On Sunday 18 March 2007 17:42, Wen wrote: > Hi list, > I am going to do Equivalent circuit fitting for a university > project with impedance spectroscopy. > > I am looking for a tool that first allows to define (via a > graphic interface would be best) an electric circuit made of > resistors, conductors, inductors and maybe constant phase and > warburg elements.
I had to look up "warburg elements". Gnucap has constant phase elements. Just specify a complex value for a resistor or dependent source. It looks like it would be easy to make a plugin for the warburg elements. It will be even easier when I get the Verilog-AMS compiler working. For now, you can make a "bm" function plugin, using the ones provided as a basis. Then a resistor or whatever could have a value that follows the warburg function. Or, you could use the model compiler to make a new element, as a plugin. gnucap plugins allow you to add or replace almost anything at run time using the "attach" command. You write in C++, compile to a ".so" and attach it. To get this functionality you need the latest development snapshot. > What i need is a Nyquist-plot of that > circuit-> a plot that shows the imaginary (vert. axis) and > the real (horiz. axis) part of the impedance of the defined > circuit for a wide range of frequencies. Gnucap has impedance probes, so it will give you that directly. You can ask for mag&phase, or real&imaginary. Just ".print ac zreal(outnode) zimag(outnode)" or something like that. You can plot it with octave, gnuplot, R, tcl-tk, or many other tools. gwave doesn't do this kind of plot. _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user