Hey!
Found this and thought I would share it with you guys. A great watch about tube from AT&T Archives. Love the animations.
https://youtu.be/_-JzxX75oYc Here's another one about tube. "Bottle of Magic"
https://youtu.be/Ul2cKZCz67Y We are now in 2019, and I'm still amazed that it works! From a simple Edison's light bulb that gave birth to all the electronics we have now. Crazy that someone, De Forest in this case, looking at a simple light bulb and came up with a bright idea that it could be use to amplify.
There are other interesting films there in AT&T archives also worth check out. It is interesting how things were back then.
Buddy