Thanks to Gizmodo, I found this fun old (1942) video on YouTube. It’s an RCA documentary explaining how vacuum tubes are made and used, split into two parts.
Part 1 (9m 31s):
Part 2 (9m 16s):
And yes, I’m aware I missed getting out a “Carnivalia” post this week — it got lost under the load of a bunch of offline life commitments. I’ll get it online somewhere over the course of this weekend. In the meantime, enjoy this neat old video!