AC by-pass cap

[C Moore]

http://www.webphix.com/schematic%20heav ... _schem.pdf

In the simple schem above for example....
Can somebody give me a real rudimentary explanation of how this works.? It has always been a mystery to me.
From the input jack.....As the AC guitar signal enters the grid, it swings through a positive and negative wave. More negative causes less current across the cat resistor, a more positive wave cause more current across the cat resistor. Is that making the by-pass cap discharge across the cat resistor....from ground to the cathode of the tube.?
Thank You

[plexitone]

Not exactly "rudimentary" but this explains it very well:
http://www.freewebs.com/valvewizard1/Co ... _Stage.pdf

Start on page 24.

[C Moore]

Not exactly "rudimentary" but this explains it very well:
http://www.freewebs.com/valvewizard1/Co ... _Stage.pdf

Start on page 24.

Yeah.....OK...I guess that is kind of the way I understand it.
I am embarrassed to say.....I thought the "bypass cap" was somehow directly bypassing the AC guitar signal. And, I could not figure out how the heck that signal was getting across the cap.
Anyway.....seems like maybe I have kind of understood the concept a bit more than I imagined.
Thank You