[Boatanchors] Theory Question

[Michael Bittner]

Keith,

You will often see two parallel bypass caps for the screen grid of 
regenerative receivers that control regeneration by varying the screen grid 
voltage with a potentiometer.  The purpose of the smaller of the two caps 
(anything from 100 pF to 500 pF) is to bypass the screen grid for RF since 
the larger one may become inductive at RF.  The larger of the two (typically 
0.1 uF to 0.5 uF) is for bypassing the screen grid for audio and especially 
for the scratchy noises that may be produced by the pot.

Mike, W6MAB
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----- Original Message ----- 
From: "Keith Densmore" <ve3gem at gmail.com>
To: <boatanchors at mailman.qth.net>
Sent: Wednesday, July 29, 2015 7:55 AM
Subject: [Boatanchors] Theory Question


> Have a question I know someone will know the answer to.
> Very often in tube bypass capacitors, both b+ and cathode, two caps are 
> used, a
> lower value and a higher value, ie .01 and a .001.
> What is the purpose of this, would not the .01 do the job alone? Never 
> seen
> this addressed.
>
> ---
> New Outlook Express and Windows Live Mail replacement - get it here:
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>
> Thanks,
> Keith ve3ts


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