460GHz Vacuum Transistor

For audio it would sound like someone talking after they inhalied some helium. I guess that's called the "Donald Duck" sound..... :)

Reply to
oldschool
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But that tube amp distortion is an attribute, and I'm so sorry I added that throw away line about "sound like original tube amps".

Mikek

Reply to
amdx

For guitars, sure. For "music", no way.

Reply to
krw

Didn't someone post a link to a smartass who turned a VFD into an amplifier last time these things came up?

Mark L. Fergerson

Reply to
alien8752

VFDs have heated filament cathodes.

Once upon a time, field-emission displays were the next big thing.

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John Larkin         Highland Technology, Inc 

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John Larkin

commercial product:

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Reply to
Jasen Betts

There are probably like 500 different amps, effects pedals, rackmounts, and sequencer plug-ins that do that. Line 6 being probably the most well known company:

Reply to
bitrex

Atom probes use pulsed voltages around 2kV. What you are talking about is completely different from the IEEE article.

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Did you read the article? They use 10 volts and think they can reduce it to around 1-2 volts. They also can operate at atmospheric pressure using helium. The voltage is too low to ionize the gas, so there is no risk of damage from ion bombardment. See

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Reply to
Steve Wilson

On a sunny day (Thu, 2 Nov 2017 15:21:30 -0700 (PDT)) it happened " snipped-for-privacy@bid.nes" wrote in :

Yes, Orion was a bit much actually, but NASA is just a part of US job creation, nothing to do with space. On top of that it is forbidden to find any sign of life outside earth for political and religious reasons, as NASA is basically a political organization with a large religious agenda controlling it.

Remember Dr Levin's test for life on Mars was positive, I remember the announcement,

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CONTRADICTED hours later ... Dark voice, NO THAT EXPERIMENT IS WRONG Well if it was so wrong and you knew that in a few hours, then why send it up there?

Just imagine earth would not be 4000 years old, and life was everywhere and not even Christian. I would have thought it would be a motivator for an other crusade :-) (by some Pieceful Pope)

Anyways, they (politicians) ordered the Apollo designs destroyed, ordered an end to all nuclear propulsion experiments, invented the space shuttle as an endless around the block job creator (for their voters), and by now need a Russian taxi to get just a few hundred miles up.. I expect E Musk's Mars mission to also get head wind from this government, as No Extraterrestrial Life Shall Be Found.

Mars from ESA in _true color_:

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Enlarged, without any color processing, try it yourself

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From my website:

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In the mean time 'they' are coming with a huge 400 meter long spaceship to check us out:

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Well, could be a normal asteroid too of course... :-)

Human beings, humming beans, apes, and what's the difference.

From a logical perspective I think that China does not have that barrier against extraterrestrial life, and has the best chance for a Mars colony. They just move forward.

Reply to
Jan Panteltje

On a sunny day (Fri, 03 Nov 2017 06:24:47 GMT) it happened Steve Wilson wrote in :

Well it is a prototype radiaton detector, look up GM tube. Last thing you want in space.

And why 460 GHz? what is next? light? I have an UV LED flashlight to veryfy US dollars are false, how many GHz is that?

Reply to
Jan Panteltje

Yes, I should have qualified that, glad you did. Mikek

Reply to
amdx

Well, you only need operating current greater than the average ionization leakage.

And it's probably less sensitive to radiation upsets because of the lower density of the operating medium. Substrate would matter, but substrate can be insulating, which helps greatly (e.g., SOI).

About 500,000.

Tim

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Reply to
Tim Williams

Like this:

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That's -2 KV peak, which rides on a DC bias in the 8KV ballpark. I managed to get the state of the art up from 10 Hz pulse rate up to 100 KHz, with a water-cooled DSRD pulse generator.

What you are talking about is

What all these things have in common is that the emitting tip erodes. In the atom probe, that's a feature. In the other cases, it's a fatality.

Let me know when it's in stock at Digikey.

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Reply to
John Larkin

olid state guitar amp that does this well I am unaware of it. I am open to suggestions, if anybody has any, as my life would be simpler if I didn't n eed to maintain and lug around tube amps.

Thanks for the suggestion. I am aware of the various Line 6 attempts, they just don't do it for me. I am willing to accept that I can't set them up correctly, my ears are broke, or I am just crazy, but I just can't make mys elf happy with the sound and dynamics at high gain.

Reply to
DemonicTubes

What causes erosion in a device running at 10 volts when there is no ionization impact?

I'm assuming it runs at low enough current to avoid melting the collector and to avoid electromigration.

Reply to
Steve Wilson

The same thing that has ruined every other field-effect emitter for the last 40 years or so?

This is just press-release nonsense. You could post a hundred such breakthroughs a day here. Review the last thousand or so and see how many became real.

What use is a 2 volt, nanoampere fet?

I'll get some from Digikey and try them.

Another uselessness factor.

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Reply to
John Larkin

What causes the erosion? Is it the high voltage used?

I'm not trying to prove you wrong. I'm trying to understand what the mechanism is in case it has any bearing on some of my other projects.

As I stated earlier, I could find no reference to tip erosion except that caused by ion impact damage or operation at high voltage. There was nothing on tip erosion at low voltages.

Reply to
Steve Wilson

For background information, I have a project that uses 40 nm emitters in normal atmosphere with large swings in temperature and relative humidity. I have been concerned about ozone generation and tip erosion from the beginning, which would require replacement of the electrodes and some way to destroy the ozone.

The IEEE article gives some hope that a lower voltage would still emit the electrons I need, but greatly reduce tip erosion and ozone.

The obvious solution is to try it, but this would require redesigning the structure to take advantage of a different mechanism than I envisioned at the beginning. I will probably do this anyway.

If you can give a mechanism for tip erosion at low voltage, it would be very helpful for this project.

Reply to
Steve Wilson

What's the physics at work, anyway?

One would suppose the required voltage is proportional to the binding energy and/or work function of the material, and so tungsten would be the best. But those are infinite and ideal properties.

One needs to take into account the boundary conditions, which are quite significant in an atomic-scale point. The band structure will be very different in that region (annular confinement modes, where the band splits into discrete levels spaced according to the dimensions of the tip?), and maybe that leads to weakening of the material (a zone of low electron density acting as a stress raiser?). One would then suppose, there exists an ideal tip shape which maximizes its minimum binding energy, while minimizing the work function or electron tunneling probability. Maybe it's a surface of rotation, with a funny curved profile; maybe it's not round, but polygonal; maybe it's a stepped cylinder, or pyramid or cone; maybe it's even hollow, or filled with other elements!

Would be interesting to see some analysis of this ... but wouldn't be so interested as to dare attempt it myself. :-x

Tim

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Reply to
Tim Williams

Wikipedia has a long article on field emission:

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It does not discuss tip erosion. A few articles I found say the electric field exceeds the binding energy of the atom, so it separates from the tip.

This means that high voltage and a sharp tip are needed. This has been my biggest problem from the beginning, since I thought I needed high voltage for electron emission, but I worried it would cause tip erosion and ozone generation. However, if I can get sufficient electron emission at low voltage as described in the IEEE article, that should reduce tip erosion and ozone generation. I'm going to give it a try.

Reply to
Steve Wilson

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