Just stumbled on this:
A new vacuum tube which puts vacuum fluorescent display technology to practical use
Nutube, similar to a conventional vacuum tube, has an anode grid filament structure, and operates exactly as a triode vacuum tube. Also similar to a vacuum tube, it creates the same characteristic rich overtones. By applying their vacuum fluorescent display technology, Noritake Itron Corp., a Noritake Co. Ltd affiliated company, have devised a structure which achieves substantial power saving, miniaturization, and quality improvements when compared with a conventional vacuum tube.
Realising substantial power savings
By making the form smaller we have succeeded in making significant power savings requiring less than 2% of the electrical power of a conventional tube. This allows for efficient and simple battery operation.
Nutube is less than 30% of the size of a conventional vacuum tube.
Real vacuum tube sound
The real triode structure produces a warm, unique vacuum tube sound, delivering excellent linearity.
High reliability, long life
Made in Japan. 30,000 hours of continuous life expectancy
KORGSince its establishment in 1963, KORG INC. has always strived to manufacture epoch-making electronic musical instruments using innovative creativity and the company’s own extensive technological expertise. In 1975, KORG introduced the world’s first compact tuner with a needle meter and has marketed innovative products worldwide at the forefront of the musical instruments market. KORG synthesizers combine excellent sound quality and features and have earned the support of music fans and professional musicians everywhere. Today, KORG designs and develops a wide range of electronic musical instruments from synthesizers and tuners, to digital pianos, signal processors, digital recorders and other peripheral equipment.
And for no good reason I want one!!!
The first radios I made were made with vacuum tubes. I find the notion of a Raspberry Pi sized card with a vacuum tube radio on it curiously attractive ;-) Unknown is the ultimate frequency response of these tubes. They are intended for the audio market so might not have the needed MHz range.
The FAQ says it runs on 5 VDC to 80 VDC. Gallery of pictures showing products using it:
All this has me thinking that you could package many of these in one vacuum package (with ion blocking metalized dividers) and a common heater and make a “Vacuum Tube Integrated Circuit”…. God I want to make one! Just to make some head scratch inducing devices out of it ;-)
Now it’s got me wondering just how much you could miniaturize and still have decent performance out of a vacuum tube…
Looks like I’m not the only one wondering:
Could modern, nanoscale vacuum tubes replace transistors?
By Joel Hruska on June 7, 2016
The systems that Dr. Scherer and his research team are working on are nothing like classic vacuum tubes — according to the team, the structures are roughly 1,000x smaller than a human blood cell, which would make them 6-8nm. One problem with modern CPUs is that they suffer from significant amounts of electricity leakage — Scherer’s designs would use leakage current to flip states on purpose, thereby improving efficiency and overall performance.
One reason for this research is that Scherer thinks the microprocessor teams scaling below 10nm will encounter problems. The properties of silicon apparently change at that point, becoming both elastic and emitting light. “It’s a different material, and it gives you this different behavior,” Scherer told the New York Times.
Can tubes replace transistors?
Dr. Scherer isn’t trying to reinvent the transistor or replace the silicon economy. Boeing is funding his research due to its potential applications in space and aviation technologies, and silicon will obviously be the gold standard for everyone for years to come. It’s still interesting to consider the question: Could such a fundamentally different technology, shrunk to a microscopic scale, solve the problems of transistor scaling and performance?
The I-tripple-E IEEE has another POV:
23 Jun 2014 | 16:14 GMT
Introducing the Vacuum Transistor: A Device Made of Nothing
This curious mash-up of vacuum tube and MOSFET could one day replace traditional silicon
By Jin-Woo Han and Meyya Meyyappan
At the NASA Ames Research Center, we’ve been working for the past few years to develop vacuum-channel transistors. Our research is still at an early stage, but the prototypes we’ve constructed show that this novel device holds extraordinary promise. Vacuum-channel transistors could work 10 times as fast as ordinary silicon transistors and may eventually be able to operate at terahertz frequencies, which have long been beyond the reach of any solid-state device. And they are considerably more tolerant of heat and radiation. To understand why, it helps to know a bit about the construction and functioning of good old-fashioned vacuum tubes.
Notwithstanding these advantages, when considered purely as a medium for transporting charge, vacuum wins over semiconductors. Electrons propagate freely through the nothingness of a vacuum, whereas they suffer from collisions with the atoms in a solid (a process called crystal-lattice scattering). What’s more, a vacuum isn’t prone to the kind of radiation damage that plagues semiconductors, and it produces less noise and distortion than solid-state materials.
It is that “less noise and distortion” that has kept the Vacuum Tube alive in specialty audio gear. Turn a semiconductor amp up to full with no input, you hear a whoosing sound. “Cascade noise” as a few electrons “cascade” into noise. Do the same thing with a high end vacuum tube amp, you hear almost nothing. ( I’ve done it, though admittedly it was back in the late ’70s)
But after four decades of shrinking transistor dimensions, the oxide layer that insulates the gate electrode of a typical MOSFET is now only a few nanometers thick, and just a few tens of nanometers separate its source and drain. Conventional transistors really can’t get much smaller.
Then this very interesting bit of practical physics:
But vacuum-channel transistors don’t need a filament or hot cathode. If the device is made small enough, the electric field across it is sufficient to draw electrons from the source by a process known as field emission. Eliminating the power-sapping heating element reduces the area each device takes up on a chip and makes this new kind of transistor energy efficient.
Another weak point of tubes is that they must maintain a high vacuum, typically a thousandth or so of atmospheric pressure, to avoid collisions between electrons and gas molecules. Under such low pressure, the electric field causes positive ions generated from the residual gas in a tube to accelerate and bombard the cathode, creating sharp, nanometer-scale protrusions, which degrade and, ultimately, destroy it.
These long-standing problems of vacuum electronics aren’t insurmountable. What if the distance between cathode and anode were less than the average distance an electron travels before hitting a gas molecule, a distance known as the mean free path? Then you wouldn’t have to worry about collisions between electrons and gas molecules. For example, the mean free path of electrons in air under normal atmospheric pressure is about 200 nanometers, which on the scale of today’s transistors is pretty large. Use helium instead of air and the mean free path goes up to about 1 micrometer. That means an electron traveling across, say, a 100-nm gap bathed in helium would have only about a 10 percent probability of colliding with the gas. Make the gap smaller still and the chance of collision diminishes further.
But even with a low probability of hitting, many electrons are still going to collide with gas molecules. If the impact knocks a bound electron from the gas molecule, it will become a positively charged ion, which means that the electric field will send it flying toward the cathode. Under the bombardment of all those positive ions, cathodes degrade. So you really want to avoid this as much as possible.
Fortunately, if you keep the voltage low, the electrons will never acquire enough energy to ionize helium. So if the dimensions of the vacuum transistor are substantially smaller than the mean free path of electrons (which is not hard to arrange), and the working voltage is low enough (not difficult either), the device can operate just fine at atmospheric pressure. That is, you don’t, in fact, need to maintain any sort of vacuum at all for what is nominally a miniaturized piece of “vacuum” electronics!
Oh my… I think I feel a whole new “everything old is new again” moment happening ;-)