[Amps] Biasing a Class C modulated final

[Fuqua, Bill L]

  I was thinking about that since there are power1000V 1A or more  MOSFET's .
In fact the ideal thing to do would be to also use a pass transistor that turns off
when clamp is ON to reduce the heat dissipated by a screen dropping resistor. 
  There are many variations. One could be the clamp could function as a shunt 
regulator to maintain a constant screen voltage when signal is applied to the
813s' girds. 
  Perhaps should not make it real complicated. Using a 807 clamp tube would
retain its classic appeal. 

73
Bill wa4lav

________________________________________
From: Amps [amps-bounces at contesting.com] on behalf of Bill Turner [dezrat at outlook.com]
Sent: Wednesday, February 18, 2015 12:46 AM
To: Amps group
Subject: Re: [Amps] Biasing a Class C modulated final

------------ ORIGINAL MESSAGE ------------(may be snipped)

On Tue, 17 Feb 2015 21:13:31 -0500, Paul wrote:

>>   I am guessing common cathode RF amplifier, a more standard way to do
>> it would be an adjustable bias supply and a clamp tube on the screen
>> grid.  (6L6 or similar) look into any pre-1960 ARRL hand book.

REPLY:

A clamp device is a good idea but it doesn't have to be a tube. High
power, high voltage transistors are available dirt cheap anymore. It
will take a little extra circuitry to get the drive right, but that's
dirt cheap too. The hard part is the design.

Bill W6WRT
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