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.
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

On 03/30/2016 09:35 PM, Hank wrote:



And of course superheterodyne and FM...he really knew what he was doing.

Armstrong was a major contributor---but whether he actually "invented"
the superhet seems to be in doubt, as there was considerable French work
in frequency conversion during WWI. No question that Armstrong brought
the superhet to the home entertainment market with the RCA Radiolas of
the early 1920's. These were really strange beasts, as they used a
reflex circuit to reduce tube count. Add to that the "catacombs"
construction---a wax-filled can with V99 tube sockets. I had one of
these (a "portable") from 1924 as a teenager, and really went through
fits to get it to work, after melting all the wax out of the catacomb.
That portable had a "loudspeaker" (a headhone-type driver into a horn)
and an extra v99 to drive it.

Armstrong's FM was really his baby. All the theoreticians said it
wouldn't work, but it did. I once worked with an old-timer who'd been
involved in setting up the original NTSC TV standard in 1941. They
purposely put a hook into RCA's condemnation of FM by specifying FM for
TV audio (said he).




Thanks for the info, I did not know that.

On 03/30/2016 09:46 PM, Hank wrote:

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.

Hank





As I am reading more of de Forest's book I am now at the point where he
finally realized the highest vacuum possible was needed,

On 03/31/2016 07:46 AM, Scott Dorsey wrote:

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.
--scott




I still have one of my textbooks from 1968:


Semiconductor and Tube Electronics by James G. Brazee

In article ,
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

Hank wrote:
Scott Dorsey wrote:
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 was thinking of Seely's _Electron Tube Circuits_ which is the first time
I actually saw the method of load lines. I'd fixed TV sets and done the
military electronics training and thought I had a good idea of how the
thing worked until I read Seely.

Korn and Korn is an interesting book about techniques that basically don't
exist any longer, whereas anything in Seely or in the Radiotron handbook
is probably still in use with jfets.

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.

Don't worry, the same thing is true today. Now they know digital circuits
but not transistors...
--scott
--
"C'est un Nagra. C'est suisse, et tres, tres precis."

In article ,
Scott Dorsey wrote:
Hank wrote:
Scott Dorsey wrote:
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 was thinking of Seely's _Electron Tube Circuits_ which is the first time
I actually saw the method of load lines. I'd fixed TV sets and done the
military electronics training and thought I had a good idea of how the
thing worked until I read Seely.

You're ringing some bells here. The texts I cited are ones that I have
on my shelves, and I see that "Electron Tube Circuits" is a 1950 text
that I do not have.

I, too, was very late to learn about load lines and some other pretty
fundamental stuff. I recall taking a text out of a library that covered
graphical methods for working with tube circuits, one being use of load
lines, and have wondered for years what that text was. Can't remember
the exact year, either, but early fifties is about right.

Korn and Korn is an interesting book about techniques that basically don't
exist any longer, whereas anything in Seely or in the Radiotron handbook
is probably still in use with jfets.

I think Korn and Korn was rather instrumental for us when we designed
the Tek 547 scope. Tek's original sweep circuits (511, etc.) were lifts
from the P4 synchroscope setup (WWII MIT/Harvard radiation labs). Quite
a step up from the relaxation oscillator "sine wave sweep" in the early
RCA and most of the Dumont scopes. However, Tek moved to a "Miller
Integrator" sweep, which was nothing but an op amp circuit. Getting
smart in general about op amps was something I had to develop while I
was teaching for Tek, and Korn & Korn was a bellwether for me.

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.

Don't worry, the same thing is true today. Now they know digital circuits
but not transistors...

Yeah, tell me about it. That design review was a real shock to me, and
fortunately, I was able to segué my way into techniques I'd used in
commercial courses for tube engineers learning semiconductors. Since
then, I've learned in other courses that a good syllabus has to have a
"back to basics" section, often billed as "special considerations when
doing [whatever the course was supposed to really be about]. Bring out
the 19th century stuff, like Kirchoff and Thevenin, then throw in
some impedance stuff---make sure the troops are all up to speed before
trying to move forward.

Nothing like a good Tek 575 as a teaching tool---and pretty handy to
have (I have one) when trying to replace germaniums with silicons in an
audio totem pole circuit.

Hank