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Voltage regulator tubes vs zeners (tubes has BETTER stability)
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001:
marvelous  :-+
is it way to use current sink to avoid direct current?
chris_leyson:
Mr Carlson's Zener Diode vs Tube Regulation video was interesting because I had never considered the tempco of gas regulator tubes. Temperature coefficient depends on the gas mixture. Neon with Helium can have positive or negative temperature coefficient. Reference "British Special Quality Valves and Electron Tube Devices Data Annual 1964–65" page 810 onwards, Google Books link below.
LM723 used as a shunt regulator with an external transistor might be an option to replace high voltage zeners. LM723 has a buried zener reference so it's nice and quiet.

https://books.google.co.uk/books?id=8K83BQAAQBAJ&printsec=frontcover&dq=%22British+Special+Quality+Valves+and+Electron+Tube+Devices+Data+Annual+1964%E2%80%9365%22&hl=en&sa=X&ved=0ahUKEwiPwovMlZrlAhVYUxUIHb5-BaUQ6AEIKDAA#v=onepage&q=%22British%20Special%20Quality%20Valves%20and%20Electron%20Tube%20Devices%20Data%20Annual%201964%E2%80%9365%22&f=truehttps://books.google.co.uk/books?id=8K83BQAAQBAJ&printsec=frontcover&dq=%22British+Special+Quality+Valves+and+Electron+Tube+Devices+Data+Annual+1964%E2%80%9365%22&hl=en&sa=X&ved=0ahUKEwiPwovMlZrlAhVYUxUIHb5-BaUQ6AEIKDAA#v=onepage&q=%22British%20Special%20Quality%20Valves%20and%20Electron%20Tube%20Devices%20Data%20Annual%201964%E2%80%9365%22&f=true

Zero999:

--- Quote from: 001 on October 14, 2019, 01:35:49 pm ---marvelous  :-+
is it way to use current sink to avoid direct current?

--- End quote ---
What do you mean? Are you talking about using the TL431 at higher currents than 100mA? It's possible to add a PNP pass transistor to divert current around the TL431, once it exceeds a certain threshold. Refer to page 27, figure 31, on the TL431 data sheet. When the current through the TL431 exceeds R3*VBE the BJT starts to conduct, diverting current, around the TL431. It can be combined with the cascode circuit I showed you above.

http://www.ti.com/lit/ds/symlink/tl431.pdf
001:

--- Quote from: Zero999 on October 14, 2019, 06:22:44 pm ---
--- Quote from: 001 on October 14, 2019, 01:35:49 pm ---marvelous  :-+
is it way to use current sink to avoid direct current?

--- End quote ---
What do you mean? Are you talking about using the TL431 at higher currents than 100mA? It's possible to add a PNP pass transistor to divert current around the TL431, once it exceeds a certain threshold. Refer to page 27, figure 31, on the TL431 data sheet. When the current through the TL431 exceeds R3*VBE the BJT starts to conduct, diverting current, around the TL431. It can be combined with the cascode circuit I showed you above.
(Attachment Link)
http://www.ti.com/lit/ds/symlink/tl431.pdf

--- End quote ---

No. Not for current reason but High quiet and stable voltage to use it as reference in serial regulator
001:
In fakt TL431 is not good choise for HV circuit
it oscillate  :horse:
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