" UNDERSTANDING ELECTRONICS: VACUUM TUBES " 1970 EDUCATIONAL FILM DIODES & TRIODES XD72594

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“Understanding Electronics: Vacuum Tubes” is a color, educational film from 1970. Presented by Universal Education and Visual Arts in collaboration with educators from both the Toronto and Scarborough Boards of Education, this film educates its audience on the history, makes and models, and applications of vacuum tubes/ electron tubes. The vacuum tube is a device that controls electric current flow in a high vacuum between electrodes to which an electric potential difference has been applied.
Illustration Thomas Edison’s lightbulb (0:29). Filament (wire) in center of lightbulb (0:41). Animation “Edison Effect”/ Thermionic Emission (1:02). Animation continues: explanation of how Ambrose Fleming expanded on Edison’s findings (1:19). Close-up “cats whisker” crystal detector used in radios (1:33). Close-up electron tube, replaced cats whisker (1:35). Diagram Lee de Forest’s 1906 three-element "Audion" triode vacuum tube (1:47). Close-up vacuum tube in lightbulb (2:24). Deconstructing parts of bulb: close-up cathode, pencil guides sight line (2:34). Anode: metal plate that collects the electrons (2:47). Anode and cathode inside glass cylinder (envelope) (2:53). Close-up of diode - tube with two electrodes (2:56). Diagram of electron flow based on charge of cathode (3:09). Two tubes with filament with addition of grid of fine parallel wires (3:28). Diagram triode electron tube (3:36). Close-up screen grid added to triode (4:07). Diagram tetrode - tube with four electrodes (4:22). Diagram of suppressor grip (4:34). Diagram pentode (4:44). Close-up black pentode tube - commonly used on radio and TV sets (4:50). Pentode in RF stage as voltage amplifier, on silver circuit grid (4:53). Pentode in power output stage as power amplifier (5:03). Examples various electron tubes on display table (5:12). Diagrams basic components of electron tube: anode, cathode, grids (5:16). Cathode turns red with head on metal plate (5:31). Cathode laying on red background coated in white substance (5:43). Wire mesh grids (5:51). Tubes in manufacturing stage: close-up hands using tweezers to place anodes, insulated with mica (5:58). Rows of completed electron tubes upside down on storage tray (6:20). Diagram how to identify tubes and their components in diagrams (6:23). Example of diagram in tube manual indicating how to identify each pin (7:07). Example circuit diagram from tube manual (7:16). Examples pulses of direct current read on oscilloscope after alternating voltage fed to diode tube circuit (7:33). Diode vacuum tube connected to red and black cables - explanation and visual of pulsating direct current (8:04). Two vacuum tube diodes set up side by side, attached to center-tap transformer (8:31). Oscilloscope screen of electrical currents - comparison between input and output voltage (9:31). Close-up of twin diode without vacuum tube (9:46). Close-up triode tubes laying side by side (10:00). Illustrated symbol for triode (10:04). Triode used as amplifier in experiment: scientist studies illustration of electrical grid set-up (grid bias voltage) (10:22). Incoming signal on oscilloscope (11:33). Close-up power amplifying tube (11:55). Power amplifier circuit - triode, input signal, power source, heater, output transformer (12:28). Incoming signal on oscilloscope (12:48). How to amplify the complete signal: circuit with addition of second amplifier tube, close-up of input transformer with center tap on secondary winding; center tap output transformer (13:10). Diagram of how circuit amplifies complete signal (13:25). Depiction of feed on oscilloscope (14:16). Various multiple electrode tubes lay spread on table (14:26). Diagram hexode tube (14:33). Diagram heptode tube (14:42). Diagram of Superheterodyne receiver - explanation how RF converted to IF (15:17). Comparative diagrams two types frequency changing circuits (15:40). Close-up twin triode used as amplifier in television channel selector (16:22). Electronic measuring instruments that use electron tube: Geiger Counter (16:39). Screen of complex radiation counter (16:50). Oscilloscope (16:53). Face of control and storage unit (16:57). Electron tube used in manufacturing: Close-up thermostat (17:01). Large industrial machine with programmed timing (17:14). Smoke detector (17:26). Electron microscope (17:51). Room filled with small/ medium-size machines that use electron tubes (17:58).
This film is part of the Periscope Film LLC archive, one of the largest historic military, transportation, and aviation stock footage collections in the USA. Entirely film backed, this material is available for licensing in 24p HD, 2k and 4k. For more information visit www.PeriscopeFilm.com

[@Gannett2011]

I grew up in the 80s collecting obsolete electronics. Valve (tube) radios, tape recorders, amplifiers. I just love that smell of dust on hot valves in wooden cases. Not even the modern 'boutique' valve amplifiers smell like that! It's funny how back then tubes/valves were old hat, and people couldn't give the stuff away. Now it's getting harder to find tubes to restore stuff. This is a great film, explaining valve technology.

[@PeriscopeFilm]

Very cool! Glad you liked it. We keep thinking it would be fun to buy a Nixie Tube Clock ... it's tempting...

[@videolabguy]

There are literally billions of electron tubes still in existence. They are still being manufactured in large numbers in the Baltic nations in the European region. Don't let anyone tell you that a particular tube is unobtainable. That is bunk. With the exception of rare specialties tubes, any common consumer product tubes are readily available. What the sellers charge for them is a topic for another day. I believe they are ridiculously overpriced based upon their abundance and the common myth you quoted.

[@fujifrontier]

You’re so lucky 😪

[@DeezNutz-ce5se]

I'd love to see your collection

[@realryder2626]

​@videolabguy I have found the best replacement valves still easily obtained for Audio are new old stock Russian made from the 60s and 70s, there is a lot of odd stuff left over from space/aircraft industry also.

[@mshotz1]

My Dad was a radio mechanic in WWII, so he was always fixing someone's TV set in our neighborhood. I remember going with him to the drug store so he could use the Tube Tester.

[@scooterp7009]

This sounds like the stuff my father used to tell me while I was watching him fix TV’s in the ‘60’s & ‘70’s.

[@Minong_Manitou_Mishepeshu]

Did he ever mess around and invent his own tubes? Wonder what would happen if red pressurized mercury surrounding a ceramic filament at 0 deg. K would do?

[@peterparker9286]

​@@Minong_Manitou_Mishepeshukelvin is same as Celcius. Highly pressurized Mercury sulpher in a centrifuge with copper disks one below one above spinning opposite directions.

[@littleshopofelectrons4014]

@@peterparker9286 A kelvin degree is the same temperature difference as a celsius degree but there is an offset of 273.15 degrees between them. 0 degrees celsius = 273.15 degrees kelvin.

[@clarencegreen3071]

This is the first electronics I learned circa 1960. Wrote a textbook on AM and FM receivers around 1975 when vacuum tube receivers were still prevalent. I've seen a lot of changes over the many, many years! It was great, but now I've been left behind. I don't like computers and smart-assed phones much at all. Thanks for posting this great video!

[@robdom91]

I was born in 1987. I've been using computers since I was 5. The first computer I ever used was the Atari 800XL which was a purely text based operating system. I was always curious about technology and I'd like to think our family was never pinching pennies when it came to buying new computers. But with the rapid rise of this new internet culture, even I'm feeling left behind. I don't like smart phones either. They're a money scam and have completely wrestled control away from the user.

[@rolandlemmers6462]

What is the title of the book you wrote?

[@fujifrontier]

Yes which book, I want to read it

[@trieck]

smart-assed phones

[@clarencegreen3071]

@@rolandlemmers6462 Book: Theory and Servicing of AM, FM, and FM Stereo Receivers. Green and Bourque, Prentice Hall, 1980. My posts keep disappearing. Sorry. This is my fifth try.

[@j.j.hunsecker3009]

This narrator is the best. The voice of knowledge during my youth.

[@makeracistsafraidagain]

I took four years of college electronics in the 1970s. All of it tubes. I love tubes.

[@Minong_Manitou_Mishepeshu]

Trump 2024

[@mickeymomighty5660]

Tube music amplifiers are still produced because of the much higher quality tone than transistor ones. They are very expensive, but die-hard audiophiles still buy them. On this day in 1967, Pink Floyd released their first single.

[@paulsherriffs]

@@Minong_Manitou_Mishepeshu I don't think he'll get a sentence that long but okay

[@littleshopofelectrons4014]

@@Minong_Manitou_Mishepeshu Does everything have to be about politics?

[@Minong_Manitou_Mishepeshu]

@@paulsherriffs Sentence for what, hurting your feelings with truth?

[@mikeray1544]

My Dad was a Navy Electrician, back in the 80's lightning damaged our Sony Trinitron T.V., he diagnosed the board(with a Simpson 260 analog multimeter), sent me & Mon to radio shack for a capacitor, he installed new part & wala- operating set...that's still hot shit to me anyway.

[@fujifrontier]

This is the way to do it ❤️ too bad these days it’s all SOC bs that is completely useless if the one chip in there flips a bit or two and dies

[@QuantumRift]

I was a 33, electronic warfare tech, in the US Army the mid 80's. I had electronics school at Ft. Devens MA for a year and we got all this tube theory - because we were still repairing TUBE equipment in a lot of intances....loved it! The R390 was a BEASTS of a radio. '

[@martinhittle]

I was a 05H and trained on these ( Ft. Devens) and " BEASTS of a radio" describes these perfectly. Or anchor.

[@QuantumRift]

@@martinhittle I remember when they brought one in that had been shot full of holes in Grenada, and...it still worked! SHOT UP bullet holes busted tubes....crazy

[@martinhittle]

@@QuantumRift I'd like to have seen that one!

[@ClausB252]

My parents had an old Telefunken console radio with phonograph. When I was a teenager it failed but I didn't know anything about tube theory so I pulled all the tubes and tested them at the local supermarket. After replacing a couple failed ones, the set worked again!

[@brettrobbins2446]

I'm 32 and I'm so glad this was posted

[@ChiefBridgeFuser]

Graduated college in 1988. Nothing about tubes was ever covered. This was helpful. Hexode is freeky: osc and mixer in one!

[@bobweiss8682]

In that application, a common name for the hexode was "pentagrid converter".

[@hmbpnz]

This is a very concise and clear explanation. Great film. Thanks for posting this!

[@lbochtler]

17:44 This Electron Microscope, model Siemens Elmiskop I, is not actually on in this shot. Its vacuum system is running, as can be seen by the pirani gauge indicator at the left bottom of the frame. However, what should also be on, or rather illuminated, is the green HV system standby indicator located at the top left of the frame, the top bulb is illuminated when the high voltage system is off, the bottom red bulb illuminates when the high voltage is switched on. interesting notes on the microscope seen here, it is configured for high magnification material science work, though could also be used for biological work. The main things pointing to it being used for material science work is the presence of the specimen tilt and rotation accessory (the horizontal cylinder just above the users hand) as well as the specimen chamber decontamination device, or rather its LN2 Dewar which the user is holding.

[@deepbludude4697]

I went to work for RCA on the test range 1981 fully charged up on transistor theory thanks to night school AS degree, get down range and most of the stuff I worked on was VTs still dug it anyway.

[@dickJohnsonpeter]

"Range"? I don't understand why you're saying they had electronics outside. I don't understand why they had a range.

[@iskandertime747]

great groovy theme! the end credits suggest that this is a Canadian film.

[@iskandertime747]

@@TFT-bp8zk it's a pretty strong hint.

[@ChiefBridgeFuser]

And somewhere in there i heard the accent--"prooocess". Confirmed by the credits.😆

[@stephenkandilotis7813]

Nice learning history and its really good that is posted on KZbin. Few factories still manufacture them particularly the audio ones. Yes I do like vacuum tubes.

[@coffeeisgood102]

Thanks for that bit of history. My 1940’s waterfall radio has many of the tubes described in this video.

[@johnbolt665]

I remember the days when your TV went on the fritz you could take the tubes down to the drugstore and check them on the tube testing machine and buy a new one if needed

[@artillerest43rdva7]

the unique properties of the tube is it is not effected by radiation, not sure if it is also not effected by E.M.P. but neat video explaining how they work.

[@littleshopofelectrons4014]

Tubes aren't totally obsolete. They are still use in such things as radio/TV transmitters, X-Ray machines, microwave ovens, and large electric furnaces. Anywhere where high voltage and high power is required. Transistors aren't yet able to operate in that realm.

[@artillerest43rdva7]

when I was a kid, there was a tube testing machine in the pharmacy that we went to every sunday. I was wonering how it worked, and how it determined which were good verses bad tubes. it even had a bunch of different tubes in numerical order on the tester. things from the past that we remember is crazy. have a great one.

[@MichaelSmith-rn1qw]

@@littleshopofelectrons4014 Don't forget about guitar amplifiers! I have a growing collection of Fender Tube amps from the 1960's and 1970's and thanks to KZbin have learned to do basic servicing of them (change electrolytic capacitors, measure resistors, set output tube bias, etc.). And current production tube amps are still being sold, although most are now PCB design, which makes it harder to work on compared to eyelet or turret boards.

[@slowneutron6163]

Vacuum tubes silence the voices in my head. When used in conjunction with EST.

[@geoffcrisp7225]

I learnt about valve technology at college but never used it because transistors were being used it the mid 1960's Elliott Automation UK computer systems I was an engineer on. Redundant technology apart from in a valve amp.

[@65gtotrips]

I’m not positive (get it ?) but I’ve heard of stereo aficionados who swear by tubes for power and output.

[@swinginsamdesigns]

Indeed they (I) do and there is a very specific reason. While transistors are smaller and more efficient, the tube has a specific property that differs from the transistor and makes it much more desirable for music. If you imagine an x/y graph of input level (y) and distortion (x), the transistor and the diode distort at a very similar rate. But the transistor creates even multiple harmonic distortions (2nd, 4th, 6th, etc. harmonic frequencies) whereas the tube creates odd harmonic distortions (3rd, 5th, 7ths, etc.). The odd harmonics are more natural to the ear (you’ve heard of thirds, fifths, and sevenths in music) and are the types of distortions created by, for example, wind rushing through leaves in a forest or water running in a river. Even harmonics are more dissonant and sound thin or metallic to our ears. Fun fact (that you didn’t ask for): this is also why the first CDs sounded thin, tinney, or harsh. The first “digital” sound was riddled with even harmonic distortions.

[@jacksons1010]

@@swinginsamdesigns No, this is one of those things that started out with facts and got distorted as people attempted to repeat the information. The difference is not odd vs even harmonics, it’s simply rooted in the typical design of amplifiers. A tube amplifier is a single ended circuit that generates a full range of harmonics - 2nd, 3rd, 4th…all of them. A transistor-based amp is usually designed for pure replication of the signal, in particular suppressing the artificial 2nd harmonic. The effect becomes more apparent when you push an amp to it’s limits - a tube amp will pump out more of those harmonics, even up to audible 5ths, making the “brassy” sound people seem to like. Solid state amps will seem to clip the sound, omitting the 2nd harmonic (by design!) which sounds “off” as the 3rd harmonic becomes audible.

[@lordphullautosear]

MacIntosh amplifiers!

[@swinginsamdesigns]

@@jacksons1010 I’ll have to revisit the paper put out by Walter Sear (of Sear Sound, NYC, RIP). Perhaps my understanding of his conclusions and the frequency analysis data is skewed.

[@littleshopofelectrons4014]

@@jacksons1010 Its ironic that most audiofiles claim that they want the highest fidelity sound possible; in other words completely linear amplification which is not actually possible with real-world devices. But the sound that they claim to like best is the particular non-linear distortion that tubes provide. They may like the sound better but the actual fidelity is inferior to that of transistors because transistors have a more linear operational curve.

[@peatmoss4415]

I wondered why the King's subjects referred to tubes as valves, now I know !

[@Minong_Manitou_Mishepeshu]

Choobs, means "tubes" in Australian.

[@ZilogBob]

@@TFT-bp8zk Of course, everything is racist now. Lee De Forest, Edwin Armstrong and Thomas Edison were white so electron tubes are inherently racist.

[@Minong_Manitou_Mishepeshu]

@@TFT-bp8zk ...no it's not. "Choobs rule" is though!

[@DK640OBrianYT]

@@TFT-bp8zk Bloody Ape. If you wanna see pure rage and racism, then stand in front of a mirror. Look at a picture of a conservative Trump-supporter. Then look at the mirro once again. There you have it, Imbicile fool.

[@firebirdco5563]

In the beginning of this video, it should be corrected to state that Joseph Swan invented the light bulb first (1878.) Then, Edison found out about it and had his team of engineers research and improve it.(1879) Later they merged and became the Edison and Swan united electric and light Co. (Ediswan)

[@lordphullautosear]

Rather ironic that, a few years before this film was made, transistors were appearing in little pocket radios that were very affordable.

[@lordphullautosear]

@@TFT-bp8zk-- you want to enlighten us, professor?

[@jamesslick4790]

You probably use a vacuum tube device DAILY and not even realize it. (hint: it's in your kitchen)

[@gordonwelcher9598]

The first transistor radio, the Regency TR-1 was released in 1954. Shortly thereafter most portable radios used transistors. It took longer for other products to use transistors. TelevisIon took until the early 70s. In 1970 transistors were used in many devices. By 1980 tubes were not used very often. Transistors took over in less than 20 years.

[@Christopherurich33]

This can make time travel

[@bsanchez3563]

Why is is cut off at 1:08 ?

[@vittoriobacchiega9118]

The fashion of thermoelectronic emission.

[@vittoriobacchiega9118]

@@TFT-bp8zk Are the charge carrier iones?

[@lwilton]

@@vittoriobacchiega9118 I think you mean "ions". No. the charge carriers are just electrons in most tubes. You need a gas to ionize to get ions, and very, very few tubes were designed with gas in them. Usually a "gassy" tube was one that had failed. (There were gas filled and mercury vapor tubes, but unless you worked in very heavy industry you wouldn't probably never come across one.)

[@vittoriobacchiega9118]

@@lwilton I'm an electronic engineer and I use vacuum tube to design amplifiers for my personal hobby. II didn'n know why are named termo*ionic* but the ions remain into metallic structure into the cathode brcause lacks electrons by 1st emissions ( thermal energy free the external orbital from atoms). Intto majority of vacuum tube is inserted the gettar to adsirb the gasses create from first initial warm up into production phase.

[@lwilton]

@@vittoriobacchiega9118 Yes there are ionized elements in the cathode. But the _carriers_ are the things floating from cathode to plate, and those are just electrons in a properly functioning vacuum tube.

[@thecatdaddy1974]

Dang Im still lost lol, that is over my head.

[@KarldorisLambley]

that colour is mad. so pink. is it for the same reason lots of old footage has the same problem?

[@DeezNutz-ce5se]

Casually pointing to electrical junctions with a graphite pencil 😅

[@tomstrum6259]

James A Fleming worked as an Engineering Consultant for the London-Edison Telephone & Electric Light Company & Certainty had easy inside "Access" to the "Edison Effect" dual element glass envelope vacuum device company notes....Ex Edison employee "Discovers" the light bulb tube....How convenient & Not an Independent discovery invention !!

[@KevinMartin44128]

Do these have anything to do with an L.E.D.

[@76629online]

Totally tubular.

[@300poundbassman]

Sounds like my father's voice telling me this when I was a boy

[@mikestuckinthe70s]

what year is tbhis from?

[@joshuagibson2520]

1970. Like it says in the title. And the description.

[@mikestuckinthe70s]

Yeah I see that now I thought at first glance it said 1970’s as in plural .

[@timw.6910]

@@joshuagibson2520 😂😂😂

[@1974rail]

What about guitar amplifier

[@tangoalpha8381]

🏆🏆🏆🇧🇷🇧🇷🇧🇷

[@kehawk2]

Damnit the narrator is uncredited! It sounds a lot like Alex Trebek! Could be just about anyone else who grew up in Ontario, I suppose...

[@clarencegreen3071]

Book: Theory and Servicing of AM, FM, and FM Stereo Receivers. Green and Bourque, Prentice Hall, 1980. My posts keep disappearing. Sorry. This is my fourth try.

[@MoeLarrycurly1]

,👍👍☺️

[@goodun2974]

No way this is from 1970; 1960 maybe. Notable for what it omits, such as CRT'S, TV cameras, magnetrons etc. Doesn't mention beam power tubes (6L6, 6V6, 6bQ5, 6CA7 etc) which were an American invention to get around paying to use/license the Philips patent on pentode tubes. Also weird that it doesn't discuss directly heated filament tubes vs independently heated tubes with separate cathodes; doesn't mention class A vs AB stages; and shows a diagram with tube grids driven from an interstage transformer, a technology rarely used after 1950 or so.

[@JESUSCHRYSLER5512]

replying to @goodun2974: YOU FORGOT THE 6 **B** OWEL **M** OVEMENT **O** OUTPUT TUBE 6 **B M O** TUBE.

[@MichaelSmith-rn1qw]

This video just covered the basics. You gotta go to Uncle Doug or Psionic Audio for in-depth content.😃 (Speaking of Psionic Audio, has anyone heard from Lyle lately @good 'un?) It's not like him to go 2 weeks without posting a video.

[@goodun2974]

@@MichaelSmith-rn1qw , I think Lyle's on vacation in Europe right now. And yes I have been watching both Psionic audio and Uncle Doug for some years now.

[@gordonwelcher9598]

It looks a bit older to me, maybe 1960, 1965.

[@JESUSCHRYSLER5512]

VACUUM TUBES HAVE TINY VACUUM CLEANERS INSIDE THEM, THAT IS WHY THEY ARE CALLED **VACUUM TUBES!!**

[@ClausB252]

You're not far off! They have 'getters' which absorb stray gasses and maintain the vacuum.

[@tomstrum6259]

Was actually 1880 that Edison's research Team of mechanics, engineers & scientists at Menlo Park Laboratory while trying to Perfect the electric Lamp's useful lifetime would 1st discover the added isolated metallic "Plate" wire element 1 way polarity sensitive Polarized "Edison Effect" dc current Flow thru a non-conductive, isolated Vacuum tube atmosphere....This being the 1st unrecognized "Electronic" electron flow thru a vacuum Insulated device was Patented in 1883 & ignored for more immediately Important electric lamp & required supporting electric power Generating plant equipment....Would be 24 yrs Later before John Fleming would Rediscover Edison's tube & rename it the "Fleming valve" while working for the Marconi radio company looking for a better more stable improved Sensitivity radio wave Detector device....There Wasn't any American rf Radio technology around during Edison's vacuum tube current discovery....

[@auyemra1331]

this is basically the same tech we use today, but on a much smaller scale?

[@monicaperez2843]

Vacuum tubes are now mostly replaced by microchips, thousands of which can be on circuit boards.

[@lwilton]

A standard transistor is more or less the equivalent of a vacuum tube triode, but it doesn't use a filament and heat to produce the current flow. The names are different: grid = base, anode = collector, cathode = emitter. But you get the same results for the same actions. There is one technical difference: a vacuum tube is a voltage amplifier, and a transistor is a current amplifier. This means you have to design things a little differently, but not much. A solid state diode and a vacuum tube diode also do the same thing, but the solid state diode is hugely more efficient and capable. It was a rare tube that could carry 1 amp continuous from plate to cathode, but a standard 1N4004 diode about the size of a grain of rice can do that easily.

[@arwah97]

Except my electric guitar amp.. identical tech 😊

[@dziban303]

Canada eh

[@Swervin309]

Cathode, anode, diode, pentode... No mention of commode. 😔

[@malcolmwhite6588]

They were crappy that’s why no mention 😂

[@briankerr4512]

Tubular dude

[@phonotical]

"the triode is amplifying"... Its out of phase!

[@aaax9410]

this is out of control

[@chillydawgg4354]

Tyube

[@videolabguy]

Edison was trying to prevent the build up of soot on the inside of the bulb during the carbon filament phase of his research and development. He did not place "a wire" in the bulb. It was a metal plate with an electrical charge intended to attract the boil off of carbon atoms and keep them from condensing on the relatively cold glass envelope. Edison discovered that current flowed from the filament to the plate in only one direction. He had created the first rectifier vacuum tube and did not understand the significance of his discovery. Realize that Edison was "a DC man" and he despised AC current. (He couldn't do the math! So it must be no good.) That the heated filament emitted a cloud of electrons and that the electrons only flowed in one direction (cathode to anode) is the proper definition of the Edison Effect.

[@michvod]

Why put a watermark and time counter on that thing? It gets quite annoying after a minute... and serves no purpose!

[@PeriscopeFilm]

Here's the issue: Tens of thousands of films similar to this one have been lost forever -- destroyed -- and many others are at risk. Our company preserves these precious bits of history one film at a time. How do we afford to do that? By selling them as stock footage to documentary filmmakers and broadcasters. If we did not have a counter, we could not afford to post films like these online, and no films would be preserved. It's that simple. So we ask you to bear with the watermark and timecodes. In the past we tried many different systems including placing our timer at the bottom corner of our videos. What happened? Unscrupulous KZbin users downloaded our vids, blew them up so the timer was not visible, and re-posted them as their own content! We had to use content control to have the videos removed and shut down these channels. It's hard enough work preserving these films and posting them, without having to spend precious time dealing with policing thievery -- and not what we devoted ourselves to do. Love our channel and want to support what we do? You can help us save and post more orphaned films! Support us on Patreon: www.patreon.com/PeriscopeFilm Even a really tiny contribution can make a difference.

[@bussi7859]

This is 70 years overdue, crappy

[@pairojeans]

Lol as usual American is ignorance of the truth!! Thomas Swan filed his patent for the lightrbulb one year before Edison. Without Newcastle upon Tyne, UK the world would be living in the dark ages!!! Thomas Swan - Lightbulb Charles Parsons - Steam turbine (power generation)

[@shaggydogg630]

Was Lee deForest a genius or did he just get lucky? Anyways he revolutionized electronics.