Diodes vs. Triodes

Also, some tubes can be used for stuff they were not designed for - a triode with the grid unconnected (or connected to another element?) can be used as a diode, though I can't wonder why someone would do that. Also, things like Pentodes can be run as triodes (resistor between a couple of the grids).

In Simple terms: Diode = rectifier, used in power supply.
Triode = amplifier, used in gain stages.

-Ed

I. General-Introductory articles. All of these will help answer your question. #4 might be it if you only want to read one short article.

1) ✔ A Taste of Tubes:
http://www.anthemav.com/OldSitev1/frames/tubesfr.html
2) ✔Articles Section, The National Valve Museum.
http://www.r-type.org/static/.contents.htm
3) The Cool Sound of Tubes:
http://www.spectrum.ieee.org/select/0898/tube.html
4) How A Vacuum Tube Works:
http://www.svetlana.com/docs/tubeworks.html
5) Vacuum Tube Valley FAXs:
http://www.vacuumtube.com/FAQ1.htm
6) Vacuum Tube FAX:
http://home.earthlink.net/~busenitz/vac.html
7) A History of Tube Companies:
http://vintagetubeservices.com/page8.html

If you want one step more read this

✔ Ray Dall, Electronics Theory.com
http://www.electronicstheory.com/html/e101-37.htm
Some basics on circuits about as briefly as is possible. About 50 pages. An overview of how a tube works begins on page 37.

This comes from an outline of online tube articles I have put together. It is geared at the DIY crowd but has other stuff to. If anyone wants a copy drop me an email.

I remain,

Did anyone mentioned that Diode can be semiconductor of a type p or n? Not only tube!