Looking for pointers on Deflection Amplifier Output Stage Design

[LukeSimon]

I have updated the CRT Deflection Calculator to also calculate the specs for the impedance matching output transformer, as well as the flyback capacitor, peak primary, and peak secondary side voltages, using the derivations from Gulati's textbook.

[AlanInSitges]

That's really great work you're doing!

[LukeSimon]

Originally Posted by AlanInSitges

That's really great work you're doing!

Thanks for the encouragement. I finished the reading list I posted earlier, and found the the two papers from RCA's engineer Otto Schade to ultimately be exactly what I was looking for. His papers are in RCA's Journal of Television Volume V and RCA's Journal of Television Volume VI. It turns out that Schade's two papers were quite famous for their time, as they were the first publication that fully explained what became the standard circuit design for the horizontal output stage.

Schade has horizontal deflection formulas that are equivalent to those from Zworykin, which makes sense. Zworykin was Schade's colleague at RCA. Anyway, their formulas for the required deflection current have a parameter for the outer to inner deflection ratio. Read the papers for the detailed definition. The value that they use in their examples for this parameter is 1.66, but based off of my real world measurements for color CRTs, the parameter value is 6.82. This makes sense, as the published formula and examples they used were for black and white CRTs.

Another great paper is "Deflection and Convergence of the 21-inch Color Kinescope". Again, an RCA research publication, but about 6 years after Schade and Zworykin's publications, and this time describes the horizontal output stage for an early color TV. When I apply Schade/Zworykin's formula for the current required for horizontal deflection for an X-degree CRT, a Y-inductance yoke, and Z-volts ultor... as long as I use 6.82 for the parameter mentioned above, the required current is exactly what "Deflection and Convergence of the 21-inch Color Kinescope" specifies. So the Schade/Zworykin formula tests out for both early color CRTs and late color CRTs (by my personal measurements of my late 1990s CRTs).

One last recommended reading, is just 8 pages. There is one of the most amazing vintage TV restoration enthusiasts that I just learned about, Dr Hugo Holden. Looking at some old forum threads on another site, it looks like he realized, like me, only decades earlier than me, that television textbooks do not provide enough detail about the design of the horizontal output stage. Dr Holden wrote this 8 page article to give an overview of the theory and design of the horizontal output stage, and Dr Holden has clearly read Schade's work and more. It is a terrific read. Any chance Dr Holden lurks on these forums?