> Do you mension about green and orange lines?
> These lines are drawn by lines below.
> segments(Ebb, 0, 0, Ebb/(Rp+Rk), col="blue") # normal common cathode load line
> segments(Ebb, 0, Ebb/2, Ebb/(Rp+Rk), col="orange")
> segments(0, 0, Ebb/2, Ebb/(Rp+Rk), col="darkgreen")
While going over pctubes again, I found a few plots without R commands or does not correspond to the intruction provided in the text, for example. for the dynamic grid characteristic of the 12AU7, the output from plot is quite different from the one shown on the page.
> The other reason is that 300B's characteristic curves are not so correct.
> In your plot, the curve for Eb=350 is more straight than that for Eb=300 and
> the curve for Eb=450 is more straight than that for Eb=400.
> Don't you think that this is strange?
There was only one curve Eb=300V (the red line) in the attached file, I will try at lower voltage and see how they look. Thanks again for your kind advise.
With real tubes, there are some leakage current around cutoff.
One reason for this is that some electron from a filament don't go through the control grid but go directly to the plate.
The other reason is that 300B's characteristic curves are not so correct.
In your plot, the curve for Eb=350 is more straight than that for Eb=300 and
the curve for Eb=450 is more straight than that for Eb=400.
Don't you think that this is strange?
My tube model is good at low Eb region but not so good at high Eb region or cutoff region.
I just tried to plot the gm curve for the 300B, but as you can see from the attached file, it has a concave shape instead of the slight "S" shape shown in the datasheet. I also tried other tubes, and their gm curves had a similar concave shape. What might be the reason for such behavior?
The English to Japanese translation is definitely a concern for full understanding on my part but I believe your detailed modelling of Pentode vacuum tubes is vital to some research I am conducting on the 5879 sharp cutoff Pentode and the 6BJ6 variable mu Pentode. Are you still active in this activity?
KF characteristic is not suitable for examining the operating condition of the tube.
The reason that I show KF characteristic is to compare KF with ultralinear and triode connection.
From KF characteristic we see internal resistance of power stage graphically.
However, we can't determin full swing condition (grid voltage gets 0 V) from it.
So KF characteristc is for demonstration purpose only and I use pentode characteristic diagram for designing power stage.