Vacuum Triodes
Chris Cristini, Sun Jan 20 2019, 07:48PMIf we could make Triodes with today's manufacturing techniques would they be worth anything other than Vttc?
Re: Vacuum Triodes
hen918, Sun Jan 20 2019, 10:11PM
I'm not sure about triodes specifically, but vacuum tubes/valves are still used in large high power radio transmitters. For dealing with a few hundred kW in the MHz, they work pretty well.
hen918, Sun Jan 20 2019, 10:11PM
I'm not sure about triodes specifically, but vacuum tubes/valves are still used in large high power radio transmitters. For dealing with a few hundred kW in the MHz, they work pretty well.
Re: Vacuum Triodes
2Spoons, Mon Jan 21 2019, 07:46PM
There's a lot of love for vacuum tubes in the audio world.
2Spoons, Mon Jan 21 2019, 07:46PM
There's a lot of love for vacuum tubes in the audio world.
Re: Vacuum Triodes
the_anomaly, Mon Jan 21 2019, 11:17PM
What improvements would today's manufacturing techniques bring? Tube performance? Longevity? Cost to Manufacture? I second the audio group as a strong interest.
the_anomaly, Mon Jan 21 2019, 11:17PM
What improvements would today's manufacturing techniques bring? Tube performance? Longevity? Cost to Manufacture? I second the audio group as a strong interest.
Re: Vacuum Triodes
Proud Mary, Wed Jan 23 2019, 11:57PM
The Russians continued producing new thermionic valve designs long after development had all but stopped in the West, which lead to the production of some excellent miniature and sub-miniature valves.
Thermionic valves are much more tolerant of EMP and radiation than semiconductors, and some Russian miniature valve data I have seen includes high G force operation, suggesting their use in missiles, but I am only speculating.
You can make yourself an excellent little triode super-regenerative radio receiver, with a sensitivity of a few microvolts, great fun and sensitive enough to pull in a good range of short wave and VHF signals.
Proud Mary, Wed Jan 23 2019, 11:57PM
The Russians continued producing new thermionic valve designs long after development had all but stopped in the West, which lead to the production of some excellent miniature and sub-miniature valves.
Thermionic valves are much more tolerant of EMP and radiation than semiconductors, and some Russian miniature valve data I have seen includes high G force operation, suggesting their use in missiles, but I am only speculating.
You can make yourself an excellent little triode super-regenerative radio receiver, with a sensitivity of a few microvolts, great fun and sensitive enough to pull in a good range of short wave and VHF signals.
Re: Vacuum Triodes
Chris Cristini, Thu Jan 24 2019, 03:33PM
I was just thinking Tubes are much easier to develop something new/improve VS semicondors.
I mean just the simplicity is awesome maybe even try a different approach to Electron flow vs Heating elements. Maybe laser to heat a thin Metal plate at 2W vs 40ish? It could be like the IGBT where you have the robustness of a transistor and the ease of driving like a Mosfet.
Chris Cristini, Thu Jan 24 2019, 03:33PM
I was just thinking Tubes are much easier to develop something new/improve VS semicondors.
I mean just the simplicity is awesome maybe even try a different approach to Electron flow vs Heating elements. Maybe laser to heat a thin Metal plate at 2W vs 40ish? It could be like the IGBT where you have the robustness of a transistor and the ease of driving like a Mosfet.
Re: Vacuum Triodes
Chris Cristini, Sat Jan 26 2019, 04:41AM
Sorry that was a tired post didn't make to much sense my question is basically can there be efficiency improvements? I did a bunch on research and its not promising. :)
Chris Cristini, Sat Jan 26 2019, 04:41AM
Sorry that was a tired post didn't make to much sense my question is basically can there be efficiency improvements? I did a bunch on research and its not promising. :)
Re: Vacuum Triodes
radiotech, Sat Jan 26 2019, 08:46AM
Vacuum tube development in the past advanced as a result of specific needs
that arose. For different and more efficient processes for manufacture, first describe
a need, and it will be met.
As to lasers heating thermionic cathodes, some vacuum tubes do not need heaters.
Their cathodes develop a space cloud when an ionized gas pulls electrons off and heats it.
An example is the 0Z4 tube, and 'instant start' fluorescent lamps.
radiotech, Sat Jan 26 2019, 08:46AM
Vacuum tube development in the past advanced as a result of specific needs
that arose. For different and more efficient processes for manufacture, first describe
a need, and it will be met.
As to lasers heating thermionic cathodes, some vacuum tubes do not need heaters.
Their cathodes develop a space cloud when an ionized gas pulls electrons off and heats it.
An example is the 0Z4 tube, and 'instant start' fluorescent lamps.
Re: Vacuum Triodes
Conundrum, Sat Jan 26 2019, 03:24PM
Wonder if it's possible to make a vacuum tube single chip computer? Using nano thermonics
Conundrum, Sat Jan 26 2019, 03:24PM
Wonder if it's possible to make a vacuum tube single chip computer? Using nano thermonics
Re: Vacuum Triodes
Proud Mary, Sun Jan 27 2019, 02:12PM
The Nuvistor series of triodes and tetrodes introduced by RCA in 1959 were metal and ceramic thermionic valves smaller than a thimble. They are excellent low noise performers (by valve standards) and the very small interelectrode spacing makes them good performers up into the UHF.
Proud Mary, Sun Jan 27 2019, 02:12PM
The Nuvistor series of triodes and tetrodes introduced by RCA in 1959 were metal and ceramic thermionic valves smaller than a thimble. They are excellent low noise performers (by valve standards) and the very small interelectrode spacing makes them good performers up into the UHF.
Re: Vacuum Triodes
Conundrum, Sun Jan 27 2019, 02:41PM
Seem to recall selling a bunch on ebay.
Conundrum, Sun Jan 27 2019, 02:41PM
Seem to recall selling a bunch on ebay.
Re: Vacuum Triodes
Patrick, Sun Jan 27 2019, 09:26PM
hybrid vacuum / semiconductor CPUs have been attempted. Havent heard much since the early 2000's.
Patrick, Sun Jan 27 2019, 09:26PM
Conundrum wrote ...
Wonder if it's possible to make a vacuum tube single chip computer? Using nano thermonics
Wonder if it's possible to make a vacuum tube single chip computer? Using nano thermonics
hybrid vacuum / semiconductor CPUs have been attempted. Havent heard much since the early 2000's.
Re: Vacuum Triodes
johnf, Mon Jan 28 2019, 06:59PM
We made some field emitting diodes and triodes @ work
Due to the extremely small size we could run them at atmospheric pressure because the mean free path between anode and cathode was small enough to exclude air molecules.
johnf, Mon Jan 28 2019, 06:59PM
We made some field emitting diodes and triodes @ work
Due to the extremely small size we could run them at atmospheric pressure because the mean free path between anode and cathode was small enough to exclude air molecules.
Re: Vacuum Triodes
radiotech, Wed Jan 30 2019, 08:20AM
I have replaced Nuvistors in my TV service days. The little beggars can cut your
fingers !
radiotech, Wed Jan 30 2019, 08:20AM
I have replaced Nuvistors in my TV service days. The little beggars can cut your
fingers !
Re: Vacuum Triodes
Mattski, Mon Apr 29 2019, 08:40PM
There's ongoing work with microfabrication to create vacuum TWTA amplifiers to operation in the 100's of GHz. Improved cathode materials are also needed for that to increase the power density I understand, which could potentially increase power densities at lower frequencies too then.
But even companies that were more focused on vacuum device amplifiers have had to add solid-state amplifiers to their lineup to remain competitive. Vacuum tubes have niches where they are the best technology today, but solid state is often the better solution today, either higher performance or lower cost or both.
Mattski, Mon Apr 29 2019, 08:40PM
There's ongoing work with microfabrication to create vacuum TWTA amplifiers to operation in the 100's of GHz. Improved cathode materials are also needed for that to increase the power density I understand, which could potentially increase power densities at lower frequencies too then.
But even companies that were more focused on vacuum device amplifiers have had to add solid-state amplifiers to their lineup to remain competitive. Vacuum tubes have niches where they are the best technology today, but solid state is often the better solution today, either higher performance or lower cost or both.
Re: Vacuum Triodes
Ash Small, Thu Jul 04 2019, 10:50PM
I've been looking at state of the art SiC power JFET's..... Some are good for 40A or more, and good for 1.2kV.... United Silicon Carbide produce them, and I think it's Mouser that supplies them..... In many cases they should pretty much be a direct replacement for a triode operating in class 1 (negatively biased grid), although I'm experimenting at lower voltages, with low impedence, high Q factor circuits..... There internal resistances are fractions of an Ohm....
Ash Small, Thu Jul 04 2019, 10:50PM
I've been looking at state of the art SiC power JFET's..... Some are good for 40A or more, and good for 1.2kV.... United Silicon Carbide produce them, and I think it's Mouser that supplies them..... In many cases they should pretty much be a direct replacement for a triode operating in class 1 (negatively biased grid), although I'm experimenting at lower voltages, with low impedence, high Q factor circuits..... There internal resistances are fractions of an Ohm....
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