[Amps] RCA load impedance calculation

[TexasRF at aol.com]

Jeff, I misread your example and took your peak current of 1 A as the  
average current. Your 5400 ohm plate load is exactly correct for the example and  I 
must sincerely apologize for my confusion. I have been working with an 8877  
amplifier recently and must be trying to make your example fit that.
 
Thanks/73,
Gerald K5GW
 
 
In a message dated 4/10/2006 8:48:48 P.M. Central Standard Time,  
Xmitters at aol.com writes:

In a  message dated 4/10/06 6:29:04 PM Central Daylight Time,  
amps-request at contesting.com writes:

<< Gerald,

I went  ahead and brought the RCA transmitting tube manual TT-5 here to quote 
what  it says.

Effective RF load resistance;

2 x (Eb - Ebmin) /  Ibo

Ibo = Zero signal plate current

"Ibo should be between 1/6  and 1/10 of Ibmax found on the typical plate 
characteristics  graph".

"Determine peak plate current (Ibmax) for zero bias (Ec1 = 0)  at or slightly 
below the knee of the zero-bias curve for the value of  Ec2". 

>>

Hello:

I'm looking at my copy of  the RCA Transmitting Tubes book, TT-5 page 53 
equation 15.

RF Load  impedance is = 2 * ( Eb- ebmin)/ Ibmax   (Ibmax not Ibo  )

Maybe there is a mis-print in your book. It is also hard to read. So  using 
my 
example numbers in my original post for a class B:

Rload =  2 * (3000-300)/1 = 5400 Ohms

Ibo is the idling plate current with no  signal, and I don't see how that 
would be an appropriate parameter for  calculating the required load 
resistance the 
tube wants to  see.

Jeff  Glass
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