Werner Simbuerger

In my case, it turned out that ILIMIT (Current Limiter) can be quite tricky when it comes to SPICE simulation convergence. The parameters are not easy to set correctly. See Section 8.2.14, page 202, of the Ngspice manual: https://ngspice.sourceforge.io/docs/ngspice-47-manual.pdf An easier approach is to use a B source connected in series with the main voltage source. The B source acts as a current-controlled voltage source that adjusts the voltage of the main source: Qucs 26.1.1 /home/werner/Documents/HPPI/QUCS-S/HPPI_HV10_5_prj/test.sch...

I agree with 1), because set format x '10^{%T}' is the preferred and elegant solution to solve the original problem.

I was able to verify the same behavior in <<plot3.plt>> and <<plot3.pdf>></plot3.pdf></plot3.plt> At least in earlier Gnuplot release there were probably no objects created outside plotting area without any plot area margin extension. If it is intended to keep the "feature" of grid line extensions outside plotting area without any label, it is probably enough to extend the user manual, e.g.: http://www.gnuplot.info/docs_5.4/Gnuplot_5_4.pdf Page 149, paragraph "Format": include example set format...

This is indeed a very elegant solution. Using: set format x '10^{%T}' the unwanted "artefact dashed vertical line" near the y-label does not show up anymore. Demo: plot1a.plt and plot1a.pdf This is of course the better way to define the exponential x-format. But, maybe the origin of the "dashed line artefact" due to "set xtics add ("10^{-12}" 1e-12, ... )" can be corrected in the source code in order just to be backward compatible with old plot files which use "set xtics add (...)".

"set xtics add ()" creates unwanted artefact dashed vertical line

Thank you Ethan for pointing me to the sample issue. set sample 2000 or set samples 2000 have same effect, and solve the issue. In my case f(x) exists only inside the region [0:60]. Therefore, I could restrict the samples command to f(x): [0:60] f(x) title "" lw 3 lc rgbcolor "0xED1847" axis x1y1,\ which also works. Probably a gnuplot warning could help, in order to identify potential plot artifacts, if the sampling interval exceeds maybe 1% of the full plot range.

Update: I found the error, unfortunately it was my fault - sorry - I forgot to set...

"top_1.sch" is the better combined schematic to simulate both S-parameter and transient...