Vacuum Tubes: Episode 2 - The Triode (Part 1)

In this episode we build upon our new found knowledge of vacuum tube diodes and take a look at one of the most ubiquitous vacuum tube types out there: the triode.
I do recommend checking out the episode on diodes as that background is definitely helpful in wrapping our heads around the triode.
Vacuum Tubes: Episode 1 - The Basics and the Diode
• Vacuum Tubes: Episode ...

[@leosbagoftricks3732]

Great video! Understanding Vacuum tubes really helps with getting the fundamentals of electronics. I was a little confused by the notion that the transistor circuit is "Digital" and the tube "Analog" not really the case, really you are demonstrating the Vbe threshold voltage of the transistor, which a vacuum tube does not have.

[@UsagiElectric]

Thank you! You're absolutely right, and you're actually hitting on the topic of the next video in a sense - trying to get the vacuum tube to cutoff. I think my usage of the terms "analog" and "digital" may not have been the most accurate, but growing up I always heard that tube amplifiers were analog and solid state amplifiers were digital. And this makes a bit of sense as the tube very faithfully recreates the input signal, only larger. Of course, there are many different types of transistors with wildly different properties, so the reality is much more of a grey area than what I've demonstrated here.

[@jassenjj]

@@UsagiElectric Hello! I really enjoy your vacuum tubes series mainly because you make them work with low voltage (I am on the opposite end with my equipment, B+ is usually above 300V :D). So... both the tube and the transistor are analogue and they will always be. Even the transistors in your CPU are analogue. When you put them in circuits that emphasize discrete steady states (most commonly "on" and "off" for "1" and "0"), only then they are "digital". And both tubes and transistors can be "digital" :).

[@UsagiElectric]

@@jassenjj Thank you! You're absolutely right, my oversimplification of transistors here (and a bit of misuse of terminology) created a bit of confusion. Interestingly, getting the tubes to respond in a digital manner (by forcing them into cutoff or saturation) and building digital logic circuits is one of my main goals! Kudos for running such massive voltage, that tends to scare me, haha. Whenever I'm poking around stuff that might have big voltages, I always try to remember the "one hand in the pocket" rule. Fortunately, it seems tubes perform really well at just 24V!

[@zaraak323i]

The "one hand in your pocket" rule is important, but not foolproof. This fool (me) had a cap charged to over 600V discharge through his index finger in three places when trying to replace a melted fuse holder. You can believe that I have a very healthy respect for tube equipment.

[@kasel1979krettnach]

the more I watch it, the more i hope the video can be polished a bit in the future, as the risk of confusing beginners is quite high. although it has some advantages sometimes to not "overthink" and memorise just some behaviours of components. Also the grid is typically controlled with negative voltage, and not positive (thereby drawing current) as in the video.

[@videotaperetro1126]

Hello, well explained and not as hyperkinetic as many youtube videos. Glad to see someone is bothering to explain this technology. But I have to tell you that your idea of ​​tansistors is wrong. A transistor is as analogous as a vacuum tube. But it works with different voltages and impendances. A tansistor as well as a vacium tube can be set to work as a switch. But also both as a very analog amplifier. Otherwise we wouldn't have music amplifiers with transistors today! And this: The first digital computers worked with vacium tubes! And before with relays, now those were the only 'digital' components. You can only close or open them! The fact that something is digital is actually an interpretation of a signal. An agreement, which is a 0 or 1, we agree on and call it digital. So basically there are no 'digital' components. But we construct the circuits in such a way that they work within very strict standards (voltages) and therefore 'switch' at very strict voltages.

[@UsagiElectric]

Thank you so much! It's interesting to go back and watch this video. Even though it was only about 8 months ago that I made it, it feels like a lifetime (my hair is dramatically shorter!). My presentation style is a little laconic and I'm a bit more expressive in my newer videos, but not quite as hyperkinetic as most KZbinrs. I think I'm finally starting to get a little more comfortable in front of the camera! Thank you for the insight into the transistor. That's the only part of this video that I don't like because I got it so wrong, but I'm glad I did. There's a ton of comments on how transistors work properly and I've learned so much since then due to the continued dialogue with the community who watched this video! And you should definitely check out some of my newer videos, building a vacuum tube computer is my current long term project! (Or check out some of my older videos for some relay calculators, the Hexadecimal calculator is pretty similar to an extremely simple computer.)

[@adam207321]

If you were to put a J-Fet instead of a transistor in there you would have a more accurate representation. Since a transistor is a current controlled device. Your 1/16th turn goes like this: you hit the .5V threshold and the base current shoots right up. If you were to current drive the transistor you would have the same effect as voltage driving a tube. Except now the tube would go from 0 to 100 very quickly because the input impedance of a vacuum tube is basically almost infinite for DC ....notice how I said almost

[@UsagiElectric]

Including the transistor is probably the only part of this video that I regret doing. I do think it's an excellent comparison, but I simply don't know enough about transistors and FETs to make that comparison properly. Tubes are just so much easier for me to wrap my head around! Semiconductors always throw me for a loop because they can have such varying properties and reactions. Besides, tubes look way cooler and that's the most important thing!

[@adam207321]

@@UsagiElectric hah they do look a lot cooler I agree on that :D Here is the catch: Tubes and transistors are both analog, just in a different way. In a vacuum tube enviroment when you look at the conductance chart you see a V/I chart. It basically tell you for a given voltage on G1 what current should yo expect on the anode give a voltage on it and you can figure out from that its linearity. In a transistor enviroment you will see a I/I chart..very rarely but lets assume its there. You would see for a given current on the base how much current to expect on the collector. Transistors are much easier to understand when you actually break it down. They are basically current multipliers. Whatever base current get multiplied by the beta of the transistor (gain). A similar thing occurs in vacuum tubes but instead of multiplying grid current (none to speak of) the graph shows a V/I chart. For a given grid voltage how much current is going to be conducted between the plate and cathode. And this number can also HEAVILY vary under different anode voltage conditions especially at low voltages it becomes quite chaotic and difficult to measure. That said if you make the tube circuits into high enough impedance the second tube after that will have no problems reading that voltage on the grid because it does not load it. That grid impedance is upwards in GIGA ohms. You can make a tube computer that has higher impedance circuits than your multimeters input. Ofcourse noise will be a huge problem in such high impedance circuits (Just check out some neumann tube microphone schematics. The U67 had quite the large bias resistor on the grid of the EF86 in there )

[@simonkormendy849]

Bipolar transistors, such as the BC108, and etc are current controlled devices, whereas JFets and Mosfets are voltage controlled devices like vacuum tubes.

[@russoft]

Uhhh, that transistor is used in analog and digital circuits. The difference is that the biasing point is different. Once that's right, much small signals result in much larger output (more gain). At least that's what I'm seeing here.

[@UsagiElectric]

You're absolutely right. I got so much wrong about the transistor in this video and few other commenters have let me know as well, but I'm always happy to see more, great information about how transistors work! Transistors are a bit magic to me though, I'll stick with hot electrons for now, haha.

[@dustinolsen4994]

Just a note indirectly heated cathode tubes were designed to reduce noise so you can use AC on the filament and for isolation of the cathode for "self bias (cathode resistance)"

[@kaypope1581]

I have been searching so much to find a vacuum tube video and finally I am here. Thank you so much for posting the video!

[@UsagiElectric]

Thank you for checking the video out and welcome to the channel! Let us know if you have any questions or something in specific you'd like to see!

[@ivan71538]

There are differences in working conditions between a BJT and a triode, so the comparison is not fair to the transistor. The transistor only works linear in a certain bais, so you shouldn't make a digital switch circuit by BJT then tells everyone transistor is "digital" or non-linear. (I know you didn't use the word "linear", I assume the word "analog" is the same meaning) (Needless to say, linearity can not be defined by the lightness of a LED as well, ) And the definition of "better sound" is not to recover the sound signal, people like tube amplifiers because they generate sound with a special taste of flavor. Which has the opposite meaning of what you said, a good signal recovery ability. I've seen that you said when you were learning these things you kept hearing people said triode is analog and the transistor is digital. These comments may come from someone that likes tube audio amplifier rather than transistor amplifier. Which is not accurate in electronics engineering. I know this explanation is easy to understand. But I think it is better to use accurate and correct terms and viewpoints when making a video to teach someone new to this area. So that people would not misunderstand. Despite that, I think your video is great on teaching tube applications. This is why I write these words and hope more people knowing the beauty of electronics engineering through videos like yours.

[@UsagiElectric]

Thank you so much and thank you for checking out the video! I got a hilarious amount wrong about Transistors in this video (which is why I haven't really done anything with them in videos since, haha). But you're absolutely right and this is definitely excellent for anyone looking for a more accurate understanding of what's going on with the silicon in this circuit!

[@ivan71538]

@@UsagiElectric Thank you for your kind reply. I was a student in electronic engineer. I am interested in tube circuits and decide to make a tube amplifier recently. But recent textbooks have removed content related to vacuum tubes. And I didn't have any experience in tube circuits (except for a nixie tube. Of course it is much easier to use compare to triodes). Then I found your video that makes a tube circuit so vivid that I can imagine how to build a circuit in tubes only by watching your videos (Formulas are so boring that they only stay on the paper, I need images in my head to design a circuit). While finding some mistakes in the video. I thought if there were people that have no experience would misunderstand something. So left a message for you. At the same time, I apologize if there is any improper vocabulary in my words. I am not good at English. Anyway, your video does make a difference. Thank you for making these videos.

[@waltwimer2551]

I came here to mention this same issue, so I'm glad you guys covered/corrected it. Vacuum tubes, BJTs, JFETs, and MOSFETs all have similarities and important differences. They can all perform analog or digital functions. I'm a EE. In my junior level digital integrated circuits course, my professor pointed out on the first day of class that all "digital circuits" are actually *analog* circuits that we ask to perform digital functions. This is very important to keep in mind as clock speeds increase, capacitive loading increases, etc. :-) Otherwise, great videos! Keep up the great work!

[@stamasd8500]

Also, BJTs are controlled by a current (base current) whereas vacuum tubes are controlled by a voltage (grid voltage). In that sense, vacuum tubes are more akin to FETs than to BJTs. JFETs and MOSFETs are also controlled primarily by a voltage, not a current.

[@patrickcraenen5163]

Nice video but the transistor circuit is just as analog as the vacuum tube circuits on your breadboard.

[@UsagiElectric]

You're absolutely right! I way, way oversimplified here, to the point of actually being incorrect, haha. This is quite an old video, and I've learned a lot more about both tubes and transistors since this video, so hopefully my more current videos don't suffer from quite as many inaccuracies.

[@grokwhy]

Solid-state would be a better choice of words

[@saturn5tony]

Well done, this was very very cool, thanks for sharing 😊

[@gooball2005]

you said that the transistor doesn't want to be in the in-between state. don't you mean that it just has a higher gain? why not just add an emitter/source resistor?

[@UsagiElectric]

Thanks for the comment! My wording is probably not the best, but if you look at this 2N2222 datasheet (www.onsemi.com/pub/Collateral/P2N2222A-D.PDF) and check out the "Collector Saturation Region" chart, it shows a great graph mapping the base current against the collector-emitter voltage. My semiconductor game isn't as strong as it should be, but if I'm reading the chart right, the collector emitter voltage changes rapidly with a very small change in base current. For example, if the collector current is 10mA, the collector-emitter voltage changes from 1.0V+ to less than 0.1V with just 0.05mA change in the base current. This is what I'm referring to when I state the transistor doesn't want to be in the in-between state. It takes very little current to change from an very high collector-emitter voltage to a extremely low collector-emitter voltage. If you compare the 2N2222 "Collector Saturation Region" chart with the 6DJ8/ECC8 vacuum tube "Plate Characteristics" chart (frank.pocnet.net/sheets/030/e/ECC88.pdf), the lines look wildly different, with the tube exhibiting a much more linear change.

[@tossedsaladandscrambledegg8576]

Oh man! I am having flashbacks to my Naval Electronics courses at NAS Memphis in '84.

[@skyfreak73]

This whole series is fantastic, but this episode made me appreicate the smooth curve of a vacuum tube vs the hard cutoff of a solid state transistor.

[@easton79]

Really great video. Best explenation of vacuum tubes I have seen. In all their simplicity vacuum tuubes are a really facinating piece of engineering.

[@UsagiElectric]

Thank you so much! I think they're absolutely fantastic pieces of technology and they require a bit of lateral thinking, especially when using them in digital computation circuits, which we'll get into in a bit more detail in a few episodes!

[@jensschroder8214]

What is the difference between a vacuum fluorescent display (VFD) and a vacuum Triode? - A VFD has a heater that is also a cathode. directly heated cathode. - It has a control grid that is switched to positive volts. Some have multiple grids to switch groups. - And it has an anode, but with a luminescent layer. For example, a 7-segment display. Except for the luminescent layer and the mechanical structure, a VFD is a Triode. Heating voltage 1 - 3 volts. Anode and Grid voltage 10 to 30 volts.

[@adailyllama4786]

I have been looking for an instruction on how to wire and use vacuum tubes. Finally a very simple and straight forward example of a triode. Thank You!

[@UsagiElectric]

Awesome, I'm glad my video could help!

[@sivoltage]

Thank you, concise and easy to understand. Really great example of what's actually going on in those mysterious glass lanterns!

[@UsagiElectric]

Thank you! I'm glad you enjoyed the video!

[@shortridgegregory]

This is an excellent explanation of the Triode. Thanks!

[@possible-realities]

5:00 When the grid voltage becoms positive with respect to the cathode, I believe that you start to get grid conduction - you get a forward biased diode between the grid and the cathode. Afaik, most vacuum tube circuits try to stay away from this region, but I know there are uses for it as well. At least you want to make sure to limit the grid current because it's probably not built to handle as much current as the plate and cathode.

[@yvesbouchard5197]

Well done! Excellent straight-to-the-point presentation of tube analog signals. It's amazing how getting to understand thermionic emission helps in understanding PN junction. Many thanks!

[@UsagiElectric]

Thank you so much! I've learned so much about the fundamentals of electronics and things I never would have learned otherwise by playing around with tubes. Just thinking in how electrons flow makes a massive difference!

[@edb1149]

Thank you for the time and effort you spent to produce this quality and informative video. Well done!

[@simonkormendy849]

Since the 6DJ8 vacuum tube has two triodes in it, you should be able to build a simple flip-flop circuit with just a single 6DJ8 and all the necessary resistors, caps and etc.

[@simonkormendy849]

Bipolar transistors, such as the BC108, and etc are current controlled devices, whereas JFets and Mosfets are voltage controlled devices like vacuum tubes.

[@stamasd8500]

Triodes are essentially transconductance amplifiers: a small voltage in the grid circuit controls the current in the much higher voltage plate circuit. Sure, you can convert that current to a voltage using e.g. resistors and such, but they are primarily voltage-controlled current sources. Modern transconductance opamps like the 14700 do the same, and like them they are used in high-end audio equipment.

[@Otakutaru]

I must say... you're not doing the transistor justice by wiring it like that. To take advantage of its active mode just put some resistor between collector and base. Doing just that and tweaking some resistor values will make it much more linear BJTs are current based, tubes are more voltaje (signal) focused AND COOLER, that's the upside EDIT: Just realized the barrage of elec-heads bashing on the exact same thing I just said, sorry~

[@MostlyPennyCat]

So. When the grid is pulled to -10V, it's the same as disconnecting the center tap and all the current flows through the LED at 24V. Current address the LED will be: I = V / r¹ + r² If you pull the grid to 0V and let's say that's max open, you have zero resistance to ground so all the current will flow through the valve, with the current: I = V / r¹ What happens with the grid set to 50%? What electrical property of the valve changes? Is it resistance? What is the voltage at the anode/r¹/r² junction? How do you calculate it? What's its resistance?

[@RonRohde]

Hey there great job putting this together!

[@UsagiElectric]

Thanks a lot man!

[@ianhokai6316]

Thank you. Just discovered your channel. Great content.

[@UsagiElectric]

Thank you!

[@ChrisPinCornwall]

This series is SO interesting. Thank you very much.

[@markpoling7917]

Thanks for assembling these videos on tubes. I am just getting started on your series. I have however watched other videos, some are really good as well, but I still cannot find an answer to a couple of things. If I may ask a couple of questions that would be great: 1). If and when you apply a full or close to full voltage on the grid, why don't the electrons just collect on the grid? Unless the plate voltage is just so high the electrons just don't have time to collect on the grid? 2). We talk about amplification, so I believe I understand, but not 100%. The amplification is a function of the B+(plate voltage), so with a fixed plate voltage the amplification is fixed as well - cannot be anymore unless we increase the plate voltage? So, in order to change the amplification we need to change the plate voltage accordingly + correct? Your response is appreciated!!

[@armitage64]

Great video, very concise and informative. I wish they had covered some of this stuff back when I was in school but it was considered obsolete even back then I guess.

[@UsagiElectric]

Thank you! To be fair, the first vacuum tube, the "Audion tube" was built in 1907, so this technology is well over 100 years old now! The 6DJ8 tubes I'm using have build dates around the late 50's and early 60's, so even those are still 60 years old now.

[@nickxia3209]

nice video, thank you very much, but cannot find part 2.

[@harmonicseries6582]

transistor is analogue as well, I think what you mean is solid state rather than digital

[@pawan19]

Thanks sir

[@UsagiElectric]

Thank you!

[@rsauve123]

But what about the poor old npn transistor? It was operating as a switch, not biased for amplification. Its either in saturation or its off. However, tubes are fascinating, thank you for the most excellent videos. BTW, those electrons actually travel quite slow, about waking pace (3 ~ 4 km/h)... Sorry, forget that. I am not thinking vacuum tubes here but copper conductors.

[@Apurbo_D1]

In the amplifier, will the phase between an amplitude be same on wave (1) and wave (2) or will the frequency in wave (2) increase comparatively to wave (1)?

[@crissd8283]

A transistor itself is certainly not digital. It is fully analog. It may have higher gains/beta. A BJT is a current analog device not a voltage device.

[@antoinestevan5310]

Very interesting and clear ! However, I was sad at the end when the video was over... Where do you actually get your parts ? It seems pretty hard to find vacuum tubes (or relays in an other style of electronics) and even transistors :-/ Looking forward to your next videos !!

[@UsagiElectric]

Thank you so much! I try to keep the videos under about 20 minutes, otherwise I tend to get a little long-winded, haha. Vacuum tubes are surprisingly common, you just gotta look in the right place. If you're looking to salvage, keep an eye out for oscilloscopes from the 50's and 60's, they often had anywhere between 10 and 100 tubes inside depending on the model. Although, you can also find tube lots on eBay for decently cheap. The audiophiles definitely hunt down some of the more desirable tubes, like the 12AX7 and 6922, and they can get quite expensive. But, if you're like me and are looking for some tubes to just play around with, you can often find the old TV and Radio tubes for really cheap. They won't be the best in amplifiers, but they work great for making random circuits with. For example, I picked up a lot of 600 tubes on eBay for $75 shipped. That comes out to just 12 cents per tube, which is super cheap. About 200 of the tubes were either 6CB6s or 6AU6s, which are 7-pin pentodes, but even those can be used for interesting inverters and what not. I'm planning to go in depth on Tetrodes and Pentodes after I wrap up the next Triode episode!

[@cgeorge6786]

You can really learn a lot by bread boarding. Why is it called a bread board? Never thought of that before. Can't a transistor do analog just as well as a tube if set up to do so?

[@chalycanmonroe]

It's the Gold the stuff of STARS is what makes all that amplication possible

[@JurassicJenkins]

Love the explanation. But I’m quite sure all electrons are the same size 🤔 🤣🤣🤣 - Also I absolutely love your breadboard vacuum tube setup. I’m going to set one up 💯

[@MechanicForGMCCars]

I wish that you wuld experiment on ignition systems honestly. I have years problem to build variabel voltage regulator solid state for alternator or controling precisely ignition module pulse duration aperantly such devices do not exist . So I have hard time controling alternator and ignition coil . Some peopel mentioned wacum tube baterry chargers please rewive those so I can understand how they work. Your videos are great and in detail realy great chanel . I also wish you wuld revive those old amplidyne generators ,M-G Sets ,Metadyne and other interesting things used in the past. I have so much unusual effects on me engine that I need badly help .

[@MrTylerStricker]

Welcome to the grid!

[@itzanitzit]

What is the make/model of the vacuum tube twin triode?

[@SergioVelasquez-cs4ei]

Hola, buenas tardes. Es agradable saber todo lo que Ud sabe sobre tubos de vacío y las aplicaciones de los mismos. Entiendo lo que dice pero me es un poco difícil decírselo en su idioma. Tal vez tenga respuesta, tal vez no. Mi pregunta es : ¿Porque la cantidad de válvulas del mismo tipo diodos, triados, tetrodos, pentodos etc,? Entiendo que tienen diferentes voltajes tanto para los filamentos como para el resto de los componentes Porque los diseñadores de radios e instrumentos electrónicos usan tanta variedad de un mismo tipo de bulbo. ¿Porque nos encanta complicarnos la vida? Cada maca de bulbos tiene todo un catalogo de cada uno de los tipos de bulbos que fabrican pero en muchas ocaciones no son intercambiables. ¿No existen estandarizaciones Normas para la fabricación de los mismos.

[@slivkask8329]

Thank you for the nice and interesting video! 👍 I want to point out the mistake you have made in the naming. Transistor and semiconductor electronics in general are not digital at all, they are still analog, and the behavior you observed on the LED connected to the transistor is due to the physics and behavior of the P-N junction. If you connect a voltmeter to the output, you will see that the voltage changes on the LED are still linear (analog) and not discrete (digital). Another point I want to make is that explaining the behavior using inverted logic is confusing. It would be better to use the non-inverted output.

[@rudiardialvarenga3018]

Nice video

[@UsagiElectric]

Thank you!

[@russtuff]

My mind is blown

[@larryshaver3568]

is a 6DJ8 similar to a 6EU7?

[@UsagiElectric]

The 6EU7 has a very interesting pinout, despite being a 9-pin tube. So, it's unfortunately, not interchangeable with any of the standard 9-pin tubes without an adapter. The 6EU7 is also very different from the 6DJ8 in terms of electrical characteristics. For example, the 6DJ8 at 100V with 0V on the grid is moving around 40mA through the plate. The 6EU7 at 100V with 0V on the grid is moving just 2.5mA. But the 6EU7 is very linear, so it could work pretty well as an audio pre-amplifier tube or something like that.

[@larryshaver3568]

can you do a video discussing how red-plating gets started?

[@UsagiElectric]

You know, that's something that I've always been curious about! That would definitely be a fun video to make! Hmm, I have a few ideas of how I could tackle demonstrating it really well, and I have enough spare tubes that we could sacrifice a few in the name of science. I'll definitely give that a go for a future video!

[@juniorkong9587]

Thanks boss I really like your show.

[@UsagiElectric]

Thank you! And thanks for checking the videos out!

[@juniorkong9587]

@@UsagiElectric You are welcome, I subscribed in the first minute..that says something. I will watch the rest of your stuff too. 12ax7/ecc83 and 5881 fan here for life. 6L6 too.

[@UsagiElectric]

@@juniorkong9587 That's awesome to hear, thank you! The 12AX7 and 6L6 are excellent audio tubes indeed! I unfortunately don't have any floating around, but I do have a pair of 6080 (6AS7 equivalent) power tubes I'd love to build something with someday. But, I think the ultimate goal is to get my hands on a GU-81 and build the physically largest mono amplifier ever, haha.

[@juniorkong9587]

@@UsagiElectric You'd naturally make a great science teacher. Maybe it is your occupation now. The best teachers are the ones excited about the subject.

[@UsagiElectric]

@@juniorkong9587 Thank you so much! My day job, up until 2020 at least, was as a translator and technical trainer, so I wasn't unfamiliar with speaking in front of people, but speaking to a camera alone in a room is a whole different level of skill set! It's been a lot of fun though!

[@ronliebermann]

I really like these videos, but remember that most people aren’t familiar with using power to control a dimmer switch. After all, that’s a triode. You’d be better off showing a mechanical slider, then a power-operated slider, then a transistor with variable voltage input, then a vacuum tube. People need to see the progression of ideas.

[@isbestlizard]

You're being very loose with words.. the grid has a 'charge' which seems linked to its potential but how does that work, if all potentials are measured with a difference to on another. Is there an ABSOLUTE potential of 0, above which electrons are attracted and below which electrons are repelled? I seem to have mental conflict resolving the idea of absolute electrical charge with electric field potentials :/

[@oskimac]

The grid job is being the digital frontier...

[@larryshaver3568]

i had a Magnavox like the one the was just shown at 7:27

[@UsagiElectric]

I think perhaps this comment was intended for a different video, but our Magnavox Concert Grand console stereo makes one of the absolute best sounds I've ever heard, I absolutely adore it!

[@larryshaver3568]

@@UsagiElectric it probably was but wish i could find another{Imperial] in like new condition

[@larryshaver3568]

it was actually at 6:43

[@georgytelelyuhin3175]

Hey, I really like your videos and it's a shame you don't have more viewers. I would sudgest you try making you videos a bit shorter and a bit faster (not talking about this video but just in general) This explanation is actually great I wish they explained it that way in my engeneering school.

[@UsagiElectric]

Thank you so much! I do try to keep my videos as short as I can, I aim for between 10 and 20 minutes, but the Diode video got a little out of control, haha. That was actually the primary driving force behind breaking the Triode into two separate videos.

[@comment8767]

Transistors are just a fad that is going to fade away.

[@UsagiElectric]

I'm just out here living my best tube life!

[@TheFaquarel]

Hey i realy like your videos but the explanation why the transistor behaves differently from the tube is not correkt. It is not about "digital" or "analogue" the transistor is also a "analogue" device. It is all about the characteristics in the datasheet. For example, the transistor (a bjt in that case) is a current controlled device. A current flow in the base controls the path between the collector and emitter. When you let a lot of current flow into the base the transistor satturates and it turns on the collector emmiter path completely and when you let no current flow into the base than there is no collector-emmitter path. You have a linear region in between where the path is kind of a adjustable resistor and that is the region you use when you "amplify" a signal so you basically modulate the voltage between the collector and emmitter with the current that flows into the base. The Tube behaves like a mosfet because it is voltage controlled. It is all about the info in the Datasheet. (sorry for the bad grammar and orthography, i am not a native english speaker )

[@UsagiElectric]

Thank you! First of all, your English is amazing for a non-Native speaker! Like better than most native speakers I know, haha. Also, you're absolutely right. I got so much wrong about the transistor in this video and few other commenters have let me know as well, but I'm always happy to see more, great information about how transistors work! Transistors are a bit magic to me though, I'll stick with hot electrons for now, haha.

[@tobias8488]

18:39 ich kapiers es nicht wieso fällt an Ra die Pannung ab die Zeichnung zeigt dich dass der spannungs Abfall über der röhre ist

[@AureliusR]

Awesome video, right up until the point you called the transistor "digital" and the tube "analog". Both are analog parts, and what you were demonstrating was not what you thought you were demonstrating... :(

[@frankowalker4662]

I repaired valve equipment for many years, I never thought to run them under 200V. LOL.

[@UsagiElectric]

Really, I'm so accident prone (I've cut myself with a butter knife before), I knew that with hundreds of volts on tap, it'd only be a matter of time before I hurt myself, haha. So, I figured I'd give tubes a shot at low voltages. And, for computing applications, it turns out they tend to work really well!

[@frankowalker4662]

@@UsagiElectric Yeah, they're working realy well. Back in the 80's, I was building a totaly valve 40watt per-chanel quadrophonic entertainment system. I was doing final checks on the output stages when I got a 1200vdc shock that threw me across my bedroom. I did'nt stop shaking for hours. LOL. After a few days I finished the system and it sounded brilliant. We had it in the lounge for about 5 years till we moved to a smaller place with nowhere to put it.

[@antoniograncino3506]

Vacuum tubes are to diode for !

[@UsagiElectric]

I'll triode to come up with a solid pun to reply with!

[@nepaliangusyoung]

Logic gate Transmitter receiver

[@jannepeltonen2036]

Running vacuum tubes at low voltages was really interesting, so I did some digging around, and found this paper www.valvewizard.co.uk/Triodes_at_low_voltages_Blencowe.pdf which also confirmed that you can set them up as linear amplifiers at low voltages (in that paper, less than 12 V) but you do have to throw some conventional wisdom out the window. Really interesting!

[@UsagiElectric]

I haven't actually done much experimenting with tubes at low voltages for audio applications, but that's an excellent paper! I've got it bookmarked and will sit down and give it a proper read. There's a lot of really interesting tricks they're doing to get the tubes working well at just 12V, but it's super impressive. I may have to build something based on that paper one of these days! Thank you for the link, that'll be a fun read indeed!

[@DonnyHooterHoot]

1T4

[@ryanbeard1119]

Probably the easiest way of , teslaING

[@Ammi6543]

While I enjoy your teaching of how vaccum tubes work, I think your understanding of BJTs (and possibly transistors more widely) flawed. A BJT is an analogue device, not digital. What you observed was the higher gain of the BJT compared to the triode along with the higher efficiency resulting in a digital-like behaviour. It is intact these very properties that make a BJT good for certain analogue applications (compared to a triode). A BJT can act similar to a triode within its linear ranger, however is a current controlled device as opposed to voltage controlled, so won't behave the same.

[@nepaliangusyoung]

IC Bip digons card

[@bussi7859]

Crap

[@simonkormendy849]

Since the 6DJ8 vacuum tube has two triodes in it, you should be able to build a simple flip-flop circuit with just a single 6DJ8 and all the necessary resistors, caps and etc.