[Amps] RF parts and parasitics!!

[Bill, W6WRT]

ORIGINAL MESSAGE:

On Wed, 26 Aug 2009 22:28:40 -0400, jeff millar <jeff at 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