Where does plate resistance reside?

[pjd3]

Oh no, I almost started a fight, I am the evil instigator - Kiddin.

But thank you for answering that question of mine. I did assume that the space between the plate and cathode was where the "plate resistance" lay, but was a little hungry for a deeper understanding in the physics of how that occurred. And sure, should the "plate resistance" change with operating point then that would highly suggest that it was far more than a plate material characteristic. (although I was amazed at how much Carbon Composition resistors value changes (increase) in real time as you solder them in - I actually decided to measure that a few nights ago while building up a Princeton Reverb amp fiber board).

Has anyone ever cracked open a tube and DCR'd the plates, cathodes and grids? I imagine they just measure a low resistance, under an ohm 'r something.

I'm certainly no physicist but, recall some years ago reading about a "electro-static field" that lies between two materials of differing electrical potential as what occurs in a capacitor (distance between the plates) - I had to wonder if that electro-static field was also the thing that "told the electrons where to go" in a vacuum tube. Just my loose head ramblings.

Thanks everyone for making this an interesting and insightful thread. I think I'm needing to go read it again,

Best,
Phil D.