25 years ago I learned all this at university.  But the depth of insight you've added to that basic knowledge is a revelation.

As an RF Engineer, I live by this principle. It was really cool to see you approach it from the DC perspective and I am very impressed by your painstaking oscilloscope measurements!!! I have only ever seen plots like this in simulations, never with true measurements.

You can also view terminating resistor as substitute for the rest of infinite wire. This way it's easier to understand why there is no reflected wave in this case

The fact that more or less consumer grade scopes can actually capture this is utterly brilliant. And then all the graph visualisations, especially the one with the 8 or so different resistance levels and see how impedance matching magically works... very very cool! And fairly important with everything with antenna's, especially high powered ones that will reflect significantly if not correctly matched, blowing up amplifiers in the process.

As someone who has learnt this at uni, i can say these videos have been the best explanation i have ever seen

I don't often write comments, but WOW this was awesome. This, combined with the last video somehow got me to see an intense beauty in this "low-level", more advanced type of electrical properties. Thank you so much for this

It was really interesting to see the dynamical demonstrations of pulses propagating and hitting the different loads! I didn't expect the real world waveforms to be so close to the ones you see in textbooks. Bravo to you!

As someone working in testing motors for EVs, this video and the main channel one were GOLD! The Portuguese PhD who tries to educate me at work will love this, and hopefully i can understand more about EMC!

Let me tell you that this just made me make sense of the DMX line impedance loads used to avoid "reflections" in the line.... I knew about this ripples or waves of "voltage" but I couldn't figure it out why a load of an "apparent impedance" could work to "destroy" them.... This is just amazing.... Thank you.

If you use the electron motion visualization again in future, adding colour based on speed may make it a easier to see the changes in velocity, so blue is slow, red is fast, and rainbow or gradient between.

Also, this video should be required watching for every EE student, it explains and shows impendance 10x better than anything I got in school.

The link to the main channel in the video description leads to an error page, because of an ')' at the end of the link.

I've been an Amateur Radio operator since 1996 and never seen this put visually before and it was exactly what I needed to see. Thank you.

Never seen this much honesty in anything related to electricity. My heartfelt thanks and prayers to universe that every EE in the world follows you. I hate just assuming things because somebody says so with oomph and authority.  You deserve 8 million subscribers not just 8K.  Just keep it basic and honest.  This content is like watching Faraday himself at work.  So innocent and humble.

By the way, Snell's Law and impedance matching are related concepts.  Also, impedance matching has a mechanical analog - stiffness matching either with actual springs like suspension systems or through Young's modulus (material property) and geometry of the structure. Mechanical waves will reflect if stiffnesses are not match. Also, I ran a jackhammer once, and I noticed the hammer action depended on how much force I leaned into it with.  If you put too much force on the jackhammer, the hammer couldn't hammer.  If you put too little force, the hammer would just bounce off and not do anything.  Somewhere in between, you get good hammer action.  Very similar in concept to the suspension system I already mentioned. You have to carefully select the spring and damper for a vehicle's suspension or it will act like the jackhammer with the wrong force applied. The suspension will either be too soft or too hard.

As a ham radio operator and long time mechanic and experimenter you have just explained something I could not see in my mind for 50 years. Now that I have a visual, it is unbelievably simple. I was like you about the coax cable. I never could see how a 15 foot piece of 50 ohm could be the same as 200 feet. That really bugged the piss out of me. Thanks for the video.

I’ve been trying to understand this for 20 years and this video finally made it click. Thank you so much!

I think I am going to have to watch this video 150 more times so I can understand it... My learning impedance seems to also be 150!

At D.C., yes, it reaches an equilibrium quickly but the point of impedance matching is at high frequencies where peaks and dips of frequency response will occur if impedances aren't matched. I find it very interesting and enlightening seeing these high speed captures you are doing in understanding these phenomena. It makes it so much easier to see what is happening. It is distributed capacitance and inductance which creates the 150 Ohm (or whatever impedance, it depends on the cable configuration / geometry) and the distributed resistance which determines the Q (usually negligible), but the basis of why this happens is shown in the transient responses you are demonstrating. This is significant and will be appreciated by teachers in time. Please keep up the good work!

This doesn't just apply to long wire transmission lines. Changes in impedance on PCB traces or lines connected to them creates reflections and that's generally where noise comes from. Robert Feranec has a bunch of videos talking to a signal integrity expert, Eric Bogatin, and he basically explains everything you did in these videos but in the context of PCB design.

The role of impedance matching in minimizing the reflections of the electrical waves is exactly what you would expect from the role impedance matching has in minimizing reflection of acoustic waves. Think of the load as a boundary between two media through which the electrical waves travel. If the resistance of the load is higher than "expected" it will cause free-end reflection (you can see that the reflections from all loads greater than 150 ohms are not inverted from the original pulse). If the resistance of the load is lower than "expected" it will cause fixed-end reflection (the reflections from loads lower than 150 ohms are inverted from the original pulse). If the resistance is just right, it's like a transition between boundaries of identical densities, no reflection will occur.

Really cool to see this!