Among other things, Aaron teaches the late Marshall Leach's analogue analysis courses at the Georgia Institute of Technology. He has just published "On the Application of Thevenin Equivalent Circuits to the Analysis of Vacuum Tube Circuits". It focuses on triodes and the free download is here:
https://www.mdpi.com/2079-9292/12/23/4804
His YouTube page (here:
) is entertaining and informative.
https://www.mdpi.com/2079-9292/12/23/4804
His YouTube page (here: