[bob82274]

This is a question for my fellow EEs.  Are there any good websites that have small signal models of tubes?  Equations are expected.  I have spoke with several professors about this however they are more focused on how to make their CMOS transistors smaller .  Are there any pieces of literature that are worth looking at?

I have taken a quick glance at several circuits involving tubes and understand their basic nature as a triode in relation to a BJT or a FET but I would like a more in depth look the device physics.

Thanks

[Occam]

http://www.angelfire.com/electronic/funwithtubes/Basics_04_Triodes.html

more sophisticated -
http://www.eecs.umich.edu/~mmccorq/tubes/simulation/simulation.html

[bob82274]

That stuff from Michigan is great! Thanks!  It looks like it will be at least a decent intro paper to read.  

My favorite quote: 'Clearly the analysis is trivial once it is understood.'  

Only in academia.

Do you know of any papers that have the theoretical definitions of Rp and Gm instead of the measured/data-sheet values?  

I may look into the references cited from the paper for more info as well.

Again very good stuff!

[Steve]

u = gm x rp
gm = u/rp
rp = u/gm

Gm = change in plate current/ change in grid to cathode voltage with constant plate to cathode voltage.

Plate resistance = change in plate to cathode voltage/ change in plate current with constant grid to cathode voltage.

u = change in plate to cathode voltage/ change in grid to cathode voltage with constant plate current.