Inventions Project: Triode (aka vacuum tube)

Foxworthy925 · #1 12-05-2008, 10:43 AM

Hey guys so here's my dilema. I'm in US history this year (junior in hs) and we've just been assigned a project about the American inventions that have "changed the world". The time period is 1870-1929, and I've chosen the triode. Part of the project is actually building some sort of model to present to the class. This part of the project is actually somewhat labor intensive (well he aspires for it to be), and the teacher isn't expecting anything short of excellence. Now, I know there are kits that would allow me to build my own tiny tube amplifier, but I highly doubt that I'll have the skill, time, and money to go frivolously buy and assemble a working tube amplifier by the end of next week. But at the same time, I would rather not resort to building a giant euphemised model of a vaccuum tube, and only be able to explain the parts and function. I really would love to be able to build a working tube circuit some how, but I'm not sure this is feasible given the small time frame. Any thoughts guys?

Foxworthy925 · #2 12-05-2008, 11:05 AM

Right, so I've done a little bit of research and I just need to clarify this, mostly for my own benefit. So when the triode was first invented, it didn't even really rely on a vacuum, or atleast, not like modern vacuum tubes. The first true "vacuum" tube was developed several years later by Irving langmuir in 1915. Alright, so I think I will be focusing on the true vacuum tube, developed by this man, rather than the earlier triode.

Georynn · #3 12-05-2008, 12:03 PM

Quote:

Originally Posted by Foxworthy925

Right, so I've done a little bit of research and I just need to clarify this, mostly for my own benefit. So when the triode was first invented, it didn't even really rely on a vacuum, or atleast, not like modern vacuum tubes. The first true "vacuum" tube was developed several years later by Irving langmuir in 1915. Alright, so I think I will be focusing on the true vacuum tube, developed by this man, rather than the earlier triode.

Find some old ham radio, I have a couple that are just beautiful when the tubes glow, a nice sound when warm...

Foxworthy925 · #4 12-07-2008, 10:14 AM

Ah now there's the thing. Another group in the class already chose the invention of the radio, so I'm really trying to stay away from that side of the pond and just focus on the invention of the "tube technology" itself. Thanks for the reply though.
I'm also really supposed to build/construct something, so that's another strike against finding an old radio..

Anyone else?

hbarcat · #5 12-07-2008, 12:00 PM

How about building a board that contains different types of tubes that you can then power up and have multimeters show how they work? You could include an early diode tube and then a triode, and also some other later types of tubes that you think would make an interesting contrast with the triode.

You could show how the different tubes handle input and output differently and use this as a stepping point for explaining how theory works toward application. Demonstrate how some tubes are used for rectification and some for preamps and some for power amps and so forth. Your teacher should eat that up.

Rody · #6 12-07-2008, 03:21 PM

Just remember: Tube voltages can kill!
Good luck!

Cheers Rody

vene-nemesis · #7 12-07-2008, 05:01 PM

Dude why did you choose such a hard project??????? I mean during that period you had a lot more choices than that:

Many john browning guns that were great advances like the 1911 45cal or the 9mm.
The freaking model T you could even build a small PVC engine to show how a inner combustion engine works.

Stumbo · #8 12-07-2008, 05:07 PM

Quote:

Originally Posted by vene-nemesis

Dude why did you choose such a hard project??????? I mean during that period you had a lot more choices than that:

How about the telephone by A. Bell?

vene-nemesis · #9 12-07-2008, 05:18 PM

Quote:

Originally Posted by Stumbo

How about the telephone by A. Bell?

I believe its been questioned if he did invented it.

Foxworthy925 · #10 12-10-2008, 01:55 PM

Hey thanks for the help guys. Any others?

i_got_a_mohawk · #11 12-10-2008, 02:33 PM

Quote:

Originally Posted by vene-nemesis

I believe its been questioned if he did invented it.

Not to mention that he wasn't American.

MakiSupaStar · #12 12-10-2008, 02:34 PM

You dumb. You'd be better off doing a report on cold fusion.

Foxworthy925 · #13 12-10-2008, 05:14 PM

Hey guys, does anyone know if it would be possible for me to build a simple tube circuit? Nothing that actually serves a useful function. Just a circuit incorporating like one 12ax7 so that the tube can warm up and just flow a current. Would that be possible, and any ideas?

vene-nemesis · #14 12-10-2008, 05:24 PM

yes it is, i thought that somehow you were attempting to build the tube. BTW i suggest you make a black enclusure to put the tubes so when they light up it is easier to see it without turning off the lights.

Foxworthy925 · #15 12-10-2008, 05:30 PM

Well damn, that would be amazing. ... I just don't know how. Could you give me a link to anywhere with instructions or schematics? Or could you tell me? It would be greatly appreciated. I'm not sure where to begin.

Foxworthy925 · #16 12-10-2008, 07:39 PM

Anyone?

IanStephenson · #17 12-11-2008, 04:50 AM

http://www.radau5.ch/basics_1.html

I've never worked with tubes, but it should be pretty easy (assuming basic access to tools, and school lab equipment) to set up a single tube with just appropriate biasing, heating so you can feed in an AC signal from a signal generator, and show the input and output on an oscilloscope (demonstrating you've got gain which is basically the whole point). Anything more is ambitious in a couple of days without previous experience.