Corrections and FAQ in this comment! Check out the other channel for follow up videos, and video Q&A that I'll be posting in a few weeks with questions from here and from Patreon! www.youtube.com/@AlphaPhoenix2 Check out the Patron page if you want to support the channel, get early access to videos, and join us on Discord! www.patreon.com/AlphaPhoenix Thanks to @ElectroBOOM for giving me a sanity check on this data a few months ago! (I hope you like the final video) FAQ: 0) Questions about the experimental setup (including the effect of the probes on the circuit while I was measuring) are here! th-cam.com/video/sty0Y1qmgEYc/w-d-xo.html If anybody wants to recreate this project, or turn it into an undergrad physics lab. hopefully there's plenty of info there! If I can remember how to use github I'll post some of my visualization code and leave a link on that video. 1) Lots of commenters have that I'm confusing voltage and current at times, but I tried to be very careful with my language. Current is the actual motion of the electrons, and in the graphic I showed with the blue dots moving around, I'm calculating that motion based on the voltage. it's basically the current that is NECESSARY to produce those voltage patterns. I also did a measurement where I measured the current directly by placing a very small resistor at the input lines and measuring the voltage drop across it over time, so I know my calculation lines up vaguely with that, but it WAS only a measurement at one point. If somebody wants to put a quarter ohm resistor every 4 feet along a wire and measure more voltages, I'd LOVE to see the data! I'll talk about the script a bit more in the Q&A video that hopefully will be out in a few weeks! 2) When you first flip the switch, the battery doesn't actually see a "dead short". The current out of the battery initially is limited by the line impedance, which depends on the properties and dimensions of the cable. In this case, it's the same current you'd get by bridging the switch with a 150 ohm resistor! 3) A lot of people have questioned the use of the words "communicate" and "sending information". I admit I anthropomorphize a bit too much in this video, but particles and groups of particles "communicating" and the rate at which "information" can move are very important hard physics terms that don't imply the particles are thinking. "Information" here consists of things like partical position, and they pass this information between each other using the electric field. 4) Water is a compressible fluid. if water wasn't a compressible fluid than pressure wouldn't work and water wouldn't be able to flow around corners in pipes. The way I'm using it it's actually EXTREMELY compressible (in the lateral) direction because it's allowed to expand upwards without getting significantly denser. Electrons in a wire are orders of magnitude less compressible than water, but it's still worthwhile to think of them bunching up! 5) ...........keep the comments coming! i spent like 4 hours reading comments yesterday lol
I have a question, in your exemple with the open circuit we see the fact that the electron are closer in one wire. what happen when you stop the batterie ? (open the interuptor in your case) does the potential rest in the wire ? making it a small capacitor ?
@@user-zp5xt8em6lI actually emailed some early data from this experiment to Medhi a few months ago and he said it was cool 😊. I’m not trying to “prove” or “discover”, anything here, just demonstrate. Electricity is very well understood by humans, it’s just hard to explain.
@@user-zp5xt8em6lthat Veritasium video is pretty misleading. There would be some detectable trace effects due to the fields being in proximity but the full voltage only arrives later as you would intuitively expect.
I have a PhD in physics. That graph is easily the most instructive, intuitive thing I've ever seen about electricity and it's relationship to the wave properties of the electric field. Absolutely incredible experimental design and presentation.
Or, elementary psychology, you've been away from it long enough and not thought about it much in that time, bits fell off the cart. But since you previously learned it, this played easy primer to relearn. The power was inside you the whole time. *rainbow graphic
I love how the waves behave just like we expect them to -- with an impedance mismatch at the split, causing a mild reflection, and an expected difference in how the waves are reflected from the ends because of the difference in boundary conditions.
Excellent video, those data-driven animations are extremely clarifying. I'd never seen someone show a circuit settle into a steady state like this, thanks for putting in the effort.
@@StreuB1 so there will be a moment when the interactions will reach smallest possible energy transacttions between electrons given from quantum mechanics, but in these "large" systems it is afaik effectively infinite, but mathematically you can say it is definitely not
I am PhD Biomedical Engineer (hons electronic) and also MD (medical doctor). Congrats on excellent video. The same thing (wave reflection) happens in your body every time your heart beats. The outgoing wave in the large arteries reflects off the capillary bed and you get amplification of the pressure (equivalent to voltage) on the leading edge of the (systolic) pressure pulse. Not only that but as you age the blood vessels get stiffer (lower capacitance) and the distal impedance increases, further increasing systolic pressure. Of course you also get a multitude of reflections at every branch. Congratulations, if you understood what I just said you understand more about this than almost all doctors. PS. I have the exact same oscilloscope next to my monitor right now!
26:17 Not an MD. (Lay person). Visualize the effect of the electricity that is generated by the blood flow coursing through the circulatory system, how it is affected by each branch, affected by the increasing resistance as we age and the decreasing potential for optimal energy caused by stress. Visualize now how relaxation enhances potential by resolving some resistance increasing potential energy flow increasing capacity to more efficiently nourish cells of the organism increasing potential for enhanced health and wellbeing. Not looking for miracles here. Just my way of thanking you for your very articulate response to an excellent video.
This is a fantastic endorsement. I recently purchased a VNA, and learning to use it helped me understand impedance and transmission so much more than anything I learned in school or from reading. This demonstration managed to be every bit as effective, which is amazing that it could be done with just a very basic scope and stuff from the hardware store. Bravo!
Here is another way to think of this circuit. The open end twisted pair are a capacitor and and inductor. The normal charging constants for a cap apply. The shorted end is more of a pure inductor, again the normal constants apply.
That bar graph animation was one of the single best scientific visualizations I’ve ever seen, all the more compelling because it’s empirical, not simply modeled. Fantastic.
Just outstanding! Did Hon Physics to 18, and Engineering at Uni. Not once did I ever have someone so good, give such a comprehensive journey of "investigation " of all aspects of Ohm's Law with such compelling evidence of its disection! THIS is truly science explained, evidence based, and married to the theory and maths! The depth of knowledge required to be able to deliver this video is mind boggling! Modeling - hmm? Too many ways for it to go wrong, short cuts, assumptions......... Give me videos like this EVERY time! You don't get understanding like this from Modeling!😂
“In this video we’re _actually_ going to be able to record this circuit fast enough to differentiate between these four options.” What a Time to be alive!
When you said "and then I spent hours stripping wire at hundreds of locations to attach the probe clips" I rolled my eyes and thought whyy?!. But your determination to follow through is what makes this so special! Brilliant combination of experimentation, video, narration, and the data-driven animations... really impressive.
Fun fact to this video: Since the waves reflect once there is a change in the wire, e.g. an "unexpected" open end because the cable was damaged somewhere, the time between connecting the battery and the the arrival of the reflected wave can be used to measure how far away the fault in the wire is (its called reflectrometry). This is extremly useful when diagnosing where cables buried in the earth are damage so that you can dig up exactly the damaged section instead of having to dig up kilometers of wires until you find the faulty section.
At the airport I work at we recently had an underground wire break. The local electrical repair company came out to locate the break. They used a trailer that utilizes the principle you described. We call it the ‘Thumper’ as you can feel it in your feet when it sends a high voltage spike into the ground to the break.
@@RovDisco Thumpers like that are very primitive compared with time domain reflectometry gear. Modern form factor is a single-unit handheld (e.g. ONX-580) that can tell you exactly how far away your different faults are on the line. You'll get a different signal back for an open branch line vs. a short vs. something else...no need to even put anything at the far end of the line, although you can if you want to confirm a certain pair of wires really does take the path you think it does.
@@TwoTreesStudiotheir primitive reading is more than necessary for their purposes I am sure. They need to access a fairly large section to make repairs.
I’ve been trying to do the math to make something like a streak camera using oodles of repeated scope traces but finding LEDs with nanosecond ramp times is challenging xD
actually i was wondering when i saw the video title, how a "camera" of any sorts could "see" electrons in a wire. But he found the solution: multiple repetitions of the experiment, with oscilloscope probes at varying locations. Great.
After teaching basic electricity for 35 years or more this is the best explanation and visualization that I have seen regarding current and current flow and how the wire bunches up its electrons and releases them quickly or slowly and remember 6.25 million million million electrons flowing through a wire in one second equals 1 A so electricity is it all that magic you can actually see it and measure it
@@hydropage2855 most of it I already knew, but not from a single source, more the total of the education and experience I have. I did not realize the potential wave reflected multiple times across a DC circuit, though, I figured that only happened once, so that was cool to see.
@@daniellewis3330 I actually feel like it would’ve made more initial sense to me that it would happen many times, since pretty much everything in the world boils down to oscillations in one way or another, mathematically I’d assume it would “take forever” for this to settle down
IMO this is hands-down one of the best physics channels on TH-cam. Your ability to turn highly abstract and complex concepts (like the "speed of movement" which is a video I'll never forget because it blew my mind) into real-life experiments using actual measuring equipment is just amazing.
Your vids have already changed my understanding of electronic fundamentals, but this visualisation in particular absolutely took it to the next level. Thanks.
I've been utilizing "electricity moves like water" as a basis for troubleshooting and planning for decades, this is be best description, example and proof of this thought process I have ever experienced. Well done. Subscribed.
It's so awesome how you genuinely dig all of this -- you could have talked about it for hours! People with your enthusiasm make the best teachers! THANKS!
As an RF Engineer, the stuff you're talking about is my daily bread an butter. Still, I've never seen such a good visualization of electromagnetic waves, let alone based on actual measurement. Really cool and educating, even for professionals!
I'm also and engineer for a prominent company that designs/produces RF power supplies for plasma sputtering, semiconductor etching, metrology, etc. However, I design and write regression tests for our firmware. Specifically, I test the product that does dynamic impedance matching between power supply output and plasma load. Who do you work for? I wonder if we work for the same company ;) Reflections are a big part of our zeitgeist, and I agree that this video does an excellent job visually representing what reflections are and how they work.
@brentsmith7013 what I found interesting when first learning about RF, is how much more consequential everything in the circuit is. Like an axial resistor isn't just a resistance value. The leads and film material also act as little inductors and a capacitor in the circuit (to your point). I have a ton of respect for RF engies, because they are doing calculus vs me doing basic algebra.
Hobbiest RF guy here. I'll be using this video to talk about wave propagation in a transmission system, why we open/short/load a DUT, and more when I teach potential licensees...
I've seen the "ringing"/"bouncing" oscillation effect on an oscilloscope when connecting wires before but to see it graphed out spatially like that is incredible
I didn’t REALLY understand it until I could see it spatially. This is one of those cases where figuring out how to make a visualization ends up teaching me The impedance-matched version is WILD th-cam.com/video/RkAF3X6cJa4/w-d-xo.html
This may be the best vid of this sort I have ever seen. The beauty of not only the knowledge it discovers, but also how it was discovered and the joy of the experimenter literally have brought me to tears. I simply cant express how beautiful this is to me at each level and in the aggregate.
I've worked with electricity my entire adult life, and I learned more about the theory behind it (as opposed to the practical application I use daily) from this video than any of the class I took. The visualization of the current signals propagating through the two circuits blew my mind
I have a bachelors in Electrical Engineering and have worked in the profession for 34 years (retired). I have never seen electricity explained this intuitively in college or at my job. This was awesome. The similarities between fluid and electricity behavior are so useful to help understand electricity. It's a very tough thing to grasp due to how fast things happen on an atomic level. You figured out a creative way to capture it.
Yeah, I always pictured the initial wave explaining switch voltage spikes, but I always assumed it would dampen much faster than that. Seeing the electron loading bounce back and fourth almost 4 times before being dampened to equilibrium with the motive force was impressive.
My understanding is the electrons do not move , the electric field moves out side finds the electron at end of wire or switch junction whatever , They all teachers say electrons move yes but not in the way we think about movement in that way they don't
As a physics educator at a university, I love this video for so many reasons. First and foremost, this was amazing science done right. You presented a problem, made a set of competing predictions, established what data you were going to collect and related your predictions to your data (you said what we expect to see in every different case), then you took a copious amount of data (p
My favorite part of this experiment is that it demonstrates that, yes, electricity is made of actual "stuff" while also demonstrating that the actual information which defines a circuit must somehow travel at some speed.
@@AlphaPhoenixChannel Is this research correct? Unlike a simple Y wire with closed and open ends, the developed circuit already becomes an “inductive” circuit, moreover, with a connected oscilloscope completing the circuit. верно ли это исследование? в отличии от просто Y провода с замкнутым и разомкнутым концами, развитая схема уже становится "индуктивной" схемой, более того с подключенным осциллографом замыкающим цепь.
@@gt_xpert I am very from an expert but my understanding leads me to believe that all circuits have some degree of inductance (because they all involve current flowing and therefore create magnetic fields). Furthermore, the question wasn't what happens in this exact set of of wires with this exact resistance and this exact inductance, it was: "how does information travel in a circuit" which is much more general and I believe very very very well shown here
This might be the best video I have seen on YT. I can see how much work you put into it. And seriously, thank you for doing it. I studied EE and I left school not truly understanding it: none of this was covered in school, at least not in a way that made electricity intuitive. Years later, I feel so much more informed about what I studied. Thank you for your dedication, curiosity and creativity.
Dude!!!!! THAT WAS AWESOME!!! When I saw that very first animation of the flow levels spiking and reflecting, starting at 10:23, along with the spot-on ethereal music.... THAT WAS MESMERIZING!!! I can FINALLY visualize how DC behaves in circuits... and I've been working with electricity for 50 years!
In this circuit, the twisted pair functions as both a resistor and capacitor. The initial inrush current is taken up by the capacitance. When it reaches steady state, only the resistance is applicable. You have essentially reinvented a time domain reflectometer (TDR). It uses the reflected pulse to determine the length of a wire. It can also determine the distance to a fault or splice (useful for locating a fault or determining that a signal cable has been tapped). The same principle works for fiber optics. For security purposes, an easily broken and nearly invisible unsheathed fiber is woven through a barrier. When the barrier is cut, the fiber is broken and the exact location of the break is determined by the TDR. Hint: Don't ever try to break into a Google data center.
That's exactly what they did when my glass fiber connection was broken. I didn't understand how the measurement tool worked. He explained it, but to me, it didn't make sense at the time. Thanks for this. With this video and your comment, "reflectometer" becomes as easy to understand as echolocation.
So the ringing after the inrush spike is because of the stray capacitance and inductance forming a tank circuit right? Resonance at the natural frequency
So if I understand correctly, the initial reflection at the fork is caused by resistance(impedance?) change of doubling the wire cross section? If the forking wires were smaller and summed to the cross section of the initial wires there would be no reflection at the fork?
Reinvented TDR? You can go back further and explain why turning on an amp (audio or radio) without the (speaker/antenna) connected can destroy the equipment instantly! (ok, in a few nanoseconds, when that voltage inrush spike comes back!)
I am an engineer (electronics) and I hated transmission lines. I got around that after someone told me to stop looking at the equations as an engineer and more like a mathematician.
If your school offers it and you're at all interested in this type of thing, I'd recommend taking High Frequency Systems. No doubt one of my favorite classes.
I’m a sparky and you’re exactly right! I wonder if an led would light for a nano second if forward biased on the open ended pair, due to the rolling voltage gradient?
That is an amazing, intricate, time consuming and number crunching experiment and you basically proved that electric waves behave the same as ultrasound and other waves. For over 15 minutes I was yelling at my screen "CAPACITANCE!" It's almost like you heard me...
This channel is like a saving grace to people who already know the math and feel the physics but don't quite get it. It feels so good to understand what you thought you knew.
Yes, it remembers me what I learned decades ago on microwave wave guides and printed circuits. But it was all maths and fields back then, and harmonic signals. I never figured what could happen to electrons in conductors, specially the pattern of "charged" wires in an open-circuit DC line.
What a cool visualization, huge props for tediously collecting all that data! Something about seeing the real data moving in waves like that is just _so awesome_!
there were multiple times I think i audibly gasped looking at graphs while working on this project. the first was the test animation for propagation, which was SO satisfying, but my favorite was actually the time I accidentally impedance matched the circuit on the table and finally understood - I'm disappointed I ended up relegating that bit to the second channel but I couldn't explain it without more math lol
Greatest video of this topic I've seen. It shows the field levels, the electron compression and movement, the waves, reflections, and steady-state result, all while remaining empirical! Seeing the slope of the graph in relation to the electron speed and density is awesome.
This video is so satisfying. It brings the hydraulic analogy to another level, and it looks like putting electricity under a microscope, figuratively and very much literally.
Holy cow! I have a masters degree in physics and this is one of the most intuitive and understandable explanation of electron flow I've ever come across. I'm amazed on how much information you could gain with this "basic" setup. I also love your systematic approach and the brakdown of the system. Very well done sir!
@@flowildfellow electronic engineer here - @longnose154’s model is perfectly accurate because electron movement and wave propagations are analogous models for each other - basically half of the point of this video is to explain this 🙂
THERE ARE NO ELECTRONS. CHARGE IS BOTH POSITIVE AND NEGATIVE. METALS HAVE FOUR FIELDS. +/- STRUCTURAL AND +/-FREE CHARGE. WHEN YOU CONNECT THE BATTERY THE INDUCTION FROM THE POLES ALTERS THE RATIO OF +/- STRUCTURAL CHARGE COMPENSATION AVAILABLE FOR EQUALIBRIUM CONDITION OF THE METAL AND THE PLATES OF THE BATTERY. ALL MATTER IS MANIFESTING FROM THE AETHER CONTINUOUSLY. NEGATIVE AND POSITIVE CHARGE FLOW FROM THEIR RESPECTIVE POLES OF THE BATTERY TO COMPENSATE THE INDUCTIVELY MANIFESTED ALTERATION OF +/- STRUCTUAL CHARGE CAPACITY IN THE METAL OF THE WIRE. AETHER/HEAT IS UNDIFFERENTIATED +/- CHARGE WHICH DISSIPATES LONGITUDINALLY NOT ELECTROMAGNETICALLY FROM THE WIRE. THERE IS NO MAGNETIC FIELD AROUND A ROUND WIRE, OTHERWISE THE WIRE WOULD BE ATTRACTED TO AN IRON SURFACE. THERE IS AN ANISOTROPIC PERMEABILITY TO MAGNETIC FLUX CONCENTRIC TO A ROUND WIRE OF THE CLOSED CIRCUIT. A FLAT CONDUCTING WIRE WILL ATTRACT IRON AS WILL TWO PARALLEL WIRES CONNECTED TO THE SAME BATTERY POLES AT THE SAME ENDS.
This is just incredible work on the split wires and then the tapping with all those measurements and the graphs. This is just unbelievable work. I did not think we would get that detailed of an answer and hadn't even made a guess. Just amazing work.
That graph at around the 12 minutes point is absolutely fantastic. It really shows how your models with water are a very good representation of how the electric will behave. Fantastic work thanks for making these videos.
Wow. Just wow. As an electronics engineer I can say that without the shadow of a doubt this is the most easy to understand, visually impressive video about electricity I’ve ever seen - and the insane amount of work that this must have required just drips out of every pore. And I have never actually thought about how the waves flow… this is insanely interesting! Thanks so much!
This was demonstrated in my high-school Vocational Tech Radio - TV Repair class using Tubes & dual trace oscilloscope. the effect described here has implications in pulse & wave shaping for mil-spec IC substitute and circuit cross-talk. I am solving an ELF (Extremely Low Frequency) innovation where this demonstration is one factor in the solution. PhDs can be a challenge for explanations. 😊
In the early '80s, I built a semiconductor company to manufacture semi and full custom analog and digital ICs. Our designs were in everything from toys to spacecraft. It must be so much easier/more-fun to learn now, than then. I'm obsolete as hell, but this was fun to watch.
@@RickMcCargar In university a professor explained the concept of "software defined radio" to us. We were used to calculating antennas and frequencies and at first thought he must be joking. Then showed us his gear: a room full of equipment worth hundreds of thousands. Today I have one in a drawer somewhere, worth 150 EUR and the size of a box of cigars. But to me, honestly, it still borders on black magic that this concept actually works.
I'm a technical trainer who was wondering why an open circuit in a car's network system caused a huge voltage spike on the oscilloscope. This video single handedly demonstrated and proved what was going on and why. This was exactly what I was looking for - thanks so much!
CANBUS is super interesting stuff, I've spent many months studying it. This video re enforced to me how electronic networking is just voltage pulses of "information" sent down the line and detected. It's the same concept with how the battery "figures out" how much current to send down the line as it is in actual networking systems. Voltage is sent down the line and feedback is sent back.
@@kc7affsame with a process called "TCP windowing" in networking. The TCP tries to find a confortable medium between super fast data stream and dropped packets. (Source networking engineer)
Mate; you have just cleared so very many mental blocks, not just regarding electronic influence propagation - the falorn intent of watching the video in the rirst place - but in a number of other significant respects also.... I have struggled with a number of mental processing issues for more than six decades and have the complicated history of my life to show for it. The inspirational manner in which you have thought through your question; have aquired so many and varied tools and apperatus whilst mastering thier use and application to a more than adequate degree of comprehension and competancy; translated all into a material construct, visible, influenceable, testable; presented with absolute clarity, confidence and humour ..... I felt pathways opening up. I do not know if it will last, but I will now see if I can remain, to what ever degree or extent, within this splace which occupies the other side of the divide. Really, thank you so very very much: And I now get the piece of the puzzel where the propagation of electronic influence fits to boot !! Really, thank you and congratulations on the outstanding quality of your project :)
This has blown my mind. You've taken a bunch of difficult electricity concepts (some of which have been argued about for years) and cleared them up using a brilliantly designed experiment and clever visualisation technique. Really well done!
The bouncing and ringing are due to capacitance and inductance effects of the imperfect conductors. The two combined give you reactance, you measured it beautifully. This is also why we use termination resistors in data lines like RS485 at dead ends in order to avoid bouncing waves of signal causing interference.
It's not that the conductors are imperfect, it's that they exist at all; even a superconductor inherently has inductance and capacitance with the world around it, and a sole superconductor not in a transmission line would still deal with the characteristic impedance of free space. He's replaced the characteristic impedance of free space with the characteristic impedance of the twisted pair, but the dynamics are due to electromagnetic interactions of the current wave with itself, not resistance or imperfections in the line. It is the impedance mismatch at the end that causes the reflection.
For me it's easier to understand the behaviour of the disconnected wire considering the twisted pair forms a big capacitor. Huge voltage at first, as the capacitor is not charged. As it charges, voltage drops closer to zero. And all the resistances, inductances and capacitances make up effectively a RLC oscillator.
@@MrMassmaker They are, we performed similar measurements at EE school to understand conductors better in real world applications. In my case it was a spool of wire that we characterized with a signal generator and an oscilloscope.
Awesome! As a 40+ year electronic technician I knew the answer, we just always accounted for this as an initial "spike" when energizing a circuit, sort of "filling the pipes" so to say. Your visuals really brought it home for this old "sparky".
Old Sparky, so when I was a kid way back, parent or grandparents would say, "Don't keep flipping the lights on and off, it uses more electricity!". Is that because the initial first few waves it does use more energy than needed before it settles in? Now once they told us this we did it many more times because that what kids do. But they were right!
I'm a mechanical tech and I understand the concept of inrush current. This video was really good. I also deal with high pressure fluid circuits with dead sections that start and stop and this will be in back pocket from this day forward.
@@TUTruth The initial few waves don't matter much for power consumption. The reason they told this, is because the filaments in incandescent light bulbs change their resistance with temperature. When they're cold, the resistance is low and a high current flows. Once they heat up the resistance rises and the current drops. When you kept flipping the lights on and off, the filament didn't stay hot, so more current could flow
@@TUTruthFlipping the switch on and off actually uses less electricity overall. Light bulbs use a lot of power when you first turn them on because the resistance is very low at room temperature, then the filament heats up to maybe 2700 kelvin (almost immediately), resistance goes way up with temperature, and current goes down. This is why you can't guess the watt rating of a light bulb by measuring the resistance with an ohmeter. Try it. Measure a 100W bulb. The resistance at room temperature will make you think the bulb will use 10x that amount of power, but this is only true for a fraction of a second. The real reason to not flick the lights on and off is that it damages the bulb. Any time you've seen a bulb burn out, it was when you tried turning it on. They very rarely burn out while they are already on. Also true for fluorescent lights. Striking the arc wears out the tube.
I admire your tenacity and determination in pursuing how to explain this problem to non radio engineers, well done. As a retired radio engineer, we think in terms of the characteristic impedance of a line, its terminating impedance, and consequent reflections. That makes it easy. By the way, regarding the short circuit on the water line, the only way to replicate that is to have a very wide hole at the end so that the water can flow out without any height (= voltage) restrictions. My apologies if you already mentioned that.
55 years ago, I was taught by Western Electric and Bell Telephone instructors how to trouble shoot telephone cable. Much of this was already known but not very well explained. This does help visualize the way it works.
This is the most interesting thing I have viewed in years. It is the sort of thing I "knew" but didn't really "know". One approach for the water analog is to open the slot horizontally instead of vertically. Now, I am going to go back and watch this, fully, again. Very interesting!!
I've been a PCB designer for 17 years, some of my best training was a hands on hydraulics class that I took at a tech college. It's surprising how well the analogy holds up. I'm just an electron plumber. I love your video and really wish I'd seen something like it my first try through college physics.
The great thing about this channel is that it's not about fancy production values. Your technical skills and enthusiasm carry it all by themselves. Thank you for the effort!
Wow, I have worked in the electronics field for over 40 years and never gave this a thought. Thanks for doing such a great job illustrating what happens. Loved it. This also helped me appreciate propogation delay in conductors/coax. Keep up the good work!
This is one of the coolest videos regarding electrical propagation I have ever seen. Congrats! Even though you are dealing with a DC circuit, while it stabilizes it is behaving like an AC circuit with the transient wave reflecting back. So cool.
I have a physics bachelor's and i think this video should be shown in the first year. It really helps build an intuitive understanding of several concepts that I always struggled with until now. THANK YOU SO MUCH! It also begs for follow-on experiments such as demonstrating wire configurations with high versus low capacitance. I love that electron gas pressure propagation is so visible and that electron drift velocity is definitely NOT the same! This is inspirational experimental physics at its best capable of inspiring young enquiring minds to think about the phenomena in our daily world that we usually take for granted. SUBSCRIBED! And why do I discover this great channel only now?! All the best, Rob in Switzerland
This is freaking great. The video itself does not show, but the amount of effort it must have taken to get all these measurememts.... great job, hope this gets some nice exposure, because this really clearly explains how electricity works.
I sadly don't have a timelapse of taking all the measurements multiple times, but here's a video with a lot more detail on the setup! th-cam.com/video/sty0Y1qmgEY/w-d-xo.html
Time to reach out to LeCroy and Keysight and get them to sponsor you with a many-channel scope 😂. But seriously, NI makes 12 and 24 channel “scope-DAQs”… 😊
Thank you for putting such a massive amount of work in collecting the data and turning them into those visual graphics! Makes it SO much easier to understand!
This is beyond incredible. The amount of time you spent on something so ubiquitous and distilled it down to such an easily digestible morsel of information is absolutely brilliant. The animations were so fascinating to see, and I had chosen B for my answer, and when you showed the water flowing in the channels I nearly second guessed myself lol. Incredible work man, I look forward to your videos!
I also guessed B, but C was what I was picturing as I did. I think the wording was a bit confusing, as I was hedging toward B because it's a more physical description, where C is more anthropomorphized.
My automotive electrical instructor I had in college described electromotive force / voltage as a push. Now, I have a clearer way to picture it, as well as an appreciation that he explained it so well.
This is why the TDR (Time Domain Reflectometer) is so cool. It displays the "echo" of the electric pulse bouncing off the break. And that's how we used it in the telephone industry to find the distance to a cable break (or see the "bump" of a wiring closet on the way to the actual cable end elsewhere farther down the "circuit")
It doesn't just work with electrical signals. It works with optical signals too, although for shorter runs (like in planes rather than between neighborhoods) a frequency domain reflectometer, which doesn't rely on a pulse, but a constantly changing frequency, provides the necessary resolution.
What do you mean with shorter runs? In optics typical OTDR can measure fibre cable break distances 100 km or more easily. The longer the cable, the more time you have "to measure" but the more sensitive detector is needed.
I remember the wave of understanding when I was a kid and the guy that came to fix the phone explained how he could measure the distance to the break in the line.
That's an awesome video. You basically made a wire-version of a slow-motion video of a lightning strike! In a lightning strike, you see lots of tendrils explore all possible paths towards the ground until one connects. Then, boom - all other paths disappear and the lightning bolt appears between the ground and the cloud.
I have worked with computer networks since 1994. Back then (1994), I used to *try* (badly) to explain why leaving the terminator off an coax Ethernet cable causes reflections and can be detected by observing an increased voltage. Now, almost 30 years later and after watching this video, I finally understand those reflections. You do awesome work Brian, keep it up and keep inspiring new mathematicians and engineers.
cheaperNet (UTP) and switches made EtherNet networks a lot less bizarre, a lot easier to diagnose, than coax cables with a PDP-11/23 at the centre of the tangle (experienced in the early 1980s). the NBN (VDSL, in this case, to the nearest optical POP) router connecting this home to the world has four 100-megabit UTP sockets on the LAN side, and WiFi, yet copying bulk files between nodes is much faster across two pieces of blue string than involving WiFi anywhere, as any competition for WiFi bandwidth rapidly bogs things down.
This has been an excellent series, I am an avionics technician, we have a lot of rules of thumb, do this don't do this, that keep our circuits working. But few can explain the underlying why's in a coherent way. For instance we terminate unused data busses with terminating resisters to stop "reflections", here I see exactly what it is that we are stopping, return waves that stomp all over our signal.
@@mrblank-zh1xy I did it by joining the Navy. I worked on the AWG-9 radar system for the F-14 from 2001 until it was decommissioned in 2006. I also cross-trained to the F/A-18's radar systems, the APG-65 and the APG-73. Free training, plus a GI bill on top of that. I also went to 2M school (miniature/microminiature electronics repair) to round it all out.
I don't think people realize exactly HOW much WORK you had to put in to come to the result being depicted in this video. Like, the amount of testing and changing... building those frames, twisting the wires, splicing, connecting the probes, getting the data, repeating it again and again to get many datasets, trying out different ways to animate the data, comparing the animations to determine which animation looks best, comparing the datasets to determine which dataset looks best when animated, recording all of the footage, editing the footage, building the liquid model, etc etc etc. I could go on and on! I'd imagine this whole thing took a good part of a month. Like.... if you were to do _only_ work on this project 24x7, it would've taken nearly 3 weeks of working 24x7 without eating or sleeping or doing anything else! Hats off man, hats off.
Nice demo. When I was teaching transmission line propagation, it was always quite hard for students to understand the principles of the TDR, because they were SO used to the ideas of DC circuits they were taught in EE101. The idea that applying a DC voltage at t=0 initiated a wave, was very different from their understanding of a static DC circuit, and transient voltages were only considered to be the result of L & C lumped circuit elements.
This animation, the setup, and the measurement must've taken a lot of time to get right. This level of patience is something I aspire to have after watching this incredibly enlightening video. You are my hero. Thank you, from the bottom of my heart! This video should be a must in all undergrad curriculums.
This is the most complete explanation of wave propagation and line impedance concepts I ever saw so far. The idea is sooo cool. And yeah, I feel the same way regarding availability of relatively cheap devices that allows for literally light speed measurements on a bench. What a time to be alive.
as I have just completed my high school and i watch many videos on youtube related to science, electricity, physics,etc. but only some of them are my favorite channels and one of them is yours. I find your videos answering many of my doubts related to electrodynamics and electrostatics, very informative with deep analysis experiments and not just talking upper upper like most youtuber do to make their videos understandable for more mass audience and ignoring the audience that wants more details. I hope you keep up with your experimental videos. 😊
An absolutely amazing video. It is one of the best experiments I've seen in years. I can't believe that you manage to film the behavior of electrons with such a simple, but so well-thought setup. Thank you very much!
I'm a commercial service electrician, and this video has cleared up some VERY perplexing issues that I've run into in the past that were causing some sensitive electronics to act up. At the time I was able to "fix" the issue with luck, and trial and error but now I have a pretty good idea of what was happening. You learn something new every day!
Fantastic video! I have a master's degree in EE and work as an RF/antenna engineer and this is probably the best demo I've seen of these EM concepts. Amazing job breaking it down in such a way that I think anyone could understand. There's definitely some really interesting and cool material in the transmission line and RF realm which builds fairly well off of this, I'd love to see your take on antennas (and selfishly think whatever demo you'd come up with would make it a LOT easier for me to explain my job to people lol).
Agreed! I felt pretty good figuring out which option was the right one but I can only attribute that to my knowledge gained from Amateur Radio and antenna propagation theory. I would be fascinated to see this on an antenna with RF signals but also to include actual electron flow as well. I've always thought of electron flow through wire as similar to water, but have always had a hard time equating that to RF in a wire. I would love to see it mapped out like this and the two compared. Totally geeking out right now.
I am an rf tech and I suspect that brief moment of current starting through the circuit on the open branch the energy radiates. Looks like a dipole antenna. I paused the video before finding out the solution. I have done this thought experiment with millions of miles of open pathway on a circuit. How in the heck does the circuit know it’s a dead end without violating Einstein’s theory that no disturbance can go faster than the speed of light? From another perspective, the time factor may help explain why energy has to radiate from an antenna in the first place.
@@artofplanets Because Einstein is NOT the END-ALL definitive source, or Law Maker. The Universe is. And Laws can change when the environs reach states we dont ever (or hardly ever) experience, percieve, or theorize about. And even then, we dont always predict events with 100% accuracy in these areas. Short answer: EINSTEIN was wrong, and he even admitted it, if you look hard enough youll find it out there. The SPEED of LIGHT is NOT-EQUIVALENT to the Universe's "Speed LIMIT". There is no TRUE "Limiter" of Speed Full-Stop. Theres only changes of existent forces due to the current 'moment' and its environment/medium/surrounds. And that leaves A LOT of variation, some of which we still cant actually test for.
I think this is happening in my ham radio antenna, we refer to things like "SWR" or standing wave ratio describing how "resonant" a given antenna is, and therefore how efficient. It looks like a standing wave "sloshing" like water in a beaker that waves back and forth until settling. Very thought provoking video!
1. I love that there are people who are highly intelligent, with complimentary complex and multifaceted skills. 2. I love that I am sometimes able to comprehend what they have to teach/share. 3. I love that these people, including the Americans, use the metric system. 4. Today my day has been full of love and, interestingly... its 100% electric ❤
This is hands-down the best science video I've seen on YT. I'm in awe about how much time you spent conceiving, building, testing, documenting, visualising and then creating this video!
I love that you build the analogous water circuits IRL and then explain their limitations. Exactly what I try to do for my electrical students. This demonstration is perfect for my avionics students when discussing aircraft radio transmission lines like coax cables between equipment. Thank for investing the time for all of us!!
This is pretty amazing. I am an RF Engineer, and I have never seen a better illustration of my work. This really does tie into transmission lines well....Very impressive.
I swear, i've seen the slow mo guys show up in so many channels besides theirs, and I'm greatful that they're willing to share their insanely expensive gear with other channels. Hell, idk if they rent it, but if they do, that's a great way to recoup the cost.
As an electrical engineer, I saw this in my suggested videos and was in my head critiquing YT's recommendation algorithm for giving me what I thought was such a low IQ video recommendation on basic Electrical concepts. It kept showing up on several occasions, and eventually my curiousity of why I was getting such a lame recommendation caused me to click to scrutinize what value this video offered that caused it to be perpetually in my recommendations. Was pleasantly surprised at the way such a simple experiment offered a wealth of intuitive insight into how physics and electricity works, specifically circuit network impulses. Got to say, I was entertained and delighted by the educational value. A+
Fantastic! I don't normally add a comment. Not in Years. But you have demonstrated electron flow in a way that anyone could understand. I hope you teach professionally. Thank you for your efforts.
At 20:38 (and in other places) you might notice the wave reflecting back at the Y-junction in the circuit. This seems a little odd at first, but it's actually fully explained by the transmission line model. When the wavefront reaches the junction, the effective impedance of the line changes, so more current is required to propagate a wavefront in both directions. This means the lines begin to "yoink" more current, so a negative wavefront propagates back up to the source.
A thing of beauty. Happily, "c" seemed to be the obvious answer, and I'm glad it turned out to be right. I imagine the battery as exerting a sort of electron pressure from its two electrodes (each, in obvious directions), and the wires themselves being pipes already having content of an electron fluid. But I had no idea how you were going to demonstrate it. Totally awesome.
This was a fantastic video! The same holds true for transmission of a mechanical force through a medium involving stress waves. Its exactly identical and one thinks about the "acoustic impedance" and impedance mismatch to talk about, stress wave transmission, reflection , etc.
From an RF point of view, this all makes perfect sense, and it's absolutely fascinating to see it in such detail! I learned about this stuff studying for my HAM license tests. And when it came to things like impedance matching and especially determining whether an antenna looks like a short, an open, or something in between, I ended up just having to imagine how the standing wave looks in the circuit, and particularly things like where nodes and anti-nodes are with respect to the ends of the wires. Seeing this reveals something fascinating: _Every_ circuit is an RF circuit when it is initially turned on. DC circuits merely reach an equilibrium extremely quickly after turning on, while AC circuits don't.
@rybec My father was a HAM as well stemming from his time as a COMMS/Radio Operator in the Army during the Korean War. He was the lead COMMS operator on the front line at most of the major conflicts there...bloody ridge, heartbreak ridge, hamburger hill, etc. He was also an amazing RF/Antenna and electronics designer. His "HAM shack" and a separate 2-car garage/workshop were his experimental labs and "production facility," and there was always some sort of RF/Antenna experiment and fabrication going on. He explained the concepts (or realities) demonstrated in this video to me but wasn't quite able to present them in a way I could FULLY understand and grasp through visualization (I'm a photographer/videographer). But upon seeing this video, everything that dad was trying to get across to me through many explanations and hand-sketched diagrams finally just "clicked" in my brain. ...I think it was the added element of MOTION in Brian's simple but excellent animations. ;) Throughout my youth and later into life, I must have helped my father build, raise, lower, revise, rebuild, fine tune, and test 100's of different antenna designs of all types from 2m-80m bands and more! That experience taught me a great deal more than just simple Ohm's law, electronics, and RF principles, as it involved conceptual design, fabrication, welding, mechanics, planning, and improvisation/problem solving in a multitude of areas. All to say that I am very thankful and appreciative for all of Brian's hard work in producing these excellent videos. Side Note: FYI, if you haven't been there yet, the "Solar HAM" website is a great resource. 73
I really like the visualisations of your experiments and the intuitive insight it gives. Well done 👍 One point that I miss is that if you would terminate the single length of twisted pair with a suitable resistor (typically ~240 Ohms) the forward wave would actually stabilise at the very moment the fwd wave hits the resistor. In other words the cable has a characteristic impedance equivalent to the termination resistor. It is this characteristic impedance, determined by the distributed capacitance and inductance of the wire, that determines the initial current flow. Also this explains some initial reflections while the first segment is still "filling" due to the difference in impedance of the switched voltage source and the cable impedance. In the fork case you show there are some (negative) reflections at the very moment the wave hits the fork. This is caused by the single line from the battery now powering two wires in parallel (having half the impedance).
From a data standpoint it also makes sense. Open ends on an RS485 data bus may cause trouble. The end of the bus should have a (usually) 120 ohm resistor.
You don’t need to be REMOTELY as fast in your measurement to see that stuff! This flipping a switch example is basically crazy high frequency AC, just once
Thanks for the great video, data collection and explanation. You even touched on propagation delay. You explained transient response of a transmission line very well (twisted pair). If you drive this circuit with a square wave, you could choose a frequency that would show 1/4 wave changing from open to short and short to open circuit in each of the branches.
If you want an increased insight of why there is a backward reflection at the Y, then i Refer you to the ARRL Radio Amateures Handbook. The section on antenna feedlines and standing waves will talk about impedance changes along a feedline and how they cause a reflected wave. and the section on quarter wavelength open and shorted stubs act like an inductor or capacitor depending if they are open or shorted. I enjoyed and learned from your presentation. Thankyou.
I think twisted wires minimize inductance across proximity conductors ,data wires are twisted for that reason .Straight wires act as capacitors ,inductors , resistors and radio antennae causing fluctuations in flow of electrons for reasons you mentioned .In the first milliseconds open wire act as inductors too before voltage is saturated as there is a temporary wire load before that . Each component is contributing its share to what ends up being seen on oscilloscope ,i wonder if heat fluctuation is causing the jolts by changing the resistance ,speed of electrons across conductors .Good presentation
The disconnected pair of wires actually seem to perform as an inductive capacitor. Storing voltage at first, then feeding it back into system. I couldn't imagine how much time you spent on this experiment. But the insight you have given your subscribers is beyond time. Very nicely done.
Hi mate, I have been involved in manufacturing electric motors my whole life. At 57, that was one of the most interesting and educational videos I've ever seen. Top work.
Hats off to that video that greatly clarifies what electron drift velocity is and why it is so much slower than the electromagnetic waves'. That also helps convincing people that circuit simulators work since they solve discretized/numeric versions of Maxwell's equations in nanosecond time steps.
Yes. I must've been a lot of work. The time spent on all of this could easily be lost if you haven't done or studied and reported on research. Excellent content
As a EE, this is such an AWESOME visual demonstration and explanation of wave propagation and reflections! It gets into great logical detail without being too much for the uninitiated. As a robotics mentor as well, I am absolutely going to use this video as a primer for my students to justify why a CAN bus should not have stubs over a certain length and exactly why those 120 ohm resistors should terminate the ends of the CAN bus to minimize reflections.
Corrections and FAQ in this comment!
Check out the other channel for follow up videos, and video Q&A that I'll be posting in a few weeks with questions from here and from Patreon! www.youtube.com/@AlphaPhoenix2
Check out the Patron page if you want to support the channel, get early access to videos, and join us on Discord! www.patreon.com/AlphaPhoenix
Thanks to @ElectroBOOM for giving me a sanity check on this data a few months ago! (I hope you like the final video)
FAQ:
0) Questions about the experimental setup (including the effect of the probes on the circuit while I was measuring) are here! th-cam.com/video/sty0Y1qmgEYc/w-d-xo.html If anybody wants to recreate this project, or turn it into an undergrad physics lab. hopefully there's plenty of info there! If I can remember how to use github I'll post some of my visualization code and leave a link on that video.
1) Lots of commenters have that I'm confusing voltage and current at times, but I tried to be very careful with my language. Current is the actual motion of the electrons, and in the graphic I showed with the blue dots moving around, I'm calculating that motion based on the voltage. it's basically the current that is NECESSARY to produce those voltage patterns. I also did a measurement where I measured the current directly by placing a very small resistor at the input lines and measuring the voltage drop across it over time, so I know my calculation lines up vaguely with that, but it WAS only a measurement at one point. If somebody wants to put a quarter ohm resistor every 4 feet along a wire and measure more voltages, I'd LOVE to see the data! I'll talk about the script a bit more in the Q&A video that hopefully will be out in a few weeks!
2) When you first flip the switch, the battery doesn't actually see a "dead short". The current out of the battery initially is limited by the line impedance, which depends on the properties and dimensions of the cable. In this case, it's the same current you'd get by bridging the switch with a 150 ohm resistor!
3) A lot of people have questioned the use of the words "communicate" and "sending information". I admit I anthropomorphize a bit too much in this video, but particles and groups of particles "communicating" and the rate at which "information" can move are very important hard physics terms that don't imply the particles are thinking. "Information" here consists of things like partical position, and they pass this information between each other using the electric field.
4) Water is a compressible fluid. if water wasn't a compressible fluid than pressure wouldn't work and water wouldn't be able to flow around corners in pipes. The way I'm using it it's actually EXTREMELY compressible (in the lateral) direction because it's allowed to expand upwards without getting significantly denser. Electrons in a wire are orders of magnitude less compressible than water, but it's still worthwhile to think of them bunching up!
5) ...........keep the comments coming! i spent like 4 hours reading comments yesterday lol
The correct answer should be 'B'. Recently(I mean 6 months ago...) I saw the debate of Veritasium and electroboom and came up to that conclusion...
I have a question, in your exemple with the open circuit we see the fact that the electron are closer in one wire. what happen when you stop the batterie ? (open the interuptor in your case) does the potential rest in the wire ? making it a small capacitor ?
@@user-zp5xt8em6lI actually emailed some early data from this experiment to Medhi a few months ago and he said it was cool 😊. I’m not trying to “prove” or “discover”, anything here, just demonstrate. Electricity is very well understood by humans, it’s just hard to explain.
@@AlphaPhoenixChannel I cannot believe that you actually replied! Thank you very much!
THIS IS GREATLY APPERICIATED! 😊
@@user-zp5xt8em6lthat Veritasium video is pretty misleading. There would be some detectable trace effects due to the fields being in proximity but the full voltage only arrives later as you would intuitively expect.
I have a PhD in physics. That graph is easily the most instructive, intuitive thing I've ever seen about electricity and it's relationship to the wave properties of the electric field. Absolutely incredible experimental design and presentation.
parasitic capacitance and inductance baby!
Nice! But you actually only need to be familiar with the equations of transmission lines. A little bit above the basics of electrical engineering. ;-)
Or, elementary psychology, you've been away from it long enough and not thought about it much in that time, bits fell off the cart. But since you previously learned it, this played easy primer to relearn.
The power was inside you the whole time. *rainbow graphic
I love how the waves behave just like we expect them to -- with an impedance mismatch at the split, causing a mild reflection, and an expected difference in how the waves are reflected from the ends because of the difference in boundary conditions.
@@tamoregi"basics" of electrostatics 😊
(high level math 😬)
Excellent video, those data-driven animations are extremely clarifying. I'd never seen someone show a circuit settle into a steady state like this, thanks for putting in the effort.
Glad you liked it! (Don’t worry, I’m a big fan of math-driven animation as well)
Does it settle to a steady state? Or does it ring with ever decreasing amplitude, forever?
It's blowing my mind just how accurate the water analogy is for electricity.
Totally agree!
@@StreuB1 so there will be a moment when the interactions will reach smallest possible energy transacttions between electrons given from quantum mechanics, but in these "large" systems it is afaik effectively infinite, but mathematically you can say it is definitely not
That graphic at 10:50 is amazing.
One of the best things ever uploaded to TH-cam.
Certainly! Deserves a video on its own
I am PhD Biomedical Engineer (hons electronic) and also MD (medical doctor). Congrats on excellent video. The same thing (wave reflection) happens in your body every time your heart beats. The outgoing wave in the large arteries reflects off the capillary bed and you get amplification of the pressure (equivalent to voltage) on the leading edge of the (systolic) pressure pulse. Not only that but as you age the blood vessels get stiffer (lower capacitance) and the distal impedance increases, further increasing systolic pressure. Of course you also get a multitude of reflections at every branch. Congratulations, if you understood what I just said you understand more about this than almost all doctors.
PS. I have the exact same oscilloscope next to my monitor right now!
Amazing! I might be overthinking it, but would the electric signals through the nervous system exhibit similar behaviours as described in this video?
26:17 Not an MD. (Lay person). Visualize the effect of the electricity that is generated by the blood flow coursing through the circulatory system, how it is affected by each branch, affected by the increasing resistance as we age and the decreasing potential for optimal energy caused by stress. Visualize now how relaxation enhances potential by resolving some resistance increasing potential energy flow increasing capacity to more efficiently nourish cells of the organism increasing potential for enhanced health and wellbeing. Not looking for miracles here. Just my way of thanking you for your very articulate response to an excellent video.
That's so rad man! I totally understood that, never quiet did with the traditional examples
... maybe there are some engineers out there dealing with designing analogue sythesizers. Sure they can help!
Well this is ridiculously cool. This makes electricity make so much more sense, and what an amazing visual!!!
nerd
This is a fantastic endorsement. I recently purchased a VNA, and learning to use it helped me understand impedance and transmission so much more than anything I learned in school or from reading. This demonstration managed to be every bit as effective, which is amazing that it could be done with just a very basic scope and stuff from the hardware store. Bravo!
Hear Hear. This a demo that all scientific communicators can aspire to match. Bravo.
And then you go to uni and learn that quantum field theory shows that it was all a lie. ;)
Here is another way to think of this circuit. The open end twisted pair are a capacitor and and inductor. The normal charging constants for a cap apply. The shorted end is more of a pure inductor, again the normal constants apply.
That bar graph animation was one of the single best scientific visualizations I’ve ever seen, all the more compelling because it’s empirical, not simply modeled. Fantastic.
@@sIXXIsDesigns no 2:39 pretty much nails it
It was really good
Modeling is the death of science.
Just outstanding! Did Hon Physics to 18, and Engineering at Uni. Not once did I ever have someone so good, give such a comprehensive journey of "investigation " of all aspects of Ohm's Law with such compelling evidence of its disection! THIS is truly science explained, evidence based, and married to the theory and maths! The depth of knowledge required to be able to deliver this video is mind boggling!
Modeling - hmm? Too many ways for it to go wrong, short cuts, assumptions.........
Give me videos like this EVERY time! You don't get understanding like this from Modeling!😂
@@bluenetmarketing How would you do it
“In this video we’re _actually_ going to be able to record this circuit fast enough to differentiate between these four options.”
What a Time to be alive!
When you said "and then I spent hours stripping wire at hundreds of locations to attach the probe clips" I rolled my eyes and thought whyy?!. But your determination to follow through is what makes this so special! Brilliant combination of experimentation, video, narration, and the data-driven animations... really impressive.
Fun fact to this video: Since the waves reflect once there is a change in the wire, e.g. an "unexpected" open end because the cable was damaged somewhere, the time between connecting the battery and the the arrival of the reflected wave can be used to measure how far away the fault in the wire is (its called reflectrometry). This is extremly useful when diagnosing where cables buried in the earth are damage so that you can dig up exactly the damaged section instead of having to dig up kilometers of wires until you find the faulty section.
At the airport I work at we recently had an underground wire break. The local electrical repair company came out to locate the break. They used a trailer that utilizes the principle you described. We call it the ‘Thumper’ as you can feel it in your feet when it sends a high voltage spike into the ground to the break.
One of my friend's masters thesis used the same principle but for sound in water pipes.
@@RovDisco Thumpers like that are very primitive compared with time domain reflectometry gear. Modern form factor is a single-unit handheld (e.g. ONX-580) that can tell you exactly how far away your different faults are on the line. You'll get a different signal back for an open branch line vs. a short vs. something else...no need to even put anything at the far end of the line, although you can if you want to confirm a certain pair of wires really does take the path you think it does.
@@TwoTreesStudiotheir primitive reading is more than necessary for their purposes I am sure. They need to access a fairly large section to make repairs.
Just how accurately can that be calculated down to?
100 feet?
Absolutely amazing “footage.” Who needs expensive cameras when you can get such good data from an oscilloscope. 🤯
I’ve been trying to do the math to make something like a streak camera using oodles of repeated scope traces but finding LEDs with nanosecond ramp times is challenging xD
Sounds tough, hope you find them for the epic visual next video
@@AlphaPhoenixChannel Maybe LEDs aren't the ideal light source? Surely a spark gap could faster?
oscilloscope is a camera, for watching electron potential :)
actually i was wondering when i saw the video title, how a "camera" of any sorts could "see" electrons in a wire.
But he found the solution: multiple repetitions of the experiment, with oscilloscope probes at varying locations. Great.
After teaching basic electricity for 35 years or more this is the best explanation and visualization that I have seen regarding current and current flow and how the wire bunches up its electrons and releases them quickly or slowly and remember 6.25 million million million electrons flowing through a wire in one second equals 1 A so electricity is it all that magic you can actually see it and measure it
Wow. I have a Ph.D. in Electrical Engineering, and I am impressed at how clear and effective this video is. Excellently done!
Did you already know a lot of this information, or did you learn something?
@@hydropage2855 most of it I already knew, but not from a single source, more the total of the education and experience I have. I did not realize the potential wave reflected multiple times across a DC circuit, though, I figured that only happened once, so that was cool to see.
@@daniellewis3330 I actually feel like it would’ve made more initial sense to me that it would happen many times, since pretty much everything in the world boils down to oscillations in one way or another, mathematically I’d assume it would “take forever” for this to settle down
@@hydropage2855 fair
IMO this is hands-down one of the best physics channels on TH-cam. Your ability to turn highly abstract and complex concepts (like the "speed of movement" which is a video I'll never forget because it blew my mind) into real-life experiments using actual measuring equipment is just amazing.
I like it when someone takes a seemingly impossible problem, and breaks it into easily solved chunks. Brilliant!
The intuitions for (S)TEM microscopes and voltage is what sold this channel to me. Now it’s going to get better.
Your vids have already changed my understanding of electronic fundamentals, but this visualisation in particular absolutely took it to the next level. Thanks.
I wish my children would understand that learning should be fun.
Check out the video looking glass universe released on refraction. It really helps to understand the electric field and what photons really are.
@@chrisspere4836i mean it's your job to make it fun for them, no?
This video should be played in every school, I'm an electrician and never saw this explained this good
I've been utilizing "electricity moves like water" as a basis for troubleshooting and planning for decades, this is be best description, example and proof of this thought process I have ever experienced. Well done. Subscribed.
it works for practical application but as Veritasium showed, it doesnt act like that. its really not intuitive how it does work.
It's so awesome how you genuinely dig all of this -- you could have talked about it for hours! People with your enthusiasm make the best teachers! THANKS!
As an RF Engineer, the stuff you're talking about is my daily bread an butter. Still, I've never seen such a good visualization of electromagnetic waves, let alone based on actual measurement. Really cool and educating, even for professionals!
I'm also and engineer for a prominent company that designs/produces RF power supplies for plasma sputtering, semiconductor etching, metrology, etc. However, I design and write regression tests for our firmware. Specifically, I test the product that does dynamic impedance matching between power supply output and plasma load. Who do you work for? I wonder if we work for the same company ;)
Reflections are a big part of our zeitgeist, and I agree that this video does an excellent job visually representing what reflections are and how they work.
@brentsmith7013 what I found interesting when first learning about RF, is how much more consequential everything in the circuit is. Like an axial resistor isn't just a resistance value. The leads and film material also act as little inductors and a capacitor in the circuit (to your point). I have a ton of respect for RF engies, because they are doing calculus vs me doing basic algebra.
Also an RF engineer, and also very impressed! The old adage that only a real expert can explain things simply really applies here.
Hobbiest RF guy here. I'll be using this video to talk about wave propagation in a transmission system, why we open/short/load a DUT, and more when I teach potential licensees...
Speaking of RF, I'd love to see this experiment repeated with Litz wire so that we can compare them. I think that would be super interesting.
I've seen the "ringing"/"bouncing" oscillation effect on an oscilloscope when connecting wires before but to see it graphed out spatially like that is incredible
I didn’t REALLY understand it until I could see it spatially. This is one of those cases where figuring out how to make a visualization ends up teaching me
The impedance-matched version is WILD th-cam.com/video/RkAF3X6cJa4/w-d-xo.html
@@tripplefives1402interesting
@@tripplefives1402 nice, thanks for that comment, it just clicked in my head for understanding antennas, totally makes sense after this video!
This may be the best vid of this sort I have ever seen. The beauty of not only the knowledge it discovers, but also how it was discovered and the joy of the experimenter literally have brought me to tears. I simply cant express how beautiful this is to me at each level and in the aggregate.
I've worked with electricity my entire adult life, and I learned more about the theory behind it (as opposed to the practical application I use daily) from this video than any of the class I took. The visualization of the current signals propagating through the two circuits blew my mind
I have a bachelors in Electrical Engineering and have worked in the profession for 34 years (retired). I have never seen electricity explained this intuitively in college or at my job. This was awesome. The similarities between fluid and electricity behavior are so useful to help understand electricity. It's a very tough thing to grasp due to how fast things happen on an atomic level. You figured out a creative way to capture it.
Agreed. I struggled with these concepts initially in college, and an explanation like this illustrated the concept perfectly.
Yeah, I always pictured the initial wave explaining switch voltage spikes, but I always assumed it would dampen much faster than that. Seeing the electron loading bounce back and fourth almost 4 times before being dampened to equilibrium with the motive force was impressive.
My understanding is the electrons do not move , the electric field moves out side finds the electron at end of wire or switch junction whatever , They all teachers say electrons move yes but not in the way we think about movement in that way they don't
@@rolandhawken6628 Electrons are moving from one pole of the battery to the other in an electro-chemical-thermal reaction.
@@runbigfoot I was referring to wire
As a physics educator at a university, I love this video for so many reasons. First and foremost, this was amazing science done right. You presented a problem, made a set of competing predictions, established what data you were going to collect and related your predictions to your data (you said what we expect to see in every different case), then you took a copious amount of data (p
Nice comments, and yes, thanks for your reference to Mr. veritasium who instantly came to my mind while viewing this......for all the wrong reasons !
I’m a glutton for data 😁
My favorite part of this experiment is that it demonstrates that, yes, electricity is made of actual "stuff" while also demonstrating that the actual information which defines a circuit must somehow travel at some speed.
@@AlphaPhoenixChannel Is this research correct? Unlike a simple Y wire with closed and open ends, the developed circuit already becomes an “inductive” circuit, moreover, with a connected oscilloscope completing the circuit.
верно ли это исследование? в отличии от просто Y провода с замкнутым и разомкнутым концами, развитая схема уже становится "индуктивной" схемой, более того с подключенным осциллографом замыкающим цепь.
@@gt_xpert I am very from an expert but my understanding leads me to believe that all circuits have some degree of inductance (because they all involve current flowing and therefore create magnetic fields). Furthermore, the question wasn't what happens in this exact set of of wires with this exact resistance and this exact inductance, it was: "how does information travel in a circuit" which is much more general and I believe very very very well shown here
This might be the best video I have seen on YT. I can see how much work you put into it. And seriously, thank you for doing it. I studied EE and I left school not truly understanding it: none of this was covered in school, at least not in a way that made electricity intuitive. Years later, I feel so much more informed about what I studied. Thank you for your dedication, curiosity and creativity.
Dude!!!!! THAT WAS AWESOME!!! When I saw that very first animation of the flow levels spiking and reflecting, starting at 10:23, along with the spot-on ethereal music.... THAT WAS MESMERIZING!!! I can FINALLY visualize how DC behaves in circuits... and I've been working with electricity for 50 years!
In this circuit, the twisted pair functions as both a resistor and capacitor. The initial inrush current is taken up by the capacitance. When it reaches steady state, only the resistance is applicable.
You have essentially reinvented a time domain reflectometer (TDR). It uses the reflected pulse to determine the length of a wire. It can also determine the distance to a fault or splice (useful for locating a fault or determining that a signal cable has been tapped). The same principle works for fiber optics. For security purposes, an easily broken and nearly invisible unsheathed fiber is woven through a barrier. When the barrier is cut, the fiber is broken and the exact location of the break is determined by the TDR. Hint: Don't ever try to break into a Google data center.
That's exactly what they did when my glass fiber connection was broken. I didn't understand how the measurement tool worked. He explained it, but to me, it didn't make sense at the time.
Thanks for this. With this video and your comment, "reflectometer" becomes as easy to understand as echolocation.
So the ringing after the inrush spike is because of the stray capacitance and inductance forming a tank circuit right? Resonance at the natural frequency
DAMN! I was just about to mention the TDR. Navy avionics school, 1975.
So if I understand correctly, the initial reflection at the fork is caused by resistance(impedance?) change of doubling the wire cross section? If the forking wires were smaller and summed to the cross section of the initial wires there would be no reflection at the fork?
Reinvented TDR? You can go back further and explain why turning on an amp (audio or radio) without the (speaker/antenna) connected can destroy the equipment instantly! (ok, in a few nanoseconds, when that voltage inrush spike comes back!)
I’m an electrical engineering student. I remember learning this in circuit analysis but this visualization is so much better than the things we had.
I am an engineer (electronics) and I hated transmission lines. I got around that after someone told me to stop looking at the equations as an engineer and more like a mathematician.
If your school offers it and you're at all interested in this type of thing, I'd recommend taking High Frequency Systems. No doubt one of my favorite classes.
i am not an engineer but i am assuming that this is a representation of inrush current?
@@Hullad1379 Transient response.
I’m a sparky and you’re exactly right! I wonder if an led would light for a nano second if forward biased on the open ended pair, due to the rolling voltage gradient?
This is the kind of video that defines the need for TH-cam. This is awesome. Thank you for doing this!!
That is an amazing, intricate, time consuming and number crunching experiment and you basically proved that electric waves behave the same as ultrasound and other waves.
For over 15 minutes I was yelling at my screen "CAPACITANCE!" It's almost like you heard me...
This channel is like a saving grace to people who already know the math and feel the physics but don't quite get it. It feels so good to understand what you thought you knew.
Yes, it remembers me what I learned decades ago on microwave wave guides and printed circuits. But it was all maths and fields back then, and harmonic signals. I never figured what could happen to electrons in conductors, specially the pattern of "charged" wires in an open-circuit DC line.
What a cool visualization, huge props for tediously collecting all that data! Something about seeing the real data moving in waves like that is just _so awesome_!
there were multiple times I think i audibly gasped looking at graphs while working on this project. the first was the test animation for propagation, which was SO satisfying, but my favorite was actually the time I accidentally impedance matched the circuit on the table and finally understood - I'm disappointed I ended up relegating that bit to the second channel but I couldn't explain it without more math lol
by the way, your injector video was fantastic. I really want to try to make a liquid fuel engine one day
Greatest video of this topic I've seen. It shows the field levels, the electron compression and movement, the waves, reflections, and steady-state result, all while remaining empirical! Seeing the slope of the graph in relation to the electron speed and density is awesome.
This video is so satisfying. It brings the hydraulic analogy to another level, and it looks like putting electricity under a microscope, figuratively and very much literally.
Holy cow! I have a masters degree in physics and this is one of the most intuitive and understandable explanation of electron flow I've ever come across. I'm amazed on how much information you could gain with this "basic" setup. I also love your systematic approach and the brakdown of the system. Very well done sir!
It is not electron flow, it is the propagation of guided EM waves on the wire.
@@msf60khz at least i know now physics majors are not gonna steal my electrical engineering job
@@msf60khzthey’re the same thing 🙃
@@flowildfellow electronic engineer here - @longnose154’s model is perfectly accurate because electron movement and wave propagations are analogous models for each other - basically half of the point of this video is to explain this 🙂
THERE ARE NO ELECTRONS. CHARGE IS BOTH POSITIVE AND NEGATIVE. METALS HAVE FOUR FIELDS. +/- STRUCTURAL AND +/-FREE CHARGE. WHEN YOU CONNECT THE BATTERY THE INDUCTION FROM THE POLES ALTERS THE RATIO OF +/- STRUCTURAL CHARGE COMPENSATION AVAILABLE FOR EQUALIBRIUM CONDITION OF THE METAL AND THE PLATES OF THE BATTERY.
ALL MATTER IS MANIFESTING FROM THE AETHER CONTINUOUSLY. NEGATIVE AND POSITIVE CHARGE FLOW FROM THEIR RESPECTIVE POLES OF THE BATTERY TO COMPENSATE THE INDUCTIVELY MANIFESTED ALTERATION OF +/- STRUCTUAL CHARGE CAPACITY IN THE METAL OF THE WIRE. AETHER/HEAT IS UNDIFFERENTIATED +/- CHARGE WHICH DISSIPATES LONGITUDINALLY NOT ELECTROMAGNETICALLY FROM THE WIRE. THERE IS NO MAGNETIC FIELD AROUND A ROUND WIRE, OTHERWISE THE WIRE WOULD BE ATTRACTED TO AN IRON SURFACE. THERE IS AN ANISOTROPIC PERMEABILITY TO MAGNETIC FLUX CONCENTRIC TO A ROUND WIRE OF THE CLOSED CIRCUIT. A FLAT CONDUCTING WIRE WILL ATTRACT IRON AS WILL TWO PARALLEL WIRES CONNECTED TO THE SAME BATTERY POLES AT THE SAME ENDS.
This deserves a standing ovation. This should be *required viewing* at EE classes, enough said.
This is just incredible work on the split wires and then the tapping with all those measurements and the graphs. This is just unbelievable work. I did not think we would get that detailed of an answer and hadn't even made a guess. Just amazing work.
That graph at around the 12 minutes point is absolutely fantastic. It really shows how your models with water are a very good representation of how the electric will behave.
Fantastic work thanks for making these videos.
Wow. Just wow.
As an electronics engineer I can say that without the shadow of a doubt this is the most easy to understand, visually impressive video about electricity I’ve ever seen - and the insane amount of work that this must have required just drips out of every pore.
And I have never actually thought about how the waves flow… this is insanely interesting! Thanks so much!
This was demonstrated in my high-school Vocational Tech Radio - TV Repair class using Tubes & dual trace oscilloscope. the effect described here has implications in pulse & wave shaping for mil-spec IC substitute and circuit cross-talk. I am solving an ELF (Extremely Low Frequency) innovation where this demonstration is one factor in the solution. PhDs can be a challenge for explanations. 😊
In the early '80s, I built a semiconductor company to manufacture semi and full custom analog and digital ICs. Our designs were in everything from toys to spacecraft. It must be so much easier/more-fun to learn now, than then. I'm obsolete as hell, but this was fun to watch.
@@EatMyOats Please make sure to upload a youtube video about your project once it's public! Thanks!
@@RickMcCargar In university a professor explained the concept of "software defined radio" to us. We were used to calculating antennas and frequencies and at first thought he must be joking.
Then showed us his gear: a room full of equipment worth hundreds of thousands.
Today I have one in a drawer somewhere, worth 150 EUR and the size of a box of cigars.
But to me, honestly, it still borders on black magic that this concept actually works.
I'm a technical trainer who was wondering why an open circuit in a car's network system caused a huge voltage spike on the oscilloscope. This video single handedly demonstrated and proved what was going on and why. This was exactly what I was looking for - thanks so much!
CANBUS is super interesting stuff, I've spent many months studying it. This video re enforced to me how electronic networking is just voltage pulses of "information" sent down the line and detected. It's the same concept with how the battery "figures out" how much current to send down the line as it is in actual networking systems. Voltage is sent down the line and feedback is sent back.
@@kc7affsame with a process called "TCP windowing" in networking. The TCP tries to find a confortable medium between super fast data stream and dropped packets. (Source networking engineer)
Now I understand why my truck's poor electrical from past owners causes issues for me all the time. :)
Mate; you have just cleared so very many mental blocks, not just regarding electronic influence propagation - the falorn intent of watching the video in the rirst place - but in a number of other significant respects also....
I have struggled with a number of mental processing issues for more than six decades and have the complicated history of my life to show for it.
The inspirational manner in which you have thought through your question; have aquired so many and varied tools and apperatus whilst mastering thier use and application to a more than adequate degree of comprehension and competancy; translated all into a material construct, visible, influenceable, testable; presented with absolute clarity, confidence and humour ..... I felt pathways opening up. I do not know if it will last, but I will now see if I can remain, to what ever degree or extent, within this splace which occupies the other side of the divide.
Really, thank you so very very much:
And I now get the piece of the puzzel where the propagation of electronic influence fits to boot !!
Really, thank you and congratulations on the outstanding quality of your project :)
This has blown my mind. You've taken a bunch of difficult electricity concepts (some of which have been argued about for years) and cleared them up using a brilliantly designed experiment and clever visualisation technique. Really well done!
The bouncing and ringing are due to capacitance and inductance effects of the imperfect conductors. The two combined give you reactance, you measured it beautifully. This is also why we use termination resistors in data lines like RS485 at dead ends in order to avoid bouncing waves of signal causing interference.
It's not that the conductors are imperfect, it's that they exist at all; even a superconductor inherently has inductance and capacitance with the world around it, and a sole superconductor not in a transmission line would still deal with the characteristic impedance of free space. He's replaced the characteristic impedance of free space with the characteristic impedance of the twisted pair, but the dynamics are due to electromagnetic interactions of the current wave with itself, not resistance or imperfections in the line. It is the impedance mismatch at the end that causes the reflection.
For me it's easier to understand the behaviour of the disconnected wire considering the twisted pair forms a big capacitor. Huge voltage at first, as the capacitor is not charged. As it charges, voltage drops closer to zero. And all the resistances, inductances and capacitances make up effectively a RLC oscillator.
why such presentations an animations are not givento people in the school..?
@@MrMassmaker They are, we performed similar measurements at EE school to understand conductors better in real world applications. In my case it was a spool of wire that we characterized with a signal generator and an oscilloscope.
Awesome! As a 40+ year electronic technician I knew the answer, we just always accounted for this as an initial "spike" when energizing a circuit, sort of "filling the pipes" so to say. Your visuals really brought it home for this old "sparky".
Old Sparky, so when I was a kid way back, parent or grandparents would say, "Don't keep flipping the lights on and off, it uses more electricity!". Is that because the initial first few waves it does use more energy than needed before it settles in? Now once they told us this we did it many more times because that what kids do. But they were right!
I'm a mechanical tech and I understand the concept of inrush current.
This video was really good. I also deal with high pressure fluid circuits with dead sections that start and stop and this will be in back pocket from this day forward.
@@TUTruth The initial few waves don't matter much for power consumption. The reason they told this, is because the filaments in incandescent light bulbs change their resistance with temperature. When they're cold, the resistance is low and a high current flows. Once they heat up the resistance rises and the current drops. When you kept flipping the lights on and off, the filament didn't stay hot, so more current could flow
@@TUTruthFlipping the switch on and off actually uses less electricity overall. Light bulbs use a lot of power when you first turn them on because the resistance is very low at room temperature, then the filament heats up to maybe 2700 kelvin (almost immediately), resistance goes way up with temperature, and current goes down.
This is why you can't guess the watt rating of a light bulb by measuring the resistance with an ohmeter. Try it. Measure a 100W bulb. The resistance at room temperature will make you think the bulb will use 10x that amount of power, but this is only true for a fraction of a second.
The real reason to not flick the lights on and off is that it damages the bulb. Any time you've seen a bulb burn out, it was when you tried turning it on. They very rarely burn out while they are already on.
Also true for fluorescent lights. Striking the arc wears out the tube.
@@shawn576: Thank you. Excellently explained.
I admire your tenacity and determination in pursuing how to explain this problem to non radio engineers, well done. As a retired radio engineer, we think in terms of the characteristic impedance of a line, its terminating impedance, and consequent reflections. That makes it easy.
By the way, regarding the short circuit on the water line, the only way to replicate that is to have a very wide hole at the end so that the water can flow out without any height (= voltage) restrictions. My apologies if you already mentioned that.
55 years ago, I was taught by Western Electric and Bell Telephone instructors how to trouble shoot telephone cable. Much of this was already known but not very well explained. This does help visualize the way it works.
This is the most interesting thing I have viewed in years. It is the sort of thing I "knew" but didn't really "know". One approach for the water analog is to open the slot horizontally instead of vertically. Now, I am going to go back and watch this, fully, again. Very interesting!!
I've been a PCB designer for 17 years, some of my best training was a hands on hydraulics class that I took at a tech college. It's surprising how well the analogy holds up. I'm just an electron plumber. I love your video and really wish I'd seen something like it my first try through college physics.
The great thing about this channel is that it's not about fancy production values. Your technical skills and enthusiasm carry it all by themselves. Thank you for the effort!
I can hear Master Piandao going “it certainly wasn’t your skill” 😂
Wow, I have worked in the electronics field for over 40 years and never gave this a thought. Thanks for doing such a great job illustrating what happens. Loved it. This also helped me appreciate propogation delay in conductors/coax. Keep up the good work!
This is one of the coolest videos regarding electrical propagation I have ever seen. Congrats! Even though you are dealing with a DC circuit, while it stabilizes it is behaving like an AC circuit with the transient wave reflecting back. So cool.
I have a physics bachelor's and i think this video should be shown in the first year. It really helps build an intuitive understanding of several concepts that I always struggled with until now. THANK YOU SO MUCH! It also begs for follow-on experiments such as demonstrating wire configurations with high versus low capacitance. I love that electron gas pressure propagation is so visible and that electron drift velocity is definitely NOT the same! This is inspirational experimental physics at its best capable of inspiring young enquiring minds to think about the phenomena in our daily world that we usually take for granted. SUBSCRIBED! And why do I discover this great channel only now?! All the best, Rob in Switzerland
A part of the effect of capacitance is shown in this video: th-cam.com/video/9hhcUT947FI/w-d-xo.html
Haha, welp, I'm a first year EE student studying in Switzerland right now 😅 very glad to have found this channel indeed, super inspiring stuff
This is freaking great. The video itself does not show, but the amount of effort it must have taken to get all these measurememts.... great job, hope this gets some nice exposure, because this really clearly explains how electricity works.
This all had to take FOREVER to set up and refine
I sadly don't have a timelapse of taking all the measurements multiple times, but here's a video with a lot more detail on the setup! th-cam.com/video/sty0Y1qmgEY/w-d-xo.html
Time to reach out to LeCroy and Keysight and get them to sponsor you with a many-channel scope 😂. But seriously, NI makes 12 and 24 channel “scope-DAQs”… 😊
Thank you for putting such a massive amount of work in collecting the data and turning them into those visual graphics! Makes it SO much easier to understand!
I love it how much effort has been made in visualizing this. Thank you
That data-driven animation at 10:47 is brilliant
This is beyond incredible. The amount of time you spent on something so ubiquitous and distilled it down to such an easily digestible morsel of information is absolutely brilliant. The animations were so fascinating to see, and I had chosen B for my answer, and when you showed the water flowing in the channels I nearly second guessed myself lol. Incredible work man, I look forward to your videos!
Could not agree more.
I also guessed B, but C was what I was picturing as I did. I think the wording was a bit confusing, as I was hedging toward B because it's a more physical description, where C is more anthropomorphized.
I love how you give us a simple question, yet difficult to answer. Love your video. Will watch it when i have more time.
My automotive electrical instructor I had in college described electromotive force / voltage as a push. Now, I have a clearer way to picture it, as well as an appreciation that he explained it so well.
This is why the TDR (Time Domain Reflectometer) is so cool. It displays the "echo" of the electric pulse bouncing off the break. And that's how we used it in the telephone industry to find the distance to a cable break (or see the "bump" of a wiring closet on the way to the actual cable end elsewhere farther down the "circuit")
It doesn't just work with electrical signals. It works with optical signals too, although for shorter runs (like in planes rather than between neighborhoods) a frequency domain reflectometer, which doesn't rely on a pulse, but a constantly changing frequency, provides the necessary resolution.
What do you mean with shorter runs? In optics typical OTDR can measure fibre cable break distances 100 km or more easily. The longer the cable, the more time you have "to measure" but the more sensitive detector is needed.
I remember the wave of understanding when I was a kid and the guy that came to fix the phone explained how he could measure the distance to the break in the line.
Brilliant!
Dude. Hats off for you connecting the oscilloscope to all these points. That is dedication, great video!
Yeah that's one of the best part.
Anyone who's worked in an electronics lab understands just how painful that process would have been
Man, your videos made me have a total new vision about electricity!!! Love the way you you show the graphics, and the analogies!
That's an awesome video. You basically made a wire-version of a slow-motion video of a lightning strike! In a lightning strike, you see lots of tendrils explore all possible paths towards the ground until one connects. Then, boom - all other paths disappear and the lightning bolt appears between the ground and the cloud.
I have worked with computer networks since 1994. Back then (1994), I used to *try* (badly) to explain why leaving the terminator off an coax Ethernet cable causes reflections and can be detected by observing an increased voltage. Now, almost 30 years later and after watching this video, I finally understand those reflections. You do awesome work Brian, keep it up and keep inspiring new mathematicians and engineers.
cheaperNet (UTP) and switches made EtherNet networks a lot less bizarre, a lot easier to diagnose, than coax cables with a PDP-11/23 at the centre of the tangle (experienced in the early 1980s).
the NBN (VDSL, in this case, to the nearest optical POP) router connecting this home to the world has four 100-megabit UTP sockets on the LAN side, and WiFi, yet copying bulk files between nodes is much faster across two pieces of blue string than involving WiFi anywhere, as any competition for WiFi bandwidth rapidly bogs things down.
This has been an excellent series, I am an avionics technician, we have a lot of rules of thumb, do this don't do this, that keep our circuits working. But few can explain the underlying why's in a coherent way. For instance we terminate unused data busses with terminating resisters to stop "reflections", here I see exactly what it is that we are stopping, return waves that stomp all over our signal.
How do I become an avionics tech?
@@mrblank-zh1xy I did it by joining the Navy. I worked on the AWG-9 radar system for the F-14 from 2001 until it was decommissioned in 2006. I also cross-trained to the F/A-18's radar systems, the APG-65 and the APG-73. Free training, plus a GI bill on top of that. I also went to 2M school (miniature/microminiature electronics repair) to round it all out.
Is that a 1553 data bus you're talking about?
That graph deserves a video on its own, seriously!
You have made my day! The clarity this analysis is and the illustration of the conclusions drawn is beautiful thing. Thank you.
I don't think people realize exactly HOW much WORK you had to put in to come to the result being depicted in this video.
Like, the amount of testing and changing... building those frames, twisting the wires, splicing, connecting the probes, getting the data, repeating it again and again to get many datasets, trying out different ways to animate the data, comparing the animations to determine which animation looks best, comparing the datasets to determine which dataset looks best when animated, recording all of the footage, editing the footage, building the liquid model, etc etc etc.
I could go on and on!
I'd imagine this whole thing took a good part of a month.
Like.... if you were to do _only_ work on this project 24x7, it would've taken nearly 3 weeks of working 24x7 without eating or sleeping or doing anything else!
Hats off man, hats off.
This is insanely cool educational content. If I was an electronics/physics teacher I’d 100% show this in class. Rock on Mr. Phoenix!
I was just about to type "that's insanely cool" then saw your comment. Cheers to thinking alike!
That was truly amazing. Who would have thought there was all those interactions going on. Thank you for all that work. Long may you continue.
Nice demo. When I was teaching transmission line propagation, it was always quite hard for students to understand the principles of the TDR, because they were SO used to the ideas of DC circuits they were taught in EE101. The idea that applying a DC voltage at t=0 initiated a wave, was very different from their understanding of a static DC circuit, and transient voltages were only considered to be the result of L & C lumped circuit elements.
This animation, the setup, and the measurement must've taken a lot of time to get right. This level of patience is something I aspire to have after watching this incredibly enlightening video. You are my hero. Thank you, from the bottom of my heart! This video should be a must in all undergrad curriculums.
You're*@@My_Fair_Lady
@@AlphaPhoenixChannel lol
@@My_Fair_Lady
But... how would someone _𝘂𝗻successfully_ pull something off?
I have unsuccessfully pulled off _so many stickers_ @@-danR
This is the most complete explanation of wave propagation and line impedance concepts I ever saw so far. The idea is sooo cool. And yeah, I feel the same way regarding availability of relatively cheap devices that allows for literally light speed measurements on a bench. What a time to be alive.
as I have just completed my high school and i watch many videos on youtube related to science, electricity, physics,etc. but only some of them are my favorite channels and one of them is yours. I find your videos answering many of my doubts related to electrodynamics and electrostatics, very informative with deep analysis experiments and not just talking upper upper like most youtuber do to make their videos understandable for more mass audience and ignoring the audience that wants more details.
I hope you keep up with your experimental videos.
😊
An absolutely amazing video. It is one of the best experiments I've seen in years. I can't believe that you manage to film the behavior of electrons with such a simple, but so well-thought setup. Thank you very much!
I'm a commercial service electrician, and this video has cleared up some VERY perplexing issues that I've run into in the past that were causing some sensitive electronics to act up. At the time I was able to "fix" the issue with luck, and trial and error but now I have a pretty good idea of what was happening.
You learn something new every day!
Can we know about what was the problem exactly and how you solved it? I am not an electrician but it sounds educational
I second @painlessskun3959 request :)
Fantastic video! I have a master's degree in EE and work as an RF/antenna engineer and this is probably the best demo I've seen of these EM concepts. Amazing job breaking it down in such a way that I think anyone could understand. There's definitely some really interesting and cool material in the transmission line and RF realm which builds fairly well off of this, I'd love to see your take on antennas (and selfishly think whatever demo you'd come up with would make it a LOT easier for me to explain my job to people lol).
A video on antennas would be very cool
Indeed... Even this DC circuit was AC for a little bit... RF is so fascinating. :)
Agreed! I felt pretty good figuring out which option was the right one but I can only attribute that to my knowledge gained from Amateur Radio and antenna propagation theory. I would be fascinated to see this on an antenna with RF signals but also to include actual electron flow as well. I've always thought of electron flow through wire as similar to water, but have always had a hard time equating that to RF in a wire. I would love to see it mapped out like this and the two compared. Totally geeking out right now.
I am an rf tech and I suspect that brief moment of current starting through the circuit on the open branch the energy radiates. Looks like a dipole antenna. I paused the video before finding out the solution. I have done this thought experiment with millions of miles of open pathway on a circuit. How in the heck does the circuit know it’s a dead end without violating Einstein’s theory that no disturbance can go faster than the speed of light? From another perspective, the time factor may help explain why energy has to radiate from an antenna in the first place.
@@artofplanets Because Einstein is NOT the END-ALL definitive source, or Law Maker. The Universe is. And Laws can change when the environs reach states we dont ever (or hardly ever) experience, percieve, or theorize about. And even then, we dont always predict events with 100% accuracy in these areas.
Short answer: EINSTEIN was wrong, and he even admitted it, if you look hard enough youll find it out there. The SPEED of LIGHT is NOT-EQUIVALENT to the Universe's "Speed LIMIT". There is no TRUE "Limiter" of Speed Full-Stop. Theres only changes of existent forces due to the current 'moment' and its environment/medium/surrounds. And that leaves A LOT of variation, some of which we still cant actually test for.
I think this is happening in my ham radio antenna, we refer to things like "SWR" or standing wave ratio describing how "resonant" a given antenna is, and therefore how efficient. It looks like a standing wave "sloshing" like water in a beaker that waves back and forth until settling. Very thought provoking video!
1. I love that there are people who are highly intelligent, with complimentary complex and multifaceted skills.
2. I love that I am sometimes able to comprehend what they have to teach/share.
3. I love that these people, including the Americans, use the metric system.
4. Today my day has been full of love and, interestingly... its 100% electric ❤
This is hands-down the best science video I've seen on YT. I'm in awe about how much time you spent conceiving, building, testing, documenting, visualising and then creating this video!
There is one video where he says how much footage he omitted.
I love that you build the analogous water circuits IRL and then explain their limitations. Exactly what I try to do for my electrical students. This demonstration is perfect for my avionics students when discussing aircraft radio transmission lines like coax cables between equipment. Thank for investing the time for all of us!!
And it should show well why you need a resistor to terminate dead ends, to stop those reflections!
This is pretty amazing. I am an RF Engineer, and I have never seen a better illustration of my work. This really does tie into transmission lines well....Very impressive.
I swear, i've seen the slow mo guys show up in so many channels besides theirs, and I'm greatful that they're willing to share their insanely expensive gear with other channels. Hell, idk if they rent it, but if they do, that's a great way to recoup the cost.
The amount of work you put into your videos is breath taking. Your real life models (both wire and water) and the animations are simply brilliant.
And the graphing was a lot of work too
That's such an amazing visualization of voltage waves through wires. Thank you for putting this together!
As an electrical engineer, I saw this in my suggested videos and was in my head critiquing YT's recommendation algorithm for giving me what I thought was such a low IQ video recommendation on basic Electrical concepts. It kept showing up on several occasions, and eventually my curiousity of why I was getting such a lame recommendation caused me to click to scrutinize what value this video offered that caused it to be perpetually in my recommendations. Was pleasantly surprised at the way such a simple experiment offered a wealth of intuitive insight into how physics and electricity works, specifically circuit network impulses. Got to say, I was entertained and delighted by the educational value. A+
Fantastic! I don't normally add a comment. Not in Years. But you have demonstrated electron flow in a way that anyone could understand. I hope you teach professionally. Thank you for your efforts.
At 20:38 (and in other places) you might notice the wave reflecting back at the Y-junction in the circuit. This seems a little odd at first, but it's actually fully explained by the transmission line model. When the wavefront reaches the junction, the effective impedance of the line changes, so more current is required to propagate a wavefront in both directions. This means the lines begin to "yoink" more current, so a negative wavefront propagates back up to the source.
I love the scientific use of "yoink"
Really appreciate the amount of effort you put into these experiments!
A thing of beauty. Happily, "c" seemed to be the obvious answer, and I'm glad it turned out to be right. I imagine the battery as exerting a sort of electron pressure from its two electrodes (each, in obvious directions), and the wires themselves being pipes already having content of an electron fluid. But I had no idea how you were going to demonstrate it. Totally awesome.
This was a fantastic video! The same holds true for transmission of a mechanical force through a medium involving stress waves. Its exactly identical and one thinks about the "acoustic impedance" and impedance mismatch to talk about, stress wave transmission, reflection , etc.
From an RF point of view, this all makes perfect sense, and it's absolutely fascinating to see it in such detail! I learned about this stuff studying for my HAM license tests. And when it came to things like impedance matching and especially determining whether an antenna looks like a short, an open, or something in between, I ended up just having to imagine how the standing wave looks in the circuit, and particularly things like where nodes and anti-nodes are with respect to the ends of the wires. Seeing this reveals something fascinating: _Every_ circuit is an RF circuit when it is initially turned on. DC circuits merely reach an equilibrium extremely quickly after turning on, while AC circuits don't.
@rybec
My father was a HAM as well stemming from his time as a COMMS/Radio Operator in the Army during the Korean War. He was the lead COMMS operator on the front line at most of the major conflicts there...bloody ridge, heartbreak ridge, hamburger hill, etc.
He was also an amazing RF/Antenna and electronics designer. His "HAM shack" and a separate 2-car garage/workshop were his experimental labs and "production facility," and there was always some sort of RF/Antenna experiment and fabrication going on.
He explained the concepts (or realities) demonstrated in this video to me but wasn't quite able to present them in a way I could FULLY understand and grasp through visualization (I'm a photographer/videographer).
But upon seeing this video, everything that dad was trying to get across to me through many explanations and hand-sketched diagrams finally just "clicked" in my brain. ...I think it was the added element of MOTION in Brian's simple but excellent animations. ;)
Throughout my youth and later into life, I must have helped my father build, raise, lower, revise, rebuild, fine tune, and test 100's of different antenna designs of all types from 2m-80m bands and more!
That experience taught me a great deal more than just simple Ohm's law, electronics, and RF principles, as it involved conceptual design, fabrication, welding, mechanics, planning, and improvisation/problem solving in a multitude of areas.
All to say that I am very thankful and appreciative for all of Brian's hard work in producing these excellent videos.
Side Note: FYI, if you haven't been there yet, the "Solar HAM" website is a great resource.
73
Really true! I think exactly the same from a point of view building SMPS topologies. Especially the snubber circuits are sometimes weird.
The RF analogies can to my mind as well. Pretty cool stuff. GROL
I really like the visualisations of your experiments and the intuitive insight it gives. Well done 👍
One point that I miss is that if you would terminate the single length of twisted pair with a suitable resistor (typically ~240 Ohms) the forward wave would actually stabilise at the very moment the fwd wave hits the resistor. In other words the cable has a characteristic impedance equivalent to the termination resistor. It is this characteristic impedance, determined by the distributed capacitance and inductance of the wire, that determines the initial current flow. Also this explains some initial reflections while the first segment is still "filling" due to the difference in impedance of the switched voltage source and the cable impedance. In the fork case you show there are some (negative) reflections at the very moment the wave hits the fork. This is caused by the single line from the battery now powering two wires in parallel (having half the impedance).
From a data standpoint it also makes sense. Open ends on an RS485 data bus may cause trouble. The end of the bus should have a (usually) 120 ohm resistor.
Would love to see this same visualization but with AC current! Like antennas and resonant frequencies etc would be awesome ❤
I'd like to add this old movie from 1947 for those interested in transmission lines:
th-cam.com/video/JHSPRcRgmOw/w-d-xo.html
You don’t need to be REMOTELY as fast in your measurement to see that stuff! This flipping a switch example is basically crazy high frequency AC, just once
Extremely well done. Answers important questions. I am seeing it useful for QC.
Thanks for the great video, data collection and explanation. You even touched on propagation delay. You explained transient response of a transmission line very well (twisted pair). If you drive this circuit with a square wave, you could choose a frequency that would show 1/4 wave changing from open to short and short to open circuit in each of the branches.
If you want an increased insight of why there is a backward reflection at the Y, then i Refer you to the ARRL Radio Amateures Handbook. The section on antenna feedlines and standing waves will talk about impedance changes along a feedline and how they cause a reflected wave. and the section on quarter wavelength open and shorted stubs act like an inductor or capacitor depending if they are open or shorted. I enjoyed and learned from your presentation. Thankyou.
I think twisted wires minimize inductance across proximity conductors ,data wires are twisted for that reason .Straight wires act as capacitors ,inductors , resistors and radio antennae causing fluctuations in flow of electrons for reasons you mentioned .In the first milliseconds open wire act as inductors too before voltage is saturated as there is a temporary wire load before that . Each component is contributing its share to what ends up being seen on oscilloscope ,i wonder if heat fluctuation is causing the jolts by changing the resistance ,speed of electrons across conductors .Good presentation
The disconnected pair of wires actually seem to perform as an inductive capacitor. Storing voltage at first, then feeding it back into system. I couldn't imagine how much time you spent on this experiment. But the insight you have given your subscribers is beyond time. Very nicely done.
Hi mate, I have been involved in manufacturing electric motors my whole life. At 57, that was one of the most interesting and educational videos I've ever seen. Top work.
Hats off to that video that greatly clarifies what electron drift velocity is and why it is so much slower than the electromagnetic waves'. That also helps convincing people that circuit simulators work since they solve discretized/numeric versions of Maxwell's equations in nanosecond time steps.
This must have been a massive effort to put together but it is such a good demonstration. Thank you for creating this video!
Yes. I must've been a lot of work. The time spent on all of this could easily be lost if you haven't done or studied and reported on research.
Excellent content
As a EE, this is such an AWESOME visual demonstration and explanation of wave propagation and reflections! It gets into great logical detail without being too much for the uninitiated.
As a robotics mentor as well, I am absolutely going to use this video as a primer for my students to justify why a CAN bus should not have stubs over a certain length and exactly why those 120 ohm resistors should terminate the ends of the CAN bus to minimize reflections.
Wow. This is mind opening. You deserve all my respect. You are steps above any professor in experimental physics I met during my studies.