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I was just checking how Vacuum Tubes worked in this very informative video Principles of Vacuum Tubes, however I was unable to understand what is the third point i.e Vacuum Tubes as "Generators".

Is it the same as https://en.wikipedia.org/wiki/Electronic_oscillator?

Most modern books don't explain legacy technologies like Vacuum Tube because it is out-of-date and Transistor has the same principles. From my experience which is not necessarily applicable to everyone, I felt that for a beginner being introduced to this field, explanation with simpler devices is usually more easier to grasp and it also gives you the motivation for finding Transistor and why it was such a path breaking invention.

Are there any books which deals with legacy technologies like Vacuum Tubes etc?

Retaining some parts of original question which was quoted in the answer.

Would books like "The Art Of Electronics" help me study these topics in a more organized manner?

Nishant
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    Think of them as JFETs that use high voltage. – Ignacio Vazquez-Abrams Sep 23 '16 at 05:46
  • Thank you I will google up on that. TBH, I don't know JFET's etc, I am trying to understand this as a Web Application programmer like from very basics :) I guess these are Electronic Oscillators right? – Nishant Sep 23 '16 at 05:48
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    *I guess these are Electronic Oscillators right* JFETs ? No, they're not oscillators. They're a sort of transistors that work a bit like a resistor which value can be influenced by the voltage on a third control pin (the gate). As a beginner you can forget about JFETs for now, they're not that useful and not used that often. – Bimpelrekkie Sep 23 '16 at 07:38
  • Is there a reason for the down-vote. Is this a bad question to ask? I thought its within scope. Please let me know if you have a reason for down-vote so that I can ask accordingly. – Nishant Sep 23 '16 at 08:37
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    I'm voting to close based on the question being too broad and open ended. Also, it solicits opinions (opinions are not answers so read the good question guidelines again) and it's title asks for 6 purposes (as if there were only 6!). Asking for any good book recommendations is also frowned upon because it becomes a shopping question - now go back and read the damn rules again! – Andy aka Sep 23 '16 at 08:43
  • I was really looking for any books that might teach topics which involved old and possibly simpler technologies giving some historical perspective as well. However, I will read the guidelines and form better questions in future. – Nishant Sep 23 '16 at 09:00
  • @Nishant did you check out any other questions before posting? This question has already been asked http://electronics.stackexchange.com/questions/616/basic-electronics-book The reason for the downvote is because opinion based questions are not allowed. – Voltage Spike Sep 23 '16 at 19:50
  • Yeah I did favorite that post and went through some references which are mostly from Transistor. I keep getting doubts like why is Hole positively charged, it is just a lack of electron. I felt modeling these things really needs some deeper understanding. So I went into looking up Vacuum Tube resources etc and any books that just deals with some technology that has lesser abstractions. I will revisit this page on depth. – Nishant Sep 23 '16 at 23:13
  • Hello, was my original question open ended? If not, I can modify the book question so that doesn't sound like a regular book question. I think http://tubebooks.org/technical_books_online.htm really summarizes what I need. I hope such posts helps people learn and also get a historical perspective of things which I feel is important. My reasoning was that Vaccum Tubes existed before Semiconductors because it was a simpler idea to conceive and hence my interest in reading up old resources. Ofcourse these things won't matter later on when you have learned the concept but still its good to know. – Nishant Sep 28 '16 at 05:01

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Yes HF generators used high power valves in a linear mode to create high current RF generators for tin plating, AM radios in the multi kW range, Now they are megawatt generators for radio AM and FM radio. This genration uses high DC bias current in high voltage oscillators that resonate the load from DC to convert to RF AC with about 50% efficiency or less. A microwave oven today uses a 1-2kW Magnetron tube for generation of power. https://en.m.wikipedia.org/wiki/Cavity_magnetron

Tony Stewart EE75
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I was unable to understand what is the third point i.e Vacuum Tubes as "Generators".

Is it the same as https://en.wikipedia.org/wiki/Electronic_oscillator?

Yes. The section of the video describing the ability of the vacuum tube to "generate" uses a diagram of what appears to be an LC oscillator. Combined with its discussion of radio, it seems quite clear that they're referring to oscillators.

Would books like "The Art Of Electronics" help me study these topics in a more organized manner?

No. The Art of Electronics doesn't cover vacuum tubes in any detail, as they have essentially no purpose in modern hardware design. Outside of certain very specialized applications, silicon-based technologies (silicon diodes, transistors, FETs, etc.) have entirely replaced vacuum tubes.

Vacuum tubes are not any easier to understand than transistors; if anything, they are more complex. Unless you specifically plan on working with vacuum tubes, there is no point in trying to understand how they work.

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    *au contraire*, when trying to understand a tube, it's all out there in the open, the geometry. In comparing a vacuum tube triode to a JFET triode ... the boiling off of electrons, their acceleration to the anode, the control of space charge by the grid, so much easier than Fermi diagrams of conduction bands. Because it's 'only'geometry, it was possible for companies to study and then make exact equivalents/copies of other valves, something that's not always possible with semiconductors. Can't 'bring back the tube', just sayin. – Neil_UK Sep 23 '16 at 06:38
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    Valves are still manufactured and used, particularly in audio applications. There is also a lively hobbyist community repairing and modding old radios, televisions etc. It isn't a dead technology, even if it's now a minority technology. This forum http://www.vintage-radio.net/forum/ is full of people discussing these circuits, and I also recommend the YouTube channel "Mr Carlson's Lab". – Ian Bland Sep 23 '16 at 07:54
  • @Neil_UK Precisely that was the point I had in mind. Its all out there in the geometry. Understanding semiconductors really well needs knowledge Quantum Theory IMHO. – Nishant Sep 23 '16 at 08:40
  • @Neil_UK: "Because it's 'only' geometry, it was possible for companies to study and then make exact equivalents/copies of other valves, something that's not always possible with semiconductors." Yeah I think this is a *very* *very* important point. Semiconductors is not really an easy black box as it is made out to be IMHO. – Nishant Sep 23 '16 at 11:30
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    A transistor is more like a layer cake, a vacuum tube like a gingerbread house. Both bring their own challenges in manufacturing and materials science... – rackandboneman Mar 15 '17 at 13:49
  • @rackandboneman Yours is a magnificent analogy. The house is empty but the space has meaning. The cake is hard to examine with an excavator but production line layer cakes are very repeatable and compact and small changes in ingredients can make it flop. – KalleMP Apr 30 '17 at 13:10
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Yes, "generator" and "oscillator" mean the same thing in this context. You can make an oscillator with almost ANY kind of active device like a tube or any kind of transistor or integrated circuit. It is not as complex as you seem to think.

The fundamentals of oscillator design are basically the same whether you are using a transistor or a tube. It is not clear why you think that studying vacuum tube oscillators is important here in the 21st century?

Richard Crowley
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    I am trying to generalize and understand the Input Output of these devices regardless of the technology used. Transistors are very small devices and understanding the internals seems complicated. It won't matter to Electrical Engineers but it seems like a black box device to me needing Quantum Physics explanations. So, I wanted to know what Technology existed before Transistors, and what problems they solved. I felt that would give me a more simplified explanation of the requirements and the importance of Transistors and possibly an insight into replacements we find in future. – Nishant Sep 23 '16 at 06:15
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    Tubes "solved the problem" of having NO active components at all. There was essentially NO "electronics" before tubes. For all practical purposes, there is nothing about the operation of tubes that will help you understand transistors. Auto mechanics don't learn anything about the care and feeding of horses because we've moved on and its a waste of time and irrelevant. – Richard Crowley Sep 23 '16 at 07:25
  • Agreed. My interest is more because I find learning with Vacuum Tubes easier so far (see the geometry comment from @Neil_UK above). For example saying that there is a Grid and visualizing that it can cause amplification is more easier to understand than understanding the whole NPN junction with two depletion regions, the electric fields that exists in those regions, and then the reasoning why electrons are pulled to there. Understanding two types of carriers is also slightly concept for me. However that could change when I learn more. – Nishant Sep 23 '16 at 08:53
  • @RichardCrowley most car people do need to have a tiny grasp of horsepower to select a car. – KalleMP Apr 30 '17 at 13:15
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Electronic switching, digital logic, amplifiers and oscillators were build using vacuum tubes only when the movie was produced. But this was long ago when no transistors were available. Nowadays we use vacuum tubes only when the problem could not be solved using semiconductors. The magnetrons used in microwave ovens are an example, a solution using semiconductors only would be possible now but is much more expensive. Another example is the Travelling Wave Tube for amplification of frequencies between 0.3 to 50 GHz. Above 10 GHz they are superior to semiconductor amplifiers. Their efficiency of up to 70 % is not possible using semiconductors only, they reach only up to 30 %. The communication with satellites is still done using travelling wave tubes. There are also Klystrons for microwave power generation. Have a look to wikipedia, there are very good articles about magnetrons, klystrons and travelling wave tubes.

Decades ago, electronic computers were build using vacuum tubes only, but they were large and heavy, the reliability was low, they produced a lot of heat and needed a lot of energy. They needed a lot of repair, they were very, very slow compared with modern microprozessors and their price was huge.

Uwe
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  • This was a very gradual change - commercially made transistors were introduced in the mid-50's, vacuum tubes were still not uncommon in normal equipment manufactured in the mid-70's ... – rackandboneman Mar 15 '17 at 13:52
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Would books like "The Art Of Electronics" help me study these topics in a more organized manner? [...] Any good classical book recommendations will also be helpful.

As said, The "Horowitz" don't cover this argument, but there are some classic books that do it:

  1. "Electronic Devices & Circuits", Jacob Millman & Christos C. Halkias McGraw-Hill 1967
  2. The Radiotron Designer's Handbook, 4th ed. (1954 version or 1960 version)
  3. Principles of Electricity and Electronics Applied to Telephone and Telegraph Work, AT&T 1953
Antonio
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