Finally a YouTuber that actually goes into detail with experimental setup and allows us to conduct our own independent research ❤

I love how this video demonstrates that proper experimental design relates to just careful thinking and understanding of assumptions and first principles, and does not have anything to do with how fancy the equipment is. The whole experiment used dead bug circuits and a super cheap scope, but was crafted to be able to gain them necessary insights, and it does so with sufficient resolution to prove the points.

THREE AlphaPhoenix videos in one day?! Christmas came early!

I agree the 3 videos should be a mini series or a really long video on your main channel.  Stuff this good shouldn’t be resigned to the second channel

I think every experimental research paper should have a video like this, it would make replication a lot easier

For improved accuracy with differential probes, you should have connected the grounds between them!
The second thing, and I think you did do this, but non the less:
It is very important to use the x10 setting on the probe for two reasons: to increase the input impedance of the probes (the thing you tried to do with capacitors), and to enable you to trim the probe's compensating capacitors (little screws on the side) to eliminate ringing.
Trimming is done with a probe attached to the test generator contacts just beneath the display in the middle of your scope.

The problem you saw with the probe disrupting the signal patterns is from the ground connection of the trigger probe attached to the switching circuit.
You really should have added some proper analogue switchings to the circuit, like SN74AC66, and also separate batteries for the oscillator and the driving the line, to mitigate ground coupling through the scope.

This was really cool, please make more EE content. 90% of ECE content on youtube doesnt go past first 2 weeks of Electronics 1 so its really cool to see some applied signals content.

Ah, I see you are an aficionado of 3D "just solder it on anywhere" circuit design. Applause, applause. You win 4 internets.

20:45 "And it's just that easy" is quite the statement! That is a LOT of painstaking work with many mistakes that can be made. Very impressive research and so cool that a reasonable digital oscilloscope can capture this.

The twisted pair is a transmission line. Your rapidly switched  pulse  is a mix of RF (wide band) and DC. We need to be careful and not equate the DC bulk Resistance of the twisted pair to DC flow, with the  Impedance of the twisted pair to an RF wave front.  Different critters. The pulse that is impressed and propagated at the velocity factor of the transmission line when the switch fires each time, is primarily a radio wave that rides up on the skin depth of the wire (frequency dependent) and its propagation along the wire is resisted by a combination of reactance and surface resistance, that we call impedance. Along with that is the DC current that is more controlled by resistance and propagates through the bulk of the metal at a different velocity.
This can be shown by a long balanced line made of two, very thin wall, hollow copper pipes. Measure the DC resistance of the line, then measure the impedance and velocity factor of the line at some arbitrary, but stable,  radio frequency.
Now, replace the hollow pipe with solid round bar of the same diameter and repeat the measurements.  The DC resistance change will be significant while the velocity factor of the balanced line to the pulse will remain close to the original.

Love your posting of the extra stuff and outcuts here! Thank you for all the hard work!

If you want perfect equal current on pluss and minus cable, maybe just use a small high speed transformer as your supply.

Current should be equal on both sides in my mind 😅

All 3 vudeos wefe just amazing!! Seriously!

I would make two minor changes though. For the Schmidt trigger, add a couple.of 0.1uF or even 10nF capacitors.ij parallel to the large ones you have. As close to the vcc/gnd pins of the chip as possible. Rhe big capacitors help but their internal resistance and inductance means that they are "slow". So for the very fast transients you want a fast 0.1uF capacitor bormally known as a "decoupling capacitor". This will give you much better rise times

Swcond improvement would be to use a differential probe inatead of the math function. Thia way you sont have to worry about the disconnected ground leads and the inductance that those leads (pf the red and black probes) create. Remwbwr that all ground ports of the scope are common ao you have a "back" path or at least aome potential interference from the ground leads hanging around.

A differential probe does the math in analog way nect to the measuremen point and ahould give you wven better noise immunity (although the traces did look very goos)

Finally, given you hace a "repeatable" trace.. if you apace put the pulaea enough (say at 10khz) you can use the averaging funxtion of the scope to get better dynamic range /.noise performance by accumulating hundreds of runs of the same repetaed event.  

Some scopres (sampling scopes9 can evwn increas the time resolution by adding a slight jitter to the trigger and getvsamples at slightly different times but due to the repetitive bature of the signal, tgey can build a higher resolution (time wise) "Image"


Finally ypu can use the trigger input od the svope instead of one of the channels, directly from the Schmidt trigger output (maybe uaing one of the channelse separately). That way you can sanple using channels 1 and 3 and thus run the scope at dohble the rate. For example of the scipe is 1gigasample/s that usually applies to channels 1 and 3 by themselves. But if you capture all 4 channels.or 1 and 2  (or 3 and 4) then the rate goes down to 500 megasamples per channel

To switch the Hex schmitt trigger inverters quickly you need to supply current to the IC over a large frequency band (Fourier analysis), which means you have to have instantaneous current flow at high frequencies to minimize the signal rise and fall times, meaning smaller value supply capacitors (higher self resonance) as you get closer to the IC power pins while minimizing the device lead inductance (lead length). But, you will quickly be limited by the IC package internal lead inductance. You will have several capacitors in parallel of different values and types all working together to meet the high frequency IC switching current demand. The aluminum electrolytic capacitors in the video have much too small a self resonance frequency to supply the needed current to switch the IC quickly, and the bulk capacitance is largely negated by high inductance of the long lead lengths.

Yessss! I was wondering exactly what this video answes. You're the best, dude.

As a chemE with a job that requires a lot of electrical engineering to understand, I very much appreciate this video. I can conceptualize AC to some extent with the metaphors everyone uses, but they're always too imperfect for a true working understanding. This helped me grasp what is actually going on. ESPECIALLY for Characteristic Impedance, the most insanely confusing thing I have ever tried to wrap my head around. One thing I don't really understand is why the electrons in the adjacent turn of the wire are induced to move in the opposite direction as the previous turn. I understand that the electrons will eventually be pushed in that direction, but not why the induction forces move them that direction.

When I watched the main video I thought, wow, he must've had a shitload of probes to take all these measurements at once.
It never occurred to me that you just took a shitload of measurements with three probes.

Thank you for your hard work!

AlphaPhoenix: "We take thousands of measurements so you don't have to." Mind blowing project. Amazing attention to detail. And a result that changed my understanding of electricity. I'm subscribing... and continued success!

This project is a masterpiece. Well done. Thanks for showing the setup as well, this answered all my questions, along with all the questions I didn't ask but should have

This channel is the perfect ratio of intuition, and detail