Jim, please bring me up to speed on why the switcher will not work with a
directly heated tube. I am not challenging the information; just asking for
enlightenment!
73,
Gerald K5GW
In a message dated 10/7/2010 5:00:11 A.M. Central Daylight Time,
jim.thom@telus.net writes:
--------------------------------------------------
From: "W2XJ" <W2XJ@W2XJ.NET>
Sent: Wednesday, October 06, 2010 9:05 PM
To: <TexasRF@aol.com>; <jim.thom@telus.net>; <amps@contesting.com>
Subject: Re: [Amps] Switching Supplies for High Current Filaments
> This is easy with a switcher. Switching designs include PWM controller
> chips
> designed for that purpose. They have various external inputs for voltage
> control, current limit, etc. It takes a few small resistors and one cap
to
> implement a soft start to ramp up the voltage. Current limiting can also
> be
> easily implemented on these chips with the correct sensing.
>
> Advantage is a smaller, lighter, cheaper and easier to wind transformer
>
## The caveat is you can't use any version of a switcher... when used
with
a
directly heated [thoriated tungsten] GG triode. However, ur scheme
would
work
with directly heated tetrodes.... like a 4CX-5000.
Jim VE7RF
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