>
> I like the idea of modeling the circuit. However,
>much of the circuit is not considered. People often don't realize that
>that there are additional inductances due to the current paths thru the
>chassis and often these impedances are in both the input and
>output circuits. I have seen many amplifiers that have very long paths
>from the anode (PLATE) thru the coupling capacitor, PI input capacitor, to
chassis and
>back to the grid and cathode circuit. Sometimes this path is a foot in
>length or more
>. This single loop amounts to nearly a uH of inductance with
>who knows what other impedances tied to it and signals sharing the path.
> My electronics instructor used to say often the problems with a circuit
>is the component you can't see. Especially with RF circuits.
>
Amen to that, Bill. Who would ever have guessed that there is a
Z-step-up L-network hidden inside the Tune-C in a 922?
cheers
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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