ORIGINAL MESSAGE:
On Wed, 26 Aug 2009 22:28:40 -0400, jeff millar <jeff@wa1hco.net> wrote:
>>
>I think the statement about grid impedance is true because it refers to
>a principle of _tube_ operation. The grid does indeed have a high
>impedance with _respect_ to the cathode without grid
>current...regardless of amplifier circuit. On the other hand, an
>_amplifier_ may have a grounded grid, but that's a statement about grid
>impedance with respect to amplifier input.
REPLY:
I suppose if you drive ONLY the cathode-grid circuit while the tube is floating
in mid-air and have no other circuit components connected, you will find a high
impedance when there is no grid current.
What that has to do with driving a real grounded grid amp escapes me.
73, Bill W6WRT
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