View Full Version : Flame Triode
N0WVA
03-20-2008, 02:40 AM
Ive often wondered if other devices besides tubes and transistors could be made to amplify at high frequencies. I guess this answers my question:
http://www.sparkbangbuzz.com/flame-amp/flameamp.htm
I wonder just how high in frequency this would oscillate?
It's the same principle as a vacuum tube, really.
Pretty fascinating though.
ka5piu
03-20-2008, 02:40 PM
Hello.
Zinc can amplify.
http://home.earthlink.net/~lenyr/znrfamp2.htm
But, the very first tube, the audion, can be had, a fleming valve with a grid, and that is just a light bulb with a plate.
http://www.ferrowatt.com/
http://www.sparkmuseum.com/FLEMING.HTM
http://earlyradiohistory.us/audi1907.htm
I have a pair of ferrowatt light bulbs running thru a diode, on a polished wooden box, for that early era effect.
All wiring is under covers for safety, and there is a metal chassis under the wood, but the effect is stunning.
kl7aj
03-20-2008, 02:55 PM
It's the same principle as a vacuum tube, really.
Pretty fascinating though.
It certainly is. We played around with this sort of thing in the UCLA plasma lab. By the way, a candle flame is also conductive. And you can also wobble it with electrostatic plates and an audio ampfier. :)
eric
Tunnel diodes can be made into oscillators and regen receivers...and likely amplifiers..and work up to the 10s of GHz ranges - 30-40+ GHz. THey were in use in the 60s.....before GaAs devices and technology came about. YOu still have things like IMPATT diodes used in military equipment.
The first 'vacuum tubes' were a soft vacuum. Had residiual air in the envelope. The did not have good vacuum pumps. Early triodes had a gain of 5.
It took a long time to understand the 'space charge' principle and 3/2 law for hard vacuum tubes. After 10 years, others got better vacuum pumps, and real vacuum tubes started to be built.
The first Audions (triodes) were cantakerous....didn't work well...had to 'rest' between periods of use to recover (from the filament having gotten contaminated by the residual gas)......and didn't last long.
After 10 years of development, hard vacuum tubes in the 1920s worked well. Adding thorium for the filament cut down current requirements by 80% for the filament. Once they went to indirectly heated cathodes, even better. Then they put extra grids in ...and radios were off to the races.
K8ERV
03-20-2008, 05:03 PM
you can also wobble it with electrostatic plates and an audio ampfier. :)
eric
I gotta try that!!
TOM K8ERV Montrose Colo
ab9lz
03-20-2008, 05:05 PM
Pretty cool stuff, he get also gets huge brownie points for running an old Tektronix :)
73 m/4
kl7aj
03-20-2008, 09:26 PM
I gotta try that!!
TOM K8ERV Montrose Colo
You want to have the plates actually in contact with the flame. And you will want a couple hundred volts. If you have a filament transformer, or even a couple of them in cascade, and run them from a ten watt or so audio amp, it will work (You know the plates are in the sweet spot if you measure about 20k between them with a DVM.
eric