>
>Rich says;
>
>>Also, at say 14MHz, the grid is changing considerably faster than every
>5uS.
>
>I don't follow what that has to do with it. The screen volts follow the
>envelope of the signal, not the individual RF cycles.
With screen potential wandering about, some input cycles produce little
anode current and some input cycles produce much anode current.
>
>Same way as the Collins high efficiency solid state PA in the late 60's or
>early 70's, that modulated a switching supply to vary the Vcc in sympathy
>with the modulation envelope.
>
>The original G2DAF used 7000pF total screen capacity; the diodes had a
>resistance of between 5 and 12 ohms, depending on the current, and the
>source impedance was lower than 300 ohms. So the tc would be around 2.5
>microsecs. This suggest very little phase delay between the screen volts and
>the RF envelope.
>
In 2.5uS, a 14MHz sinewave goes through how many polarity reversals?
>
later, Peter
- Rich..., 805.386.3734, www.vcnet.com/measures.
end
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