Re: [Help-gnucap] getting started with gnucap

[Felix Salfelder]

On Sun, Feb 04, 2018 at 11:46:55AM +0100, Patrick Mulder wrote:
> http://gnucap.org/dokuwiki/doku.php?id=gnucap:manual:examples:hello_world
> [..]
> gnucap> list
> Vd ( 1 0 )  DC  10.
> D1 ( 0 1 )  diode_dut NA( 1.)
> gnucap> probe op v(nodes)
> D1: can't find: diode_dut
> 
> I get the error above.

Hi Patrick

welcome to gnucap.

when you attach probes, the circuit is expanded with all models. and
there is no "diode_dut" defined anywhere, hence the error.

have a look at tests/d_diode.1.ckt. theres a .model statement in line 6.
a line such as

gnucap-spice> .model diode_dut d

will define a diode (aka "d") parameterset diode_dut with default parameters.

(note that "d1 0 1 d" should just work, but doesn't. thats due to spice
model semantics legacy.)

> 2) How can I plot the the DC curves of the transistor ?

instanciating a bjt works in a way similar to the diode. look at the
tests/*.{ckt,gc}.

generally, you can send the output of a simulation command to a file, or
to another process.

gnucap-spice>.dc vsrc 0 1 .1 > file.out
gnucap-spice>.dc vsrc 0 1 .1 | ./postprocess.sh

the file.out format is really simple, gnuplot reads it without
modification. also gaw, some kind of graphical plotting tool, reads it.
parsing into python is trivial etc.

> 3) I think the Python based plot syntax of gnucap-python
> https://github.com/henjo/gnucap-python looks interesting, or combined with
> https://matplotlib.org/ maybe - but the Python plugin does not seem to work
> with my current build.

i use python/matplotlib myself, rather excessively. interfacing to
python would be really nice. no time to do it. if henjos stuff seems
fixable, or you need help with doing anything else, please ask.

cheers
felix