Thank you so much for this. I just inherited my grandfathers Eico 666 and 667. He was a TV/Radio repairman in the 50's-70's. When I was very young I would sit next to him and watch him work. I now have gotten into electronics repair as a hobby and have so many questions for him. Unfortunately he passed a number of years ago. Watching this I imagined I was sitting next to him again, and your description of tube electron flow is exactly how he would have described it to me :)
You really know how to transfer knowledge. This video is for me the best video explaining tubes (being born in 71). Thanks very much for making this video!
This will be one of the best teachings on the operation of tubes.I am 67 yrs old and no one has explained it so you can understand it as well as you.This will be on youtube through history, you have made your mark in history. This will be here long after you're gone. Great job!
If the average college class has 100 students in it. And the average professor teaches 4 class a year. A college professor will teach 400 students per semester for 800 students for a year. If we use those numbers. It would take approximately 20 years for a college professor to teach the amount of people of this man is reached. And this guy did it for free. TH-cam needs to be more like this
Four years after you put this out, I caught it on TH-cam. As others have mentioned, I had VT Theory in the 1950's in high school. with Covid-19 keeping us home, I decided to get a refresher. I have to say that your teaching method is far superior to anything I had back in the day. Thank you Tom.
I'm 22 in my high-schools electronics course. we learned what a capacitor was... however, TO DANGEROUS TO TOUCH! My generation is mentally handicapped...
I’m 33 years old. I’m just a hobbyist who likes tinkering. I’ve recently become obsessed with vacuum tube circuit designs and theory. I would give damn near anything to go back in time and take a course on tubes in their heyday, and this video series you have done is the closest to that I think I’ll find. I can not thank you enough for taking the time to dust off your teaching cap and share your priceless knowledge with us in a form that will be available for a long time to come.
Hi, Tom? You got my tube mentor today afternoon. Very well done, thank you for sharing and explaining this stuff. Interpretation of datasheet parameters for tube selection or operation point considerations would be a clear reason to watch further. Also, I have not seen anyone touching power dissipation of tubes (so far I have only seen this video of you) C.u.
I'm an audio repair tech, old enough to have learned about and worked with tubes before I even reached adulthood. This is an excellent tutorial for newbies. A couple of related tidbits that they may find helpfull: early *direct-heated* tubes, where the filament IS the cathode, typically had to be heated by DC because an AC heater voltage would inject a lot of hum into the signal, which is why the earliest radios were invariably battery powered. An independently-heated cathode, with the filament inside an insulated cathode sleeve, could be heated from AC voltage without injecting massive amounts of hum into the signal, so that radios could be powered from ordinary house current with a simple transformer- fed power supply; and only the tube plates required DC from a rectifier circuit.. This negated the need for frequent replacement or recharging of batteries just to run a radio. Also, the independent cathode allowed other hum reduction techniques (briefly alluded to in the video) such as lifting the cathode above ground, and/or "biasing up" the AC heater supply with a small DC voltage. This also provided more circuit design options for injecting feedback or improving circuit linearity, especially for drivers and phase splitters. Factor in the addition of screen grids that allowed for lower internal capacitance and more stable operation, and the design options increased by leaps and bounds. Tubes with independently heated cathodes also warm up more slowly than the filaments of indirectly- heated tubes, and are better insulated against arcing; this is why a 5AR4 (GZ34) is a more desirable rectifier tube for power supplies because it doesn't shock the filter caps and the other tubes with nearly immediate high voltage like a 5Y3 or 5U4 filament-type rectifier does; the 5AR4 also has less internal voltage drop under load due to the close spacing of the cathode and plate, providing improved efficiency (a filament rectifier requires greater spacing between elements to prevent arcing). By the way, some of the very earliest tube types did not have "coated" filaments for providing emission, Tungsten filaments impregnated with Thorium were used in a few consumer-level "recieving" tubes (such as the WD11, IIRC, or was it the 199?), and Thorium-impregnated filaments were (are still?) often used in commercial transmitting tubes. Hot flash: when such tubes become weak, a brief period of running the filament at double or triple the normal voltage will bring fresh Thorium to the surface of the filament and restore operation. Unfortunately this doesn't apply to most "modern" tubes found in radios, hifi and guitar amps....
Those old school varicaps are works of art! That's actually what first got me into electronics, fiddling with the tuning on an old broken radio whilst peeping through the vents in the back and watching the varicaps move... I was pre-school and had no idea what I was looking at... but I really really wanted to find out.
I know it is an old TH-cam video but i was actually taught this in the Army in 1991. I was in an Air defense unit that still had 1 radar built in 1938 and it was a blast to work on. We used a slightly different book but do remember the same diagrams and taught the exact same way. I remember as a young kid in the late 60s and early 70s you could still get the Popular Mechanics magazine that would give simple circuits to build and experiment with. Good job Tom with the video brought back a lot of memories and the fun i had doing this. Makes me want to get back in it again on old radios again.
This sir is the best VT video i have seen since i started researching about the subject about a year ago, when i decided i would start restoring old am radios as a new retirement hobby. Your knowledge is just as impressive as your teaching and communication skills and i thank you for sharing all of this with us. Will start watching part 2 ASAP. Also dowloaded the manual which i can't wait to devour. Be well, Go bless
Over the last few years, my interest in vacuum tube has increased, and it's videos like this that really help solidify my understanding of the basic of these fascinating devices. Thank you so much for such a clear explanation.
Ive only just discovered your channel, what a fantastic well explained tutorial you have made here, thank you this was just what i needed, i am about to embark on a journey into power transmission tubes for Tesla coil use & if ime honest my experience with small radio amplifier valves is utterly insufficient for what i am about to attempt. I really needed to understand the principles better & look at how i should be utilising the connections, i have a whopping great GU39-B & i am worried that i might ruin it by making errors, there are more connections than i was expecting on it which has thrown me a little. I have many years experience with solid state coils & sparc gap coils, but i have never attempted a tube coil or a coil capable of such scary power levels. Dont worry ime also a radio fan & i am working in a fully caged environment with a protected off grid supply so i dont upset every radio operator with in 100 miles of me. Ime based in the UK
Tom, You made me feel like I was in college of the 40s and 50s, for the Radio Serviceman, and I was born in ’62. I have been doing vintage radio customer repairs as an electrician with 99% success rate over the past 6 years and always wished to have, far more understanding on more of the technical side and learn from the knowledge from someone like you. I have a 1930 full college text book and 5 volumes from 1950. The way you presented this tutorial was just amazing and appreciate the time and effort you spent doing this video. I think I have learned more in this video than I have in the text book. My hat off to you Sir 👍👍👍
Im 65.. fascinated by this stuff just delving into the nuts and bolts.. a guitar player interested in bulding amps .. and thank you so much for this info 👍👌🙏
I'm old enough to have been taught vacuum tube theory in school, and even having used them in projects around the same time (although the transistor was well established and getting cheaper by the day), and yet find that this lecture is one of the best I have watched on the subject. Good work! It may have been interesting to mention why the beam tetrode even existed, since the regular tetrode problem had been solved so well by the pentode. The answer is, due to commercial interests. The pentode was patented, and as far as I understand it the patent license fees were fairly significant - so other manufacturers tried to get around having to pay the patent fees by building something that reasonably did the same thing as a pentode, without mechanically being a pentode (i.e. not having a suppressor grid). It worked reasonably well, but only at high power - you mentioned that it needs a lot of current to create the space charge that makes the virtual electrode/electron cloud that acts like the 3rd grid. At low powers, the pentode is still the king. Also the tetrode with its kinked transfer characteristic has some applications in its own right; the more pronounced the negative resistance interval is, the better it functions as an oscillator.
One of the best videos on TH-cam, I grew up and got my electronics degree in the transistor age (just) and really appreciate the clear yet detailed explanation, it’s fascinating to learn how this stuff worked, I had no clue the difference between triode, tetrode and pentode and I always wondered why pentode when we get by just fine with 3 terminal semiconductor transistors even now,,well now I know the answer, thank you!
I have thoroughly enjoyed watch and learning from your video. I am trying to learn as much as I can about old vacuum valve radios. I have very limited electrical knowledge and appreciate the time and effort you have put into this tutorial
My dad tried to teach me about vacuum tubes, apparently he repaired t.v sets and radios when he was young, but I was in the cusp of dip integrated circuits. Basically my dad taught me that a vacuum tube is a " valve" . It just controls electrons from one point to another. Similar to a transistor. When he said transistor, I was in some understanding of how a tube works. This is very interesting. So, years later I'm experimenting with a device that I bought off an estate sale. This device uses two OD3a. tubes. I think it's a power supply, just not sure. Good video. Thank you.
Very Generous of you to share your knowledge with us. My interest is mainly in Tube type Guitar Amplification - but your tutorial has helped me envision much better the elements, construction and operation of these fascinating devices. Very much appreciated. Thank you very much. I will watch more of your videos and tutorials. ~ Murph_
OMG, you are an absolute treasure! As I hear more and more about the technical & basic engineering ideas that were taught in years past full confirms my hunch about the utter inadequacy of my 1980's & 90's education at the time I was getting it. I could do calculus all day long but it was meaningless & trapped in a void because apparently it was felt to be too dangerous (or too expensive?) to teach real world applications or the economy of the time assumed that I either needed to program computers or work in a bank. Thank you so very much for sharing this with us.
Bless you for this, without people like you, this part of the electronics world would surely die. i have enjoyed both videos on this. please continue, and you have a great teaching style.
Tom thanks for this amazing and inspiring lecture. You have the art of clear an calmly explain tubes theory. Thanks also for the pdf reference. Maestro! 👌🏾👌🏾👌🏾👌🏾
Funny, I have a similar story. My father, who was in the window business, told me to drop by his friend Emil's house to help me with a kit that was having trouble with. Emil worked for RCA Harrison vacuum tube division in NJ and it was he who taught me how a vacuum tube worked when I was only 15.
Note that the photos of Williamson amps at the end of the video, from Stancor transformer catalogs and so on, appear to be utilizing 807 tubes, a high-voltage variant of the 6L6 designed for ham radio transmitters, with an old-style 5 pin base and the plate connection on top of the tube (to deter arc-over, which might otherwise occur if the high-voltage was applied thru the base, near the other pins). Also interesting to look at the pronounced nonlinearity in the transfer curve of the 6J7, since that tube was often used for microphone preamps in the broadcast and recording industry!
Thank you for taking the time share some old school wisdom, I really appreciate it. I only use tubes for my guitar amps but it is nice to know a bit more about how they work in detail.
I believe these are referred to as thermionic devices. In addition to thermionic emission, most ( not the dc voltage regulator) of the various applications involve the application of time varying voltage as part of some continuity scheme to complete the circuit via the thermionic element. The solid state device version (p-n junction) is basically a drop-in replacement to the thermionic emission device and so eliminating the need for a heater from which the electron mobility is derived. These continuity schemes carry over to circuits having solid state non-thermionic versions of the devices from which electron mobility is derived. But in the solid state world both holes and electrons are referred to a charge carriers. This is a great video that shows the application of vacuum tube technology in example circuits to achieve practical uses of vacuum tubes.
Thanks for your knowledge, very interesting. Tubes something new for me because I work in the RF heat sealing industry where the machines date back to 1960. The technology is older than me but the machines may only have a few years on me.
My Radiola60 has centertapped resistors across the heater leads, the centertap goes to a voltage divider and through the secondary coil and to a grid in the 71A amp tube. I am told I could have too much bias as the set oscilates a lot. If I am correct, taking part of the output to a tickler coil I'd have an oscillator of the Hartley type being inductively coupled or if using a cap, a colpitts oscillator. I had to know all this to get a ham radio ticket and learn morse code too. It was all good, electronic physics.
Great video. I'm trying to get my jukebox amplifier going (it's 40 years older than me!) and the outlined information here is a treasure trove of information. I'll definitely be watching your other video tomorrow and downloading that technical manual. Thanks for putting this online!
If you cant get your Jukebox going without videos like this , you probably shouldn't do it , since Tube Amps are simplest form of Circuit , on a level of a Heater with some controls , you probably shouldn't do it , there are high voltages present , that can be more then nasty . . Non the less im interested , did you get it going or what , somehow i doubt it :)
always wait for the vacuum tube to cool down before pulling it out of the component, those puppies can get really hot. when you see lightening in a vacuum tube when you turn on the component, most likely the vacuum tube is not working right and is going into failure mode.
Thank you so much for this. I just inherited my grandfathers Eico 666 and 667. He was a TV/Radio repairman in the 50's-70's. When I was very young I would sit next to him and watch him work. I now have gotten into electronics repair as a hobby and have so many questions for him. Unfortunately he passed a number of years ago. Watching this I imagined I was sitting next to him again, and your description of tube electron flow is exactly how he would have described it to me :)
You really know how to transfer knowledge. This video is for me the best video explaining tubes (being born in 71). Thanks very much for making this video!
This will be one of the best teachings on the operation of tubes.I am 67 yrs old and no one has explained it so you can understand it as well as you.This will be on youtube through history, you have made your mark in history. This will be here long after you're gone. Great job!
If the average college class has 100 students in it. And the average professor teaches 4 class a year. A college professor will teach 400 students per semester for 800 students for a year. If we use those numbers. It would take approximately 20 years for a college professor to teach the amount of people of this man is reached. And this guy did it for free. TH-cam needs to be more like this
No. College needs to be more like this channel.
Four years after you put this out, I caught it on TH-cam. As others have mentioned, I had VT Theory in the 1950's in high school. with Covid-19 keeping us home, I decided to get a refresher. I have to say that your teaching method is far superior to anything I had back in the day. Thank you Tom.
9
Covid-19 did not keep us home; government response to “Covid-19” kept us home, destroying many businesses.
agreed! He stays on topic! What a wonderful instructor!
I'm 22 in my high-schools electronics course. we learned what a capacitor was... however, TO DANGEROUS TO TOUCH! My generation is mentally handicapped...
I’m 33 years old. I’m just a hobbyist who likes tinkering. I’ve recently become obsessed with vacuum tube circuit designs and theory. I would give damn near anything to go back in time and take a course on tubes in their heyday, and this video series you have done is the closest to that I think I’ll find. I can not thank you enough for taking the time to dust off your teaching cap and share your priceless knowledge with us in a form that will be available for a long time to come.
Hi, Tom? You got my tube mentor today afternoon. Very well done, thank you for sharing and explaining this stuff. Interpretation of datasheet parameters for tube selection or operation point considerations would be a clear reason to watch further. Also, I have not seen anyone touching power dissipation of tubes (so far I have only seen this video of you) C.u.
Totally simple and immediate explanations without fancy intros and "talking heads"... Just perfect. You, sir, should have more followers!
I'm an audio repair tech, old enough to have learned about and worked with tubes before I even reached adulthood. This is an excellent tutorial for newbies. A couple of related tidbits that they may find helpfull: early *direct-heated* tubes, where the filament IS the cathode, typically had to be heated by DC because an AC heater voltage would inject a lot of hum into the signal, which is why the earliest radios were invariably battery powered. An independently-heated cathode, with the filament inside an insulated cathode sleeve, could be heated from AC voltage without injecting massive amounts of hum into the signal, so that radios could be powered from ordinary house current with a simple transformer- fed power supply; and only the tube plates required DC from a rectifier circuit.. This negated the need for frequent replacement or recharging of batteries just to run a radio. Also, the independent cathode allowed other hum reduction techniques (briefly alluded to in the video) such as lifting the cathode above ground, and/or "biasing up" the AC heater supply with a small DC voltage. This also provided more circuit design options for injecting feedback or improving circuit linearity, especially for drivers and phase splitters. Factor in the addition of screen grids that allowed for lower internal capacitance and more stable operation, and the design options increased by leaps and bounds.
Tubes with independently heated cathodes also warm up more slowly than the filaments of indirectly- heated tubes, and are better insulated against arcing; this is why a 5AR4 (GZ34) is a more desirable rectifier tube for power supplies because it doesn't shock the filter caps and the other tubes with nearly immediate high voltage like a 5Y3 or 5U4 filament-type rectifier does; the 5AR4 also has less internal voltage drop under load due to the close spacing of the cathode and plate, providing improved efficiency (a filament rectifier requires greater spacing between elements to prevent arcing).
By the way, some of the very earliest tube types did not have "coated" filaments for providing emission, Tungsten filaments impregnated with Thorium were used in a few consumer-level "recieving" tubes (such as the WD11, IIRC, or was it the 199?), and Thorium-impregnated filaments were (are still?) often used in commercial transmitting tubes. Hot flash: when such tubes become weak, a brief period of running the filament at double or triple the normal voltage will bring fresh Thorium to the surface of the filament and restore operation. Unfortunately this doesn't apply to most "modern" tubes found in radios, hifi and guitar amps....
Wow. You are an awesome teacher.
Being born in 2001, this is the only educational material left on this. Honestly thankyou for doing such a great job on breaking everything down.
Those old school varicaps are works of art! That's actually what first got me into electronics, fiddling with the tuning on an old broken radio whilst peeping through the vents in the back and watching the varicaps move... I was pre-school and had no idea what I was looking at... but I really really wanted to find out.
Sir, this video you have shared with us is phenomenal. Your instruction demands an A++. Thank You for posting this. It is very informative.
I know it is an old TH-cam video but i was actually taught this in the Army in 1991. I was in an Air defense unit that still had 1 radar built in 1938 and it was a blast to work on. We used a slightly different book but do remember the same diagrams and taught the exact same way.
I remember as a young kid in the late 60s and early 70s you could still get the Popular Mechanics magazine that would give simple circuits to build and experiment with.
Good job Tom with the video brought back a lot of memories and the fun i had doing this. Makes me want to get back in it again on old radios again.
I am glad I found ur page Tom!
This sir is the best VT video i have seen since i started researching about the subject about a year ago, when i decided i would start restoring old am radios as a new retirement hobby. Your knowledge is just as impressive as your teaching and communication skills and i thank you for sharing all of this with us. Will start watching part 2 ASAP. Also dowloaded the manual which i can't wait to devour.
Be well, Go bless
Over the last few years, my interest in vacuum tube has increased, and it's videos like this that really help solidify my understanding of the basic of these fascinating devices.
Thank you so much for such a clear explanation.
it's like Mr wizard meets Winnie the Pooh ; ) -love this! Thank you sir
Proof that without nothing you can't have something.
This is splendid. Marconi/Osram Kinkless Tetrode : KT series. 66,77,88,120...150. 😊♥️
Ive only just discovered your channel,
what a fantastic well explained tutorial you have made here,
thank you this was just what i needed, i am about to embark on a journey into power transmission tubes for Tesla coil use & if ime honest my experience with small radio amplifier valves is utterly insufficient for what i am about to attempt.
I really needed to understand the principles better & look at how i should be utilising the connections,
i have a whopping great GU39-B & i am worried that i might ruin it by making errors,
there are more connections than i was expecting on it which has thrown me a little.
I have many years experience with solid state coils & sparc gap coils, but i have never attempted a tube coil or a coil capable of such scary power levels.
Dont worry ime also a radio fan & i am working in a fully caged environment with a protected off grid supply so i dont upset every radio operator with in 100 miles of me. Ime based in the UK
Tom, You made me feel like I was in college of the 40s and 50s, for the Radio Serviceman, and I was born in ’62. I have been doing vintage radio customer repairs as an electrician with 99% success rate over the past 6 years and always wished to have, far more understanding on more of the technical side and learn from the knowledge from someone like you. I have a 1930 full college text book and 5 volumes from 1950. The way you presented this tutorial was just amazing and appreciate the time and effort you spent doing this video. I think I have learned more in this video than I have in the text book. My hat off to you Sir 👍👍👍
One of the best classes I've taken! Thank you!!
Im 65.. fascinated by this stuff just delving into the nuts and bolts.. a guitar player interested in bulding amps .. and thank you so much for this info 👍👌🙏
I'm old enough to have been taught vacuum tube theory in school, and even having used them in projects around the same time (although the transistor was well established and getting cheaper by the day), and yet find that this lecture is one of the best I have watched on the subject. Good work!
It may have been interesting to mention why the beam tetrode even existed, since the regular tetrode problem had been solved so well by the pentode. The answer is, due to commercial interests. The pentode was patented, and as far as I understand it the patent license fees were fairly significant - so other manufacturers tried to get around having to pay the patent fees by building something that reasonably did the same thing as a pentode, without mechanically being a pentode (i.e. not having a suppressor grid). It worked reasonably well, but only at high power - you mentioned that it needs a lot of current to create the space charge that makes the virtual electrode/electron cloud that acts like the 3rd grid. At low powers, the pentode is still the king.
Also the tetrode with its kinked transfer characteristic has some applications in its own right; the more pronounced the negative resistance interval is, the better it functions as an oscillator.
One of the best videos on TH-cam, I grew up and got my electronics degree in the transistor age (just) and really appreciate the clear yet detailed explanation, it’s fascinating to learn how this stuff worked, I had no clue the difference between triode, tetrode and pentode and I always wondered why pentode when we get by just fine with 3 terminal semiconductor transistors even now,,well now I know the answer, thank you!
thank you very much for your precious explanations and book suggestion. Now I'll watch your next video on the subect
I have thoroughly enjoyed watch and learning from your video. I am trying to learn as much as I can about old vacuum valve radios. I have very limited electrical knowledge and appreciate the time and effort you have put into this tutorial
My dad tried to teach me about vacuum tubes, apparently he repaired t.v sets and radios when he was young, but I was in the cusp of dip integrated circuits. Basically my dad taught me that a vacuum tube is a " valve" . It just controls electrons from one point to another. Similar to a transistor. When he said transistor, I was in some understanding of how a tube works. This is very interesting. So, years later I'm experimenting with a device that I bought off an estate sale. This device uses two OD3a. tubes. I think it's a power supply, just not sure. Good video. Thank you.
My mom work at Cbs Hitrone.
She built them ,she left for bell labs to grow the first crystals that bell labs used to build them and transistor
Thanks for the great video Tom- a simple and well thought out explanation. Very much appreciated!
I love your teaching.
Very Generous of you to share your knowledge with us. My interest is mainly in Tube type Guitar Amplification - but your tutorial has helped me envision much better the elements, construction and operation of these fascinating devices. Very much appreciated. Thank you very much. I will watch more of your videos and tutorials. ~ Murph_
I finally understand how these tubes work! Thank you professor!
Couldn't follow a thing, this man definitely lost me at the start. But I still watched.
I really enjoyed this class. Thank you.
Yes, I have become interested in tubes lately.
OMG, you are an absolute treasure! As I hear more and more about the technical & basic engineering ideas that were taught in years past full confirms my hunch about the utter inadequacy of my 1980's & 90's education at the time I was getting it. I could do calculus all day long but it was meaningless & trapped in a void because apparently it was felt to be too dangerous (or too expensive?) to teach real world applications or the economy of the time assumed that I either needed to program computers or work in a bank. Thank you so very much for sharing this with us.
Very good explanation
Thanks 😊
Cheers
Great video! I grew up only 20 mins from Fort Monmouth. What a place.
Thank you for what you do!!!!!
Wow, you explain it so clearly. Just what I was looking for. Many thanks.
Most excellent presentation...!
Greetings, I want to refresh my knowledge on VT as I am wrkg on an old RCA Radiola60 and I am looking forward to this.
Bless you for this, without people like you, this part of the electronics world would surely die. i have enjoyed both videos on this. please continue, and you have a great teaching style.
Thank you for the plain-spoken explanation of tube principles.
Tom thanks for this amazing and inspiring lecture. You have the art of clear an calmly explain tubes theory. Thanks also for the pdf reference. Maestro! 👌🏾👌🏾👌🏾👌🏾
Funny, I have a similar story. My father, who was in the window business, told me to drop by his friend Emil's house to help me with a kit that was having trouble with. Emil worked for RCA Harrison vacuum tube division in NJ and it was he who taught me how a vacuum tube worked when I was only 15.
This is the exact video I needed. Thank you. :)
Note that the photos of Williamson amps at the end of the video, from Stancor transformer catalogs and so on, appear to be utilizing 807 tubes, a high-voltage variant of the 6L6 designed for ham radio transmitters, with an old-style 5 pin base and the plate connection on top of the tube (to deter arc-over, which might otherwise occur if the high-voltage was applied thru the base, near the other pins). Also interesting to look at the pronounced nonlinearity in the transfer curve of the 6J7, since that tube was often used for microphone preamps in the broadcast and recording industry!
Thank you for taking the time share some old school wisdom, I really appreciate it. I only use tubes for my guitar amps but it is nice to know a bit more about how they work in detail.
Thank you for your service to this Country and thank you for this outstanding Tutorial .
All my best.
Bobby
I believe these are referred to as thermionic devices.
In addition to thermionic emission, most ( not the dc voltage regulator) of the various applications involve the application of time varying voltage as part of some continuity scheme to complete the circuit via the thermionic element.
The solid state device version (p-n junction) is basically a drop-in replacement to the thermionic emission device and so eliminating the need for a heater from which the electron mobility is derived.
These continuity schemes carry over to circuits having solid state non-thermionic versions of the devices from which electron mobility is derived.
But in the solid state world both holes and electrons are referred to a charge carriers.
This is a great video that shows the application of vacuum tube technology in example circuits to achieve practical uses of vacuum tubes.
Amazing video. Simply amazing. Great job and thank you for sharing.
Great Video. Many thanks for sharing this piece of art.
73 from Brasil - PU2SRZ.
Thank you for a really excellent presentation.
This was a great Tutorial on Tubes.... I'm sure it was basic, but just what I needed. Thanks for posting!
very well made and informative video, thank you very much
now I'll need to get my hands on some tubes
Excellent tutorial, thanks!
Thanks for your knowledge, very interesting. Tubes something new for me because I work in the RF heat sealing industry where the machines date back to 1960. The technology is older than me but the machines may only have a few years on me.
Wow!!! Thank you!! You are a fountain of knowledge...I enjoyed this video and learned a lot!
As always great video. If your still doing them I'd like to see a show on output transformers including interweaving wraps
Hi Tom,, Just watched your great video on Tube operation,,, Loved every minute,, learned a great deal. Thank you for doing the lessons,, :)
Very well explained, thank you for the great explanation.
Delighted, Class A explanation!!
Thank you for your effort sir. This is great !
very educative. thank you.
Very interesting and informative. Thanks and regards from the UK.
Thank you for the great instruction
Very helpful. Thanks for posting.
i always wanted to tune the filiment with gold on a crt for specified detector usage thank you
Thanks a lot for your information shared,
Iliked this vdi 3 much.😀
Great video! Thank you much Sir!
My Radiola60 has centertapped resistors across the heater leads, the centertap goes to a
voltage divider and through the secondary coil and to a grid in the 71A amp tube. I am told I could have too much bias as the set oscilates a lot. If I am correct, taking part of the output to a tickler
coil I'd have an oscillator of the Hartley type being inductively coupled or if using a cap, a colpitts
oscillator. I had to know all this to get a ham radio ticket and learn morse code too. It was all
good, electronic physics.
Great video. I'm trying to get my jukebox amplifier going (it's 40 years older than me!) and the outlined information here is a treasure trove of information. I'll definitely be watching your other video tomorrow and downloading that technical manual. Thanks for putting this online!
If you cant get your Jukebox going without videos like this , you probably shouldn't do it , since Tube Amps are simplest form of Circuit , on a level of a Heater with some controls , you probably shouldn't do it , there are high voltages present , that can be more then nasty . . Non the less im interested , did you get it going or what , somehow i doubt it :)
Youre a good man, thank you
Nicely explained!
If my Electronics professor was like you then I would have gotten a better grade.
Thank you! Very informative
Very good presentation, keep them coming.
Fantastic!
Excellent, made much more sense for me than many other tutorials I have watched. I shall be checking out the rest of your content.
Greetings!! Love Your film. Wish You a lot of health and hope for more films from You!!
Ty sir this is exactly what I needed
excellent !
Very nice presentaion. Thank you sir.
Thank you!
Great videos
thanks, most informative
Great explanation
Very interesting, thanks.
Well done
Thats some tuning capacitor!
They stopped teaching tube stuff before I went to electronics school in 1987 but i remember similar diagrams for transistors.
always wait for the vacuum tube to cool down before pulling it out of the component, those puppies can get really hot. when you see lightening in a vacuum tube when you turn on the component, most likely the vacuum tube is not working right and is going into failure mode.
thank you so much
At minute 13:00, you seems to show current reversing in the load. You probably wanted to mean in the capacitor.
Variable-mu tube were also used in pro audio equipment for use in compressors.
Great Video ......... So can I assume that "bias" pertains only to grid current ? Is bias current always separate like the heater circuit?
Thanks, pl. explain the magic eye EM34 /or UM4 ,Ac/dc function.I will ever reman grateful to U.