ways, wars, violence, hatred, etc...
@@theurbanthirdhomestead what does marlinspike have to do with any of what you just said?
I am from IIT and i my self never saw so simple explaination. It is like i just whole my semester in front of my eyes.
Trust me this guy is delivering gold !
I did Electrical Engineering and The Smith Chart was definitely not the scariest thing. The scariest thing would probably be Z-transforms, root locus analysis, stability criterion, PID tuning or secondary protection design.
omg control system :((((
I studied those subjects and they are way betond whatever the math you see in a normal engineering course. It's a big leap of math
@@jamesandrew7120 thank god I did CompE and the only thing here that I recognize is the Z-transform, and only as a brief acquaintance.
@@jamesandrew7120yeah it’s the few courses where engineering is actually difficult
Omg control theory was one of the most fun things in my program haha, guess I like the mathematics more
I was a teaching assistant of some EE undergrads and got to learn this stuff. In the beginning I refused myself to read this chart, but once I knew how to use it, I started persuading every student to use it whenever possible!
You explained SWR better than most Hams I've seen. The only thing that would make this better is to explain how the resonance or lack of resonance contributes to the imaginary/reactive component of an antenna's impedance. Amazing video. You are one of my favorite youtubers.
In less than 10 minutes I understood more about how the Smith Chart worked than ever I did sitting through a 1-hour lecture at University!
just read the textbook next time, and you'll understand it in less than 2 minutes
@@pyropulseIXXI exactly.. I wonder why people post such exaggerated copied comments
@@pyropulseIXXI HI, That is what I did after the lecture and then understood it. My point was a TH-cam video did a better job of explaining it in 10 minutes than a University professor did in a one-hour lecture.
btw. Thank you for your condescending advice on how I should fill any holes in my knowledge after a lecture - much appreciated!
@@pyropulseIXXI if people understtod the smith chart in less than 2 minutes, everyone would be an RF engineer.
@@pyropulseIXXI you'll definitely understand WHAT the Smith chart is in less than 2 minutes, but that doesn't mean you will fully grasp all its concepts. What OP means is that he gained a better understanding by spending less time watching youtube compared to an hour of college lectures, and most of the time, sadly, it's true
I finished my EE program this summer, but never got to learn how to use the Smith Chart, It was only glossed over during a lecture but thank you for this very clear explanation. I finally understand what it's all about! It really is much simpler than it looks!
navigating my way round the smithing chart was difficult in college as it was conceptually challenging, YT videos saved me big time for my HF/RF module. i learned that it wasn't required to flip the smithing chart to switch from lines of constant L to constant C, so grateful for this invention. could not do matched loads without it.
I sure wish we had had TH-cam videos when I was an undergraduate Electronic Engineering Technology student. Graduated in 1995...
this is also what happens when light travels between two media with different refractive index, and a very similar graph (the acceptance plot) is used to design antireflective coatings
Math is beautiful and I love seeing it represented with a visual representation like the Smith Chart.
Absolutely. Makes perfect sense. To different levels in different ways
That thing was painful. Never used it a single time... But I became a power engineer.
I graduated with my EE degree almost 10 years ago, and to this day the Smith chart is my go-to picture for scaring interns away from engineering. It's been very good for job security.
Am I mistaken or is this done to prevent interns who can’t make it in the long run from wasting thier/your time?
@@anonymousadam8950 Read Charles Darwin. Struggle for existence, intraspecies
competetion for resources
@@anonymousadam8950if they majored in engineering or physics and they’re in an engineering internship, it’s highly likely they could make it as an engineer. I think he uses it to scare interns away from RF engineering, specifically, as it cuts out a lot of the people who aren’t passionate or interested in the industry as much as they are looking for any job to make money
They're very easily scared then
@@rv706 oh I agree. I doubt it actually scares anyone away. The smith chart isn’t even a scary concept, and I’m not an EE but I’d be really surprised if a 3rd or 4th year EE major doesn’t know what this is. They should be quite comfortable with all related math and physics concepts at that point, even if they haven’t seen it explicitly before. Algebra and calculus in the complex (w/ imaginary numbers) domain is the bread and butter of EE math.
I think the original commenter’s “weed out” method is really out of touch, and more so some sort of delusional ego boost for them. The only rationalization I can think of would be if he’s actually talking about electrical engineering technician interns, as they would be 2 year degree seekers/graduates with far less experience and depth of knowledge on the theory behind EE. Then it would be borderline cruel.
Zach, you sound a lot like MajorPrep.
OG viewer
He's the same person
Surprisingly, they are the same thing
Sounds like AlphaPhoenix to me!
When I went to Electronics School we learned this as Standing Waves. We didn't use the chart, we learned how to measure and trim for it. It was a 2 year Electronics Technician course that paid me back in spades. Back in the mid to late 70's.
Smiths charts weren't the scariest, at least I understood the process and results. Laplace transforms though, now those were scary and I never really understood when we'd ever use them.
Of course I haven't needed to use either in ~40 years since. RF really is the dark arts of electronics.
Laplace transform is indispensable for control theory and system analysis - and (just like any other subject) not that hard to understand once you understand it. Yes, the recursion is intended.
I used to fear Laplace in Diff eq. But then in Circuits Analysis 2 I learn it was my best friend in RLC circuits. Trying to do any work on an RLC without LaPlace was just shooting yourself in the foot. It was many times more complicated and longer process. While using a laplace, adding all components then reversing the laplace is just a fraction of the process. With the table you can do practically most scenarios, otherwise a good calculator can help you with it (TI Inspire Cas ii) when programmed right or if you know the equation (integral) process.
To me was like fearing Polar equations in calc2, but in calc3 were the easiest way to solve certain equations. Although the point of engineering was never 'how to use tools' (that is something you have to develop on your own), it is When to use them. Thankfully as you said, IRL work is much detached from those processes.
(Granted, Statistics and probability is the most important course any engineer should take no matter how detached it is from the essensance of their concentration).
- Computer Engineer
laplace transforms are easy; I think people don't understand this stuff because they view math is a tool rather than the fundamental thing to all of existence
I double majored in math and physics; math people thought physics people were too gung ho and sloppy with math (which I agreed), but were too stuck in their generalizing ways and would be very shallow and general.
my entire purpose was to get a PhD in theoretical physics, combining the best aspects of math and physics into one
with laplace in control theory, divide output function over input, laplace transform, project result on unit circle in complex coordinates. your operating point lies outside unit circle -> unstable.. as far as i remember
@@pyropulseIXXI Hey can you tell us even more crap we never asked about you? Kthx
This brings back memories of my 45 years in aerospace engineering. I worked on radars and telemetry systems at the big aerospace companies in the LA area like Hughes & Raytheon. It was a lot of fun.
That's great 👍
Hi, a quick question from an undergrad student here. I'm studying a double in EE and Physics, do think my degrees are a good skillset if i'm looking at pursuing a career in aerospace?
Absolutly
As an RF engineer much of product tuning is this very thing (impedance matching). We used metal tabs on microstrip transmission lines, as well as dielectric & ferrite chips.
I loved Smith charts! They were the most intuitive, straightforward thing I learned in EE. Beautiful combination of real and imaginary numbers. Nothing scary at all about these...
Just had my exam on this subject and it was one of the most pleasant subjects to learn out of ee
I'm a radio technician and this here is the best explanation about swr I have ever seen
I work in sales, and I watched the whole thing. Holy s*** youre a great teacher. I know nothing about the EE field and this kept me engaged and I understood a lot of it by the end. Kudos friend
I knew zero about this before the video and now know a little more. Fascinating patterns in nature. Love it. Subscribed.
I learned to use a Smith Chart and circular Smith Chart calculator 57 years ago when vacuum tubes were still being used, and later worked with air traffic control radar systems in the early 1970s. Think of a klystron in a microwave oven that generates pulsating waves of electrons that get funneled down a wave guide and out into an enclosed oven cavity. The oven cavity is the terminating impedance of the wave guide, and when empty it has low resistive impedance. Low resistive impedance means a lot of energy would be reflected back into the wave guide, back toward the klystron. This reflected energy could overheat and damage the klystron, which is why they say, "don't operate the oven empty." When energy-absorbing items are placed into the oven cavity, the resistive impedance increases and less energy is reflected back, allowing the oven to do its job. The Smith Chart and calculator were likely invented and perfected to support the development of radar systems prior to and during WWII. The microwave oven is an offshoot of radar research and was invented by accident in 1947. In a radar system the energy from the hollow wave guide is blasted out against a reflective dish and out into the air. The energy-absorbing air acts as the resistive impedance to the energy-producing klystron.
Very nice how you described the Z of an empty oven as a termination to the transmission line. I thought it would appear as an open, high Z. When you put a metal object in the oven, does that increase or decrease the load Z? We know about the sparks and such and an even more likely situation that the magnetron could be damaged from reflected power. I have considered mounting a microwave oven magnetron at the focus of a parabolic dish and modulating the anode voltage for AM at 2.4 GHz. I have not done it yet but I still think about it sometimes. I have wondered how the magnetron would react into the dish and what load it would see if placed at the focus. I figured it might appear as an open or at least high Z. Might make for an interesting EME (moon bounce) project for amateur radio. Just curious.
As a lowly Ham operator I have often had questions about transmission line/antenna impedance matching and this video was so simply explained it quite figuratively blew me away.
I was a electrical engineering technology major rather than EE proper, and also took more of the digital route- so i hadn’t seen this chart before. Awesome video and makes me want to get back into books and study more analogue haha.
Having learned that at the age of 15/16 in engineering school, over 25 years later i still find the Smith Diagram an incredibly elegant and "simple" help for dealing with impedance matching. (Hope impedance matching is the correct term in english, as i didn't learn that stuff in english as it's not my native language)
And i have the utttmost respect for anyone like Phillip Smith who can come up with something ingenious like this diagram.
Took me a second to realize that you were not saying that you were in engineering school at an age less than 1.
@@annieZOK 😁😁😁
-> engineering schools here usually are from age 14 to 19 if you pass all exams.
-> 5 school years of 40 hours of school per week. (not counting homework and studying for exams)
9 of the 40 were practical work in workshops. So in my case: on a lathe, mill, learning to file precisely, soldiering, circuitboard etching...
And of the remaining 31 hours 80% were calculating things. (the 20% are languages, sports, ethics and a tiny portion of "law and citizenship and finances"
There is also the possiblity for "grown ups" to do engineering school as "evening school" after their workdays, but i am glad i did it right after mandatory school.
What country are you in? Your education system sounds like it takes good advantage of the energy and curiosity of youth, getting them involved in career/higher level courses earlier than they usually are here in the US. Our "high school" programs can vary widely from state to state, even district to district, some doing a good job at preparing students with essential skills to move on to college or a trade certification, others not even graduating students capable of essential communication or math skills. I keep hoping that the decision makers will look at what's working elsewhere.
@@erinmcdonald7781 Austria.
And we are the only ones to my knowledge with engineering schools like that.
Sorry in advance, this is going to be a long one, trying to explain how it works here:
We have something similar to elementary school from age 6-10 (4 schoolyears).
From age 10 to 14 there was, what would translate to "main school" and today is called "middle school". (4 years)
Mandatory education is 9 schoolyears.
So either one has to do 1 "polytechnikum", or go on to a "higher school" that takes longer anyways.
People who decide for only the 1 year only, after said year, then usually start an apprentice ship (at age 15) to learn crafts or trades.
These apprenticeships take place at companies who use such crafts/trades people and they train them in the practical work.
And for 2 months or so each year they attend craft/trade schools. (so they learn the theoretical needs for their craft)
The apprenticeships take between 3-4 years depending on the craft or trade they learn. (carpenter, mechanic, cook, hairdresser...)
After their final exam, they are considered "craftsperson" and can be employed as such.
If after their final exam they want to step up their game another stop, they can attend (on their own money this time) further courses and attend a more difficult exam which makes them "Meister" (master of their craft, not to confuse with the university study title Master which is used in it's english wording)
During an apprenticeship the apprentice gets an "apprentice compensation" (so the salary of an apprentice is a little lower than that of an approved craftsperson)
If one opts for higher education instead of an apprenticeship there are said "higher schools". And of those there are 2 types: 4 schoolyears ones and 5 school years ones.
The 4 year ones are called "allgemeinbildende höhere Schulen" would translate to "higher schools for general education". (they usually have a 3rd language, and arts etc.)
And the 5 year ones are "berufsbildende höhere Schulen" which translates to "higher schools for professions/crafts education"
And for a better understanding, these are the engineering schools. (they produce engineers so some of us call them engineering school)
Cause as a student of these you learn around 80% of what a university student in the same field learns, but you spread it out over 5 years and you get more practical training in the workshop. (and you start earlier in your life)
Both of these higher schools have final exams.
But the 5 year ones are a "bit" harder iif i may say so.
To get a little taste of the final exam of an engineering school at the turn of the millenium, mine consisted of:
5 hours of written german language exam
40 hours of project work exam (getting a task, then calculating, drawing, programming, making parts-lists... without talking to your classmates who are in the same room, and only using books and tools you brought in on the first day and no finished projects among them.)
-And lastely oral exams in 4 school subjects. My four subjects were -measuring technology, -information technology, -electronics and digital techology and -english.
These oral exams were in a way that you can pick between two topics in each subject. (out of all the stuff we learned in the 5 years prior), then get 10 minutes of preparing and then have to hold a presentation in front of a commision about the topic you picked. And of course answering possible questions of the commision.
And passing such final exams in either higher school means one is allowed to study at a university.
But with the engineering schools you also are trained in a profession and can start working for a company, or found your own.
Companies all over the world do hire such people. Former classmates of mine were working in Brazil and the UK from what i learned at my last class reunion 5 years ago)
Sometimes as middle ground (translater) between workers and uni engineers, but often also instead of uni engineers.
Btw.: those engineering schools have a long tradition here. The engineering school i attended had it's 100 year anniversary at it's current location 2 years ago.
Let us know which country you learned this at… I agree with @erinmcdonald, it’s great to start teaching young, energetic minds about the more complex concepts of the subjects they’ll take in university/college. Thanks.
2:20 This is probably the point where any non electrical engineering student stopped. "Why do you mean complex numbers? Why would you use a complex number in a circuit?" 😂😂😂
You nailed it at 2:20…to the second!
The usage of j as the imaginary number buts me
Wow, thank you for that! As a EE undergraduate and an amateur radio operator I’ve seen the problems of SWR and in feed lines to antennas, but never could visualize the reason why your can burn out a radio from that reflected energy.
Energy not delivered to the antenna is reflected back to your output transistors and fries them.
This was my favorite class in EE! Took it as a senior and got 99s and 100s on all the exams.
dang. my best is getting me 85-99.. any advice?
@@josho9910 my first few years of college were extremely challenging, so I went in with the mindset of, “I’m not going to fully understand everything, and will be taking home B’s,” which may have been more mentally healthy, but setting low expectations for myself just created a self-fulfilling prophecy. Go into classes and units with the mindset of, “I’m going to become an expert in this field. When this class is over, I’ll be able to explain what I learned to a fellow engineer, my parents, and a child.” That mindset will take you far.
@@trinity8675309beautiful reply. Love the 3 audiences to imagine giving an explanation. Only being able to explain to any strict subset of the 3 shows you lack understanding.
Good lord. At my uni the highest mark on our Telecoms class final was like 62%, and that was an open book exam. That was the hardest class I did at uni by far, and I'm convinced that it's all magic and that telecom engineers are wizards.
@@trinity8675309 I've been trying to fill that gap. just did 92% on exam 2 of precalc and Its mentally challenging trying to get that other 8%
First time I can see this chart explained so wonderfully clear. Good job !!
This is just a simple conformal mapping of impedance in terms of complex analysis! I loved this chart, it was easy to use for wave guides!
But did you get scared and have nightmares?
@@tranzco1173 On contrary it was like a wet dream 🤣🤣🤣🤣
Love it when simple math ideas have profound engineering impacts!
When I was a young tech, a great engineer that I worked for taught me about Smith charts. "Oh, I get it" seemed straightforward when he explained it. But in the intervening years I really had no use for them, really, and now I probably would be baffled again. At least now we have affordable instruments that can make it easy to plot one out.
This was better explained than most of the engineering courses I took in college
I literally have my examination on transmission lines tomorrow and the timing of this video could not have been better.
You're gonna get an F, because this was so terrifying you won't be able to sleep.
Excellent! I did an Electronic Engineering degree many years ago and never really understood what you have just explained in 9 minutes - thank you!
That went totally over my head but I was curious...at first... then I got excited especially when he started to explain how the cone thing works😊 Pretty interesting stuff
Very well explained. Love the layman's explanation at the start ❤
I can't tell you how many times I've seen this chart and wondered what is was used for. Wow, this was a great presentation. Thank you.
Honestly, it was really simple compared to other concepts I had to understand in my Electrical Engineering course, but it's scary at first glance
I was expecting some abstract physics thing about infinity that would cause existential dread... but the idea of being responsible for understanding and using this material in a real-world engineering context is incredibly intimidating haha. That said, this is extremely well explained and informative!
How was this chart invented in the first place?! That's amazing. How can someone be so genius to imagine and implement such a tool?
Thank you for this helpful video, I am a communication engineer and I think smith chart is misrepresented as being “scary” but in fact is simple and helpful tool that doesn’t require a lot to understand in my opinion
I remember struggling with the smith chart at first in college. I would have loved to have a video like this as an introduction - definitely would have saved me a few headaches.
I own a window cleaning business and this is completely irrelevant to me honestly, but fantastic video I feel like I fully understood everything
Thank you for the video, this brings back some good old college memories.
The only subject that I ever flunked "Transmission lines"
As a civil engineer this video was a nice challenge to follow along and recall the physics and mechanics that correlate. And Btw when you have highlighted in purple the Smith diagram it looked the same as Mohr circles that describe the envelope of a certain shape or material that can describe the maximum tension states in the basic stress planes.
Just learned about this in circuits 2! Power companies utilize a circuit with incredibly large capacitors in parallel to create a false j0, therefor no visible impedance (capacitors are measured in negative j values). This is not done with our homes because we do not typically have to many inductors in our houses, but factories use motors all the time! Motors can actually give the same effects as inductors since it utilizes electromagnets, which is what inductors literally are.
I'm an elevator mechanic that loves physics. I can see how this plays with variable frequency motor control drives, and have a deeper understanding of harmonic resonance thanks to your video.
Stubbing a transmission line is really cool, I'd love to see a video on it from you.
Thanks for the learning!!!
The scariest thing I learned in this video is that I'm an absolute ape and cannot comprehend how somebody came up with this.
Nope. It took multiple generations working on handed down knowledge, each adding something, to get here. Even Einstein was working off existing knowledge men before him noted down.
It's simply a graphical way to solve nonlinear equations in complex variables. How hard could it be? /s
Physicist here, learned something new about electrical engineering that was presented in a very clear and understandable way. Amazing work!
Very interesting, I remember learning Transmission Line Theory in some EE course in college, but I don’t remember learning this chart or how to match impedances
That comes in Microwave & RF design (Electronics & Communication domain).
I am so used to him making comedy sketches , that sometimes I get confused when he gives educational content in the same voice 🤣
Beautifully explained. I’m an MSEE trained in semiconductor design, but now running a software company. I’d lost touch with smith charts long back (right after my BSEE) due to my career path.
This set me straight, getting in touch with my fundamentals. Thank you! 🙏
I remember this. We had to se a very similar chart when adjusting poles for the radio antenna in the Marine Corps back in the day. The radio ops would just memorize the frequency and poles, then when something didn't work right they called me and I had to use this chart thing. I used to try and explain it but everyone just stared at me. In the end I told them it was just basic magic, and they rather believe that then the actual science that went into it.
0621s unite
Thank you, the whole impedance matching thing makes more sense now.
It's more accurate but less intuitive if you think about the stub as being a third, much shorter rope attached to the thin rope, that resonates just so and cancels out the reflected wave from the junction. From far away, though, the "one big rope" analogy is good enough.
Bravo! Probably one of the best and simplest articulation of a complicated phenomenon. 🙌"If you cannot explain something in simple terms, you don't understand it." - R. Feynman
I'm 14 and this is psychological horror.
People usually respond with fear or anger to the things they don't understand, it is only natural.
It's OK buddy, you have a lot to learn before this start making sense.
I'm 14 too and this is pretty easy to understand ngl.
Zach, an idea for the next video: why a complex, non-physical value is used to measure impedance. I think you already had one about Laplace transform.
FWIW, I've seen a slide rule for high-frequency EE. It was Japan-made, I believe. It also had a scale for impedance matching. I was 15 or so, the stuff flew way over my head! I only remembered the words, “impedance matching.”
I second that. I received my BSME in 1984, and to this day I still don't understand "imaginary" numbers. I mean, you can't see or touch them, so how can they "exist"?😢
@@markfreeland1027 Glad you have no issues imagining infinitely many rationals between 0 and 1, and _a larger_ infinity of reals between 0 and 1, _exactly as many_ reals in this “small” interval as there are reals between ±infinities, so it's not in facts “small:” it's as large or small as those between 0 and 10¹², or ‒0.0001 and ‒0.001, or ‒10¹⁰⁰ and 10¹⁰⁰. Good for you that you're getting mental hiccups only from imaginary numbers! :))
Seriously, my point was very, very different. When we talk about rationals, reals, complexes we just mean a set of objects satisfying axioms that define an object called the _field._ The main idea is that we can add, subtract, multiply and divide them, and every time get another object (a number) from the same field. Also, there are special numbers 0, such that 0+a=a+0=a and 1, such that 1×a=a×1=a. Division by 0 is usually excepted, although complex numbers may be augmented unambiguously by a _single_ infinity, a limit of a circle of infinite radius from the origin of the complex plane. Reals cannot: is 1/0 +infinity or -infinity? oops. Positive reals can, tho, and this is also useful in other areas. In complexes, we get poles when “dividing by zero,” Consider the transfer function of a filter: it's a ratio of 2 complex-values polynomials, where roots of the numerator are zeroes, and roots of the denominator are poles. These zeros and poles characterise the filter completely. Fields are formed not only by numbers: there are also vector fields, also very useful in physics: say the field of gravity, characterized by the vector, a force acting on a small test particle, everywhere in space. Fields are formed my square matrices of given size, and in quantum mechanics, matrices with complex elements are very useful. Complex numbers are extremely useful in physics, not speaking of maths itself. There are 4 types of numbers that form a complete algebras: reals, complexes, consisting of 2 reals (a+bi), quaternions (4 reals, a+bi+cj+dk, where are 3 “imaginary” units i,j and k), and octonions, of 8 reals each. Quaternions are very useful in computing spatial relations and projections to the plane of view, and chances are, if you play a first-person shooter game, it's maths is built on quaternions. Octonions find their use in the description of the strong force, which holds protons and neutrons, particles of 3 quarks each, together. This is a very complex quantum theory.
Complex numbers are just everywhere! Watch 3blue1brown videos, and you'll grok them. The beauty of them is that they can be looked at in two ways. You can define a complex number by a pair of reals as (a+bi), a point (a, b) on the complex plane. You can multiply them as normal polynomials: (a+bi)(c+di) = ac + bci + adi + bci². i²=-1 by definition, so the result is =(ac-bc)+(bc+ad)i, also a complex. But in EE, another representation is more useful. Since a complex is a point in complex plane, with perpendicular axes (horizontal axis is traditionally taken to be real), the line from the origin to the point representing the number defines a rectangle, splitting it into two equal right triangles. By Pythagoras, the length, or _absolute value,_ or magnitude of a complex number z, is obtained from z²=a²+b². So you get a circle with the radius z, where all complexes of the same magnitude |z| lie. To fix a specific one, you need also the second number. Most useful one is the angle φ, counted counterclockwise from the positive direction of the real axis (usually, horizontal, left of origin): tanφ=b/a. This angle fixes one number on the circle _down to an arbitrary multiplier_ k×2π, k integer, i.e. ±k full circles around don't change anything. This is called the _argument_ in maths, but in EE, think of it as the _phase,_ and the magnitude as the _amplitude_ of a sine wave. This is the most useful representation in EE: phase is also defined down to k×2π. Instead of writing z=A×(cos(ωt+φ₀)+i sin(ωt+φ₀)), where A is the amplitude A=|z|, which is a mouthful, use Euler identity and write z=A×exp(-i(ωt+φ₀)). Multiplication and division of exponents is much easier than that of polynomials!
The usefulness of complex numbers comes from the Laplace transform. You take a _real-valued_ signal x(t), and the transform, which is one-to-one, spits out a complex-valued function z(s). What is s? it's a complex _non-physical_ number, just a parameter to find a point in the transformed space.The EE maths magic that happens is, inductances and capacitances are transformed into simple linear components that can be multiplied and divided (resistances remain real). Your AC signal is processed by a circuit of L and C that have a complicated behavior in time domain. But in the transformed space, they are simple polynomial ratios, easy to manipulate! After you did all the simple maths, you may do the reverse transform and get the output signal. You also very easily compute the group delay, spectrum, frequency-dependent phase shift, and so on. It's hardly computable in sinφ+icosφ form: you'll run into stuff like sin(arcsin φ+arcsin ψ), which is nigh impossible to work with. So the essence of the trick is (a) use one complex number instead of two reals, namely amplitude and phase, and (b) use a special transformation into _purely mathematical,_ non-physical space where analysing the signal w.r.t. capacitances and inductances is much easier.
My *main point* is not that the s in the Laplace domain (usually called s-domain) is complex. It's fine, you use normal algebra to work with these complex number. The main point is that anythings we measure: time, distance, velocity, force, voltage, current, just anything at all is real-valued. Your voltmeter reads 5.5V. You never read 5.5+2.5i volts, that would be nonsense! Yes, the wavefunction Ψ of quantum mechanics is complex. But, first, we don't _observe_ it, and second, its phase has no consequences at all, only its squared magnitude, which makes physical sense, has; the phase cannot be discovered in any real-world experiment. It's a maths crutch for computation, which doesn't correspond to anything in reality. So nothing-really nothing at all in the real world-is complex-valued! This was the essense of my request to Zach. Complex numbers occur only in applied maths devices invented to make our computations easier. But when we are back to the physical, real reality, everything is real-valued. This fact is at least notable to me, if not awesome. Physics is written in real numbers, real-valued vectors, real-valued tensors and other real-valued stuff. We use a lot of other, mathey objects-in physics, mainly complex numbers-that make computation easy, but always start and end with reals only. This is the gist. We use complex numbers so much and so naturally that we forget that they never arise from physical measurements in the first place. This distinction must be made very clear in communicating science.
A deeper mystery is that, weirdly, we can use real number measurements to build theories that predict other real-valued measurements-i.e., describe the world in real numbers. Is it a property of (a) real world, (b) real numbers of (c) our mind inventing theories? “The Universe is complex just enough to produce physicists, yet simple just enough so the physicists can understand it.” Isn't that… uncanny? But that's a whole different can of worms.
The chart looks like a tunnel turning to the right
0:48 of course it's RF Voodoo
0:05 ooh what’s that?
I think I discovered the catalyst for learning and understanding. It’s passion and how much you are interested in a topic. Making you wanting to understand a topic very badly and passionately. If this isn’t present, forget about teaching anyone something they don’t care about. They will most likely fail. Passion and interest allows a student to listen deeply to understanding instead listening to hear. It also overpowers the fear of failure. If you care deeply about a subject, failure won’t discourage but will be used as fuel to get to an answer or understanding. I think this is what formal education systems have disconnected with the student to learning/knowledge paradigm. A teacher that tries to instill fear and negative reinforcement instead of instilling passion, wonder, curiosity in their student will almost always fail in teaching. There’s is a high correlation between passion and success or understanding. I remember learning high school physics and calculus because and being bored so I retained nothing and was a average student. I didn’t pick that that is what I wanted to learn with passion. Now after all my schooling, I find myself researching and learning about things I’m more passionate and curious about. The result is that I am understanding them with ease. History, Science, technology etc. have become so interesting to me as an adult such that now they are much easier to grasp and comprehend. The missing variable was passion and desire. Previously I didn’t understand or care to understand because they said I “MUST” learn but now I understand and learn so easily because I “WANT” to learn. Took me way to long to understand this concept.
Despite multiple semesters covering all of the complex number math involved, nothing I had in college explained the PURPOSE of the math and the intuitive implications resulting from the math. FANTASTIC animation and explanation.
Subscribed! Great video. Really appreciate the clear and simple way you explain the real and imaginary parts of the wave properties and the use of symbol j instead of i.
Lots of physics videos and lessons miss properly describing these key elements and leave learners in a difficult position. Great job.
0:13 My dubstep mind got triggered
Pdf file?
i’m sorry but what’s scary about this?
A butterfly flaps it's wings, and the universe breaks down from computational complexity. This universe is inside the engineer's head as he tries to understand the Fourier transformations need to calculate it's echoes.
I imagine he means “scary” as in intimidating to a student approaching the material for the first time. I think he does college tutoring/instructing professionally.
Content, organization, delivery, concision, animation...great job all around, Zach Star!