Re: gEDA-user: simulation advice

[al davis <ad136@xxxxxxxxxxxxxxxx>]

On Tuesday 03 April 2007 09:51, Patrick Doyle wrote:
> > With gnucap you can use "fault", "modify", "param" to
> 1) How would I model a switch?

The switch device?  Type "S".  (Same as Spice)

> 2) Did I forget a switch when I built Gnucap that would
> enable an X windows plot, or does Gnucap only support ASCII
> plots? 

Gnucap only directly supports ASCII plots.  If you want a nice 
plot, use "gwave".  I plan to make it hook up automatically, 
but for now you need to do:

print ac .......
ac 20 20k oct 10 >some_file
!gwave some_file

(notice ... the "print" command, not "plot")


You should be able to do:

ac 20 20k oct 10 | gwave

but gwave doesn't work in a pipe.

> 3) I fetched the spice model for an MMBT3640 from 
> Fairchild, and saw that my simple circuit loaded up in
> ngspice, but when I attempt to load it in Gnucap, I get:
>
> * gnetlist -g spice-sdb -s -o mictest.ckt mictest.sch
> .MODEL  MMBT3640  PNP   LEVEL = 1   IS    = 1.41E-15   ISE
>                   ^ ? no match
>
> (Note that the "^ ? no match" points to the word PNP in the
> line above.

That's wierd.  It should work.  PNP should find the native BJT 
model.

> Does this mean I need to "attach" to an ngspice model
> somehow?  If so, how?

That kind of message could mean you need to "attach" a model, 
but it doesn't here.  It should work.  Send it to me and I will 
look at it.

How to attach a model is with the attach command. 

"attach my_model.so"

This is in the manual.  There is a tutorial supplied in the 
tarball, but it needs updating.


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