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Old 12-29-2023, 05:22 PM
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Penthode Penthode is offline
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Join Date: Jun 2009
Location: Kitchener/Waterloo Ontario Canada
Posts: 1,073
Quote:
Originally Posted by Doug View Post
one guy that was a member on arf has
My friend John Folsom says, 'It's all about the spares.'"
-Bob the Antique TV Guy in 2021

so
good luck
Yes, it is all about spares. But as time marches, it it all about creativity and much of the time making spares!

I was looking at the high voltage MOSFET option to replace the transformer. It is a way lot cheaper (parts under $10) and maybe more efficient and less prone to breakdown.

Looking at the FETs these days, they have a very large transconductance so with such a light load, the gain should be achieveable with a single moderate power MOSFET.

I have thrown in some values for a generic MOSFET to achieve the bias voltages and quieesent point of around 225 vdc to allow for a wide swing. I anticipate average vertical convergence level will only be in the region of 50 to 100 volts p-p to the convergence plate. But that is just a guess.

Find updated my circuit with some component values. In the drawing where my circuit is inserted into the CT-100 circuit, I left a gate resistor with no value to provide the option to reduce gain.
Attached Images
File Type: jpg CT100_Convergence_Concept.jpg (76.6 KB, 21 views)
File Type: jpg FocusCCT-CT100e.jpg (101.2 KB, 24 views)

Last edited by Penthode; 12-29-2023 at 05:56 PM.
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