In a message dated 4/10/06 6:29:04 PM Central Daylight Time,
amps-request@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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