How Does a Tesla Coil Work? A Historical Deep Dive

[@jwingo7257]

You have a gift at combining the historical perspective with the science and make it both entertaining and educational. Love your content! Keep it up!

[@MoveMakerTV]

I completely agree!!!!

[@RichardFreeberg]

Great presentation! Thanks Kathy! I wish that such content had been available when I was growing up back in the 50 and 60's. In particular your including the historical and human drama of the development of science is sooooo important! And you're doing it while accurately presenting the science. Marvelous.

[@nigelradcliffe7613]

Wish I’d had you when doing electronics. You simplify it so much. Thank you

[@AJMjazz]

Your videos are excellent, Kathy. You provide enough theory, math, and history to make all of it logical and easy to grasp. Long time electronic tech and ham operator here, this has provided me with hours of refresher info and entertainments. Kudos!

[@peterjeffery8254]

I already know most of this but your delivery reminds me of how special it is. I was smiling the whole way through. Thank you Kathy.

[@nastynate534]

And we love Kathy! P.S.- just found your channel, but you’re stuff is exactly what I was looking for. Keep up the excellent work, ma’am. This is the level of dedication, education, presentation, etc. people truly appreciate (and yes most people don’t realize it, but keep on the grind and hopefully some comments/patrons will give you some validation in the meantime)

[@connorfisher1651]

Tesla was using impulses waveforms; not a.c; as the input to his magnifying transmitter. The torroid placed atop his tower was not used to ionize the atmosphere which only creates coronal discharge, but rather was utilized in order to reflect the uni-directional impulses into the earth. Tesla stated clearly that these impulses were pressure waves; not transverse electromagnetic waves, and by using these pressure waves he could then set up a grid across the earths surface which he could utilize to transmit electricity from his transmitter to the various resonant recivers which would be placed on above mentioned nodal points. If you understand the skin effect in relation to high voltage aplications, cymatics, and can comprehend that the interior of the earth was used as a component in his circuit then this concept will make a great deal of sense. Marconi simply ripped off teslas patents, and borrowed ideas from hertz and others in order to create a half baked form of radio that wasnt useful as a means of communication until r.c.a came around, and developed the amplifiers and vacuum tubes that actually made radio practicle and engineerable. The analogy of a tank circuit is useful in regards to analyzing the basic function of a tesla transmitter. That being said you have missed some very key components that lead to an understanding of tesla's ingenious and heavily supressed system of wirless electrical transmission.

[@David-sp7gc]

Tesla had poor math skills and did understand the inverse square law. This is why high power can’t be transmitted very far.

[@JohnBerry-q1h]

CW is also a grossly inefficient way to transmit radio signals, in that it requires a massive amount of input power, supplied to the transmitter. Instead, it is much more efficient, and consumes a helluva lot less power, if you duplicate the shape of the modulated signal (sent as input to a transmitting antenna) with a sequence of evenly spaced (in time) *momentary impulses* (...otherwise known as a *pulse train.* ) When the receiving tuning circuit "sees" the individual impulses, each impulse "smacks" the receiving tank circuit (...like a man striking the surface of a bell-tower Bell, with a hammer.)

[@mrmeaner305]

His haircut also caused some great difficulty as well 😢

[@timothystockman7533]

When I was in Jr. High, I built a Tesla coil. The primary was several turns of #14 magnet wire on an oatmeal container, andhe secondary was many turns of #22 magnet wire on a yard long cardboard tube from a fabric store. Instead of a spark gap generator, my coil was energized by continuous waves from a pair of transmitting triodes. I got a nice spark discharge from the top of the coil.

[@Kathy_Loves_Physics]

That is amazing and very brave of you

[@stevea2909]

I went through an electrical apprenticeship and I learned new things from every one of your videos, Thank you!

[@flagmichael]

There are a couple of "by the ways" in the description of operation of the Tesla coil. Unlike most air core transformers a TC has the majority of the secondary uncoupled from the primary; typically the primary is about a fifth or so the length of the secondary and is generally loosely coupled. A variation of the Tesla coil, known as an Oudin coil, is an autotransformer with the same working principles. Most of the extreme voltage rise comes from the effect we see in resonant antennas: peak currents at the feedpoint and peak voltages at the open end(s), but in Tesla coils the goal is not to radiate energy but to cause the standing waves to pump as much of the energy as possible into the end of the coil. The voltage rise is almost entirely outside the coupled section.

[@vinquinn]

Good to her you call it an Oudin coil. Most people have never heard of this and mistakenly call them all Tesla coils.

[@dahawk8574]

6:41 - A good addition would be a quick explanation why this is called a "tank circuit". In physics, there is the 'SHO', Simple Harmonic Oscillator, which can be a mass on a spring that bounces back & forth. In designing electrical circuits, water analogies are often used, and this kind of oscillation can be observed in a tank of water where the water sloshes back & forth. So a "tank circuit".

[@Kathy_Loves_Physics]

I just noticed this comment Da Hawk. I didn't know why it was called a tank circuit, that is very cool. I mention how tank circuits work in a bunch of my radio videos but never why they were called that (as you just taught me). Thanks, K

[@dahawk8574]

For everything you've taught me, I figured I owed you one! Even the math behind harmonic oscillation is fascinating. Sine waves are just circles, from a different perspective. This .gif explains it in 2 minutes: en.wikipedia.org/wiki/File:Sine_and_Cosine_fundamental_relationship_to_Circle_(and_Helix).gif I remember the day when I was sitting in class and this realization dawned on me. That was a great day.

[@Kathy_Loves_Physics]

Da Hawk I had heard that one before and agree it is super cool. As a physics gal who has never taken a EE course I just learned how tank circuits work like last year so I am waay behind on engineering. But I’m working on it.

[@dahawk8574]

As a tangent... It was about that same time for me in school when I had a class where my teacher explained to us how army tanks got to be called 'tanks'. It was a cover story for these newfangled things that they were a way to get water to the infantry troops. "Tanks of water". And this name from the cover story stuck. There's a history to absolutely everything around us. It's just that the vast majority of the stories are forgotten.

[@Kathy_Loves_Physics]

Da Hawk ok I actually gasped. I love that stuff.

[@GriffinGBrock]

Some points of interest for your consideration: 11:10 "ionization of air" Rather than employing the term free electrons to describe the discharge emanating from the capacitive torus of such a setup, it is truly the action and strain of the connecting electric field lines which in due cause a discharge in the surrounding air. Granted that the modern day Tesla Coil, one of high impedance, high loss, and little use for radio telecommunications, possesses a donut shaped top load, this gives a nonuniform potential gradient surrounding the torus. The sides of this shape pose to increase the electric field gradient and number of lines of force per square centimeter, causing the dielectric strain of the surrounding air to breakdown, as the quantity of electric lines of force increase with respect to terminal potential. Hence, a discharge occurs. For this reason, Tesla speaks of employing spherical top capacities, as a sphere provides the most uniform field line distribution, preventing stray discharges to some extent. 11:25 "Wardenclyffe to electrify the globe" Despite the lack of a functional setup in the end at Long Island, it is to say without doubt in retrospect, that Tesla seemed to be mainly concerned with toying with experimentation, rather than simply constructing a functional setup. After returning from Colorado Springs, where a respectful amount of data was collected on the effective transmission of telluric communication, something seemed to have went askew, as his latter patent on Wardenclyffe would stray away from an efficient coil setup. His three coil magnifying transmitter arrangement developed at Colorado Springs had maximized transmission efficiency, by constraint coil geometry of stout form. The opposite of which is seen in the Wardenclyffe patent. For this reason, many believe that the modern day Tesla Coil of elongated proportions is in fact the finalized and perfected transmission apparatus which Tesla had developed. The latter of which is falsehood, whereby Colorado Springs appears to be the correct avenue of conducted research to approach.

[@zachreyhelmberger894]

Another way to explain the Leyden jar and coil circuit (aka a tank circuit) is to think in terms of energy storage. Electrical energy in the form of an electric field is present in the fully charged capacitor. When a coil with a large number of turns is connected to the capacitor, one would expect an instantaneous large blast of current and a spark like with a short piece of wire. But what actually happens is that the current rises in the coil much more slowly because of Faraday's law of induction. As the electrical energy of the capacitor is being transferred to the magnetic field of the coil, a "back EMF" is induced in the coil that opposes the change in coil current. Thus the coils slows down the transfer of electrostatic energy to magnetic energy. At some point the coil current reaches a maximum and and then the magnetic field starts to collapse inducing a coil voltage in the opposite direction and charging the capacitor back up again but in the opposite direction. Once the magnetic energy in the coil is fully discharged into the capacitor's electric field, the current starts flowing in the opposite direction as the capacitor discharges itself back into the inductor again. Finally, the after coil has charged up with magnetic energy and discharged it again to the capacitor, the capacitor is back to it's original polarity and voltage sans a certain amount of energy lost to electromagnetic field emission and heat due to resistance and other losses.

[@MrElapid]

Correct!

[@zachreyhelmberger894]

It is important to note in the Tesla coil schematic shown in the video that ONLY the capacitor and the primary coil of the air-core "Tesla coil" is involved in generating radio frequency, RF, energy that excites the RF secondary of the Tesla coil. The only job of the secondary of the iron-core transformer is to charge up the capacitor to a voltage high enough to jump the spark gap which then discharges the electrostatic energy in the capacitor into the few turns of very heavy wire of the primary coil to create a very intense magnetic pulse which then charges the capacitor back up with the opposite polarity as the magnetic field collapses back into the primary of the Tesla coil, etc. The "size" of the capacitor and the "size" of the inductor determine the frequency of the sinusoidal oscillating current in the tank circuit.

[@larryniidji]

Marconi not only use Tesla technology but Tesla also used radio to control his submarine 11 years before Marconi's transmission.

[@colekeircom]

Thank you Kathy. Very well explained in a concise and no nonsense manner . Anybody who feels they need more detailed information can use this as a starting point . Regards Kieron

[@Kathy_Loves_Physics]

So glad you liked it Kieron feel free to share

[@kennethfuller3618]

I have read and watched several explanations of the Tesla Coil and, until this video, walked away just as ignorant of its workings as I was before. This video has to best explanation ever .

[@scfrhc9131]

Your discussion is very interesting and intense but I’m afraid that I will have to listen to it many many more times and probably transcribe it before I can even understand it enough to ask you a sensible question…notwithstanding thanks!

[@kamatchinmay]

Why didn't KZbin recommend this channel sooner. The content here is amazing

[@ryandodson919]

Thank you for making this. Its very well put together and clearly explains Tesla Coils and the science behind them. I use this video for training volunteers at the science museum I work at for our Tesla Coil shows.

[@Kathy_Loves_Physics]

That makes me so happy.

[@Simonjose7258]

I Freaking Love this Channel!

[@Kathy_Loves_Physics]

Simon, I am thoroughly enjoying watching all your comments as you binge watch my videos. Glad you like them and thanks for commenting so much.

[@shelliecarlson7015]

It's because of Kathy's enthusiasm. She, obviously loves electricity, and it becomes infectious. If I had Kathy as a teacher, I would have paid attention instead of learning it later in life.

[@robertakerman3570]

@@Kathy_Loves_Physics A friend Did make a T.Coil(cool). I owned several cars that ran on both "interruptors & excitors". Lastly; I'm not sure if "back then" it may have been the shape of the coil, but in modern times physical shape /size doesn't matter. Time is wonderful (usually).

[@Darthvanger]

The best explanation ever, I understood it! :) Simply combining a few experimental results \ machines we end up with this scheme and it even seems simple enough. Everyone is trying to explain it with the theory and the laws, only to make it more complicated to comprehend. Kathy one love ❤ You're making physics great again!

[@Sunspot1225.]

Physics class in college would have been almost redundant except for the mathematics involved. I understand your presentation and it is enjoyable. I have a playlist with all of your shows.

[@dewiz9596]

Delightfully educational. Presentations like this make me realize I’m still not too old to learn!

[@michaelfoster8929]

What an amazing presentation / video - well done

[@martinhaub2602]

This is the best, clearest explanation of how a Tesla Coil works I've ever seen! Thanks for doing it.

[@car9167]

not really...

[@PinkeySuavo]

I came across on one of your videos before but I didn't open it. Now I did and I don't regret. Interesting history! I saw a 3-hours documentary about history of electricity but clearly it missed a lot of points, and this video filled a lot of gaps out there. Thanks!

[@Kathy_Loves_Physics]

Welcome aboard!

[@ronaldhenderson8660]

I join those who love your info and delivery. Thank you

[@therongertz3570]

Excellent videos! Just found you recently, and have loved everything so far

[@dougdoug2165]

Great one, again. Tying up the loose ends in the understanding of electricity. The historical perspective really cements the tying up process. Thank you, wish you would have been around 40 years ago. Kids: pay attention to this.

[@peterbonucci9661]

This is the best description of how a Tesla coil works that I have seen. Thanks.

[@aminnima6145]

I can't have enough of your awesome videos

[@paulmiles1065]

One of my all time favorite channels!

[@jamesslick4790]

I just discovered your channel, And YOU and "Technology Connections" make learning about the ROOTS of tech SO damn FUN and EDUCATIONAL. I have been into ANYTHING electrical (and mechanical) since I was a kid in the 1970s, And even if there is stuff that I knew, both of your channels brought the "deep dive" I have wanted FOREVER. I am NOT a "fan" of a lot of what KZbin does (to content creators...or viewers) BUT, The access for "regular folk" to a (let's face it..) television platform make me glad that "cable" is dying. I never EVER got the likes of this even on the (over hyped) vaunted PBS. This RIGHT HERE is "Educational TV" as it SHOULD BE. 👍😊👍 PS watching on a PC connected to a projector to a 120" screen. WE LIVE IN THE FUTURE!

[@susilgunaratne4267]

Beautifully presented as usual with energetically & convincingly.

[@h-h1859]

Thanks for the video.super interesting and informative. Im always facinated by history of science and humble beginings .🙏❤️

[@huangchao5164]

exellent description of old stories, the principles of devices are so nature and clear for understanding! thanks!

[@Kathy_Loves_Physics]

Glad you liked it and even more glad that it made sense to you.

[@tgs2012]

Great presentation Kathy! Thank you.

[@Kathy_Loves_Physics]

Glad you enjoyed it!

[@gabrielhacecosas]

What an excellent explanation. I've recently discovered your channel and I think it's great. 11:04 It is better to put the spark gap in parallel with the transformer and the capacitor in series with the primary coil. As you have it in the video, you run the risk of the high frequency getting into the transformer and burning it out.

[@MrDuran9000]

WOW, I think your great. Made people think! Quick and to the point. Wish you great success and thanks for sharing knowledge.

[@Kathy_Loves_Physics]

MrDuran9000 glad you liked it. Feel free to share with friends and enemies 😉

[@cosmicHalArizona]

So clearly explained. Was able to follow without mind overload & brain shut down. So well done!

[@Kathy_Loves_Physics]

So glad

[@rolandmousaa3110]

Thanks for the SC ED.. Keep up the Good Work! (inventor)

[@seeker4430]

Absolutely love the content.... Beautiful... More power to you

[@twistedyogert]

4:23 They were also called "trembler coils". Early cars used these devices to fire the spark plugs.

[@Kathy_Loves_Physics]

I knew that they are used in spark plugs but I didn't know that they are called "trembler coils" what a cool name!

[@WJV9]

The vacuum tube radios in automobiles used vibrator coils to produce high plate voltage for vacuum tubes from the 12 volt DC battery. You could always hear a hum of the vibrator when you turned on the radio.

[@robertmoskowitz3101]

In Jr. High, our 9th grade science teacher had a monster Tesla coil. Primary was 5 turns of 1/2" copper tubing. Secondary was 5,000 turns of #10 copper wire. This was hooked up to an oil capacitor bank able to put out 10KV. Yes, a 10MV spark, but a very low current. I walked up to it, put my hand into it... Fun!

[@ollieoniel]

if you use resonance. If you run the circuit through a differential equation. There is a thing where the oscillation causes the wave to get bigger and bigger with just the right input frequency. This is an extra design feature tesla intended to use the coil to create massive changing voltage fields.

[@2Steps2D]

Great and interesting content. Keep it up!

[@tiagoperes1631]

I found that one!!! Hahaha 🤣 I’m in love with your content!!!! 🥰 Thank you again!!

[@zubershaikh7663]

I like you video and i always interested in how things firstly happened.. thanks for ur video.

[@laskartrece]

Some people love you. You induce affection don't know how...? thank you... You give science a heart and a purpose.

[@finallyy3959]

Mam Iam from India. I really loved u r exploitation

[@Kathy_Loves_Physics]

ananthula shiva so glad you liked it. Hope my California accent wasn’t too difficult to understand. Cheers

[@paknbagn9917]

really good video and explained easily

[@tanner1985]

I appreciated the fact that every time a name was to be given, it wasn't the name I supposed :D Oersted, Ruhmkorff... neither one I guessed right! Thanks to this I have info to search more and again, to have a better picture. Thanks! The downside of this videos is, despite being well informative, it failed to point out HOW the high voltage in the topload is reached. It is *NOT* just by induction. It's because of the loose coupling between the primary over the secondary, the secondary itself being a single wire transmission line with a lenght sufficient to sport transmission line properties, and resonant rise in the 1/4 wavelenght... The question "How does a Tesla coil Work" can't be answered without the loose coupling, dear physicist.

[@BBQDad463]

Thank you for this video and for all your videos. Keep on rockin'! It has always been my belief that the letter to be transmitted by Marconi was "S," and that the letter as well as the date and time of transmission had been predetermined and agreed upon by Marconi and his assistant in America. So... "I plan to transmit the letter "S" at a precise date and time." "I will be ready and will watch closely at the precise date and time, oh man who signs my paycheck." "Did you receive the letter "S" at the preordained date and time?" "Yes, I did, exactly as you said I should, at the precise date and time, oh man who signs my paycheck." Or does the historical record truly say otherwise?

[@JohnBerry-q1h]

So, a Tesla Coil is sort of like a klystron, in that the output frequency of a klystron is much higher than the supplied input frequency, while simultaneously creating a voltage gain on the output frequency (whereas a magnetron only amplifies frequency, without creating any voltage gain.)

[@MaleAdaptor]

Excellent video but @11:30, you do not have Tesla's vision. Other's think differently search fo "zenneck surface wave" and corrolate that with Warden Clyff.

[@sayedhassanphysics8491]

Great and interesting content. Keep it up ❤️👍 Beautiful video Thank you .......

[@danielmusat597]

Hi Cathy! Just a small correction: capacitors do not store energy in the plates (as most electrical engineers will tell you) but in the dielectric between the plates (be it material or vacuum).

[@zachreyhelmberger894]

It is kind of both, I think. The positive plate will have a deficiency of electrons and the negative plate will have an excess of electrons. These net charges create an electric field that is the most intense between the plates. The dielectric in between the plates can reduce the intensity of the electric field in between the plates by electrostatic induction in the atoms or molecules of the dielectric. The greater the dielectric constant, the lower the intensity of the electric field (or voltage per unit distance) for a given differential of charge between the positive and negative plate. This allows more charge to be transferred from one plate to the other before the voltage gets too high and dielectric breaks down and a spark ensues or the charge finds another route from one plate to the other typically in a rather dramatic fashion. Similarly, a conductor with and electric current passing through it creates a magnetic field, which is also a form of energy storage. When the current stops, the magnetic field "collapses" into the conductor and causes the current to flow in the opposite direction.

[@pixelking8706]

This'll be great for my project! 😃😁

[@Scriptank]

This as absolutely awesome and so informative! Thank you.

[@wisdomovermoney3394]

That intro is dope

[@climbeverest]

Please also do 30 minutes or more, you have such talent and such deep knowledge, we want to know history of physics, especially voltaire’s girlfriend, I forget the name was incredible engrossing

[@Darthvanger]

Can you do a video on why magnetism is a relativistic effect of electricity, and how it all works? And with history of discovery ofc :)

[@braaitongs]

What about the importance of the spark gap? Ie disruptive discharge? And also what about the radiant energy produced by his tesla resonant transformer?

[@futureboy7653]

@ 3:45 : "CATARRH" Now that's an ailment

[@margidim1472]

It will be very interesting to learn about the history of semiconductor and full conductor's electricals or electronics 🙂

[@debeshbhattarai]

Love it, Tried making one...looks a bit difficult feat though. Keep inspiring.

[@zachreyhelmberger894]

Let me know what you are doing. I have built a number of Tesla coils in the past. I might be able to walk you through the construction process.

[@debeshbhattarai]

@@zachreyhelmberger894 Most of the videos in KZbin seems to be baseless, it rarely works. I am more intersted to get it simple by having limited electronics here...say merely by controlling turns in Primary and secondary. And may be basic assembly for on off switch in a very primitive way...as they used to do 150 years back...MORE LIKE A BARE SCIENCE...!!

[@debeshbhattarai]

May be you shall add a line or post the details in video soon. I got make one DIY Tesla soon. Cheers Mate. Also a line about me for your Info, myself an architect, musician, DIY enthusiast and Exercise Guru. Cheers...!!

[@billsmith8853]

One thing that is often overlooked about Tesla coils is that as well as being a step up transformer, the secondary is ideally also a 1/4 wave transmission line at the resonant frequency of the primary tank circuit.

[@tobystewart4403]

What is a "1/4 wave transmission line"?

[@billsmith8853]

@@tobystewart4403 There is plenty of info about transmission lines on You tube and other places.

[@mikepasko7493]

Great explanation

[@eloycastillo4191]

Can you talk about darzoval currents....and how make scalar phenomenon?

[@frostfamily5321]

I hope you get to make a video about laser keyboards and the science behind them!

[@chainsik3817]

Buen video, me hará salvar el semestre!

[@pramitchaudhury1821]

In love with your content ❤️❤️

[@lordbeebus9842]

Great work!

[@sunnyray7819]

Very interesting, I never knew about the tank circuit. I heard about it a while back but forgot to be honest.. I just kinda know enough to be dangerous.. But, now I understand how the Telsa coil really works. Thanks for the great explanation!

[@PuwadejP]

Thank you so much for your great work.

[@Kathy_Loves_Physics]

You are quite welcome.

[@LadyAnuB]

The disconnecting switch @ 4:07 is the same principle used in tattoo guns but the switch is extended and connected to a tattooing needle. So now I know Fizau created the LC oscillator.

[@vinquinn]

I understand ideally that the secondary coil should be one quarter the wavelength of the operating frequency.

[@OnlyTheParanoidSurvive444]

This was great!

[@coffeeisgood102]

If I keep watching your channel I’m going to have to get a bigger brain to store all this knowledge.

[@MartinKellerII]

Don’t forget to mention that Tesla was fiddling with radio transmission before Marconi (and so were others). Marconi just (only marginally) improved it and had a better marketing.

[@neko7787]

Thx for the clear explanation... 💚

[@cogentdynamics]

What a great presentation!

[@Kathy_Loves_Physics]

Glad you liked it!

[@dirkpitt5468]

Awesome sauce!

[@binsojoy90]

nice job

[@climbeverest]

Madam you know so much, I want to get back to vector calculus and start learning physics like I am in Newton’s time do you have book recco for this?

[@gregorycotter6461]

Great video.

[@diplomatutorial3256]

really this video was very enlightening for me

[@Kathy_Loves_Physics]

I am so glad. Really, it makes me smile to read positive comments and helps me through the mean and nasty ones.

[@hank1519]

Beautiful video! Thank you!

[@redminote5pro399]

Subscribed 👍

[@mahoneytechnologies657]

Perhaps you should look at the Radio Controlled Submarine that Tesla Demonstrated using radio transmission, Marconi's patent was overturned in favor of Tesla. Tesla was big on using Resonant LC Circuits and Mechanical Resonance. Your videos are a Breath of Fresh Air and it would be great if they were referenced in our grade and high schools. The sooner the better, young kids should be exposed as early as possible to Science and Mathematics, fresh young minds are willing and able to absorb such material, learning should not just be given in a linear input procession of information, e.g., As quickly as possible a Map of the mathematical Universe should be presented, a road map of the possible paths in the future math journey. Fresh Young minds are wide receivers of information! When I was young I liked to hang around with older kids and listen to grown-ups discuss things, they knew more. My father had a saying, The Walls Have Ears! Referring to me.

[@notapplicable2515]

Watching this, seems to me the University has moved from buildings to KZbin. I would know, I work at one.

[@dougdoug2165]

I think you need a spot on Saturday morning tv. They should get you on with Mo Rocca's Innovation Nation.

[@Kathy_Loves_Physics]

Sold!

[@boone7777777777]

I love this video, makes me want to try to build a tesla coil

[@mostafaismail43]

Amazing video

[@Kathy_Loves_Physics]

Thanks

[@racookster]

Very nicely explained!

[@briangenge2649]

Excellent - lucid and scintillating!

[@Kathy_Loves_Physics]

Brian Genge so glad you liked it

[@darkobul1]

Tesla said that he was able to electrify and store energy in air so much that he was able for hours to discharge a tube all around the lab even if all was shut off. Quite a different effect then what we call today tesla coil.

[@hubercats]

Another excellent video!

[@accessiblenow]

Another good one