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Scott Dorsey wrote: Hank wrote: DeForest's misunderstanding of the principles of the Edison effect and the Fleming valve seems to have been pretty basic. His first attempts to control current flow were "grids" mounted on the outside of the glass envelope. And he always seemed to think that what he was controlling was ionized gas conduction, not electrons emitted from a cathode element. Likely some of what he was controlling _was_ ionized gas conduction. This isn't a good thing from the standpoint of getting low distortion but if you want a high mu and don't care about reliability or repeatability I can see it. There were tons of texts written around 1920 that had some pretty strange theories about what tubes did inside. As I recall, the first really good text on radio circuits I encountered was Mary Texanna Loomis's text from the late 20's. I learned EE basics from her text, Ghirardi's "Radio Physics Course" from 1932, and Terman's 1937 "Radio Engineering." One text that baffled me was Zworykin/Morton "Television," which I got as a present at the end of WWII. No wonder--the physics were much too advanced for me to understand. Looking back some years later, I think the best text on vacuum tube physics was Spangenberg's "Vacuum Tubes." It wasn't published until the dawn of the transistor era, so never got the play that Terman and some of the others did. What about Seely? That's what we used in my freshman EE class and it seemed pretty good. If the Seely text you are talking about is "Electronic Engineering" (McGraw-Hill, 1956), yes, that is a good text, and much better than Terman's 4th edition (also 1956). Millman-Seely "Electronics" (1941) is also reasonably good. Seely 1956, along with Millman & Taub "Pulse and Digital Circuits" 1956---these are after my "initial training" time. Also Korn&Korn (1952) on analog computers and op amps. I acquired these texts back in the mid-late 1950's, but in 1956, I was already working for James Millen. A lot of my thinking about EE training in that era came from teaching in Tektronix 1962-64, and what we had to focus on to bring a new-hire experienced engineer up to speed on the "Tekronix Way." I still call that "All the stuff that's not in Terman and Radar Electronic Fundamentals." I mention Spangenberg "Vacuum Tubes" (McGraw-Hill 1948) because it's a fat book devoted completely to tube physics. That book would be a good text for a 2-semester upper division/graduate course, much more comprehensive on that particular topic than was in a general EE circuits course, where Seely 1956 would be much more appropriate. But by 1956, tubes were passé, and we who were teaching had to put a lot of time in recalibrating engineers on transistor design techniques. I did use material out of Spangenberg 1948 at Tek, both in teaching and in design, but I think that given how rapidly things were moving toward sand-state, any serious course treatment would have been déja vu all over again. I still remember having a design review of something that included a built-up 2N222 type "or" circuit that was bogging down until I realized that none of my reviewers understood basic transistors. That was ca. 1970. It was "back to basics" time to deal with that. Hank |
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