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Re: gEDA-user: simulation advice
The reason it works with ng-spice and not gnucap is that it was
written for ng-spice not gnucap.
Gnucap doesn't have levels for the BJT unless you use plugins.
You uncovered a bug that came about with the plugins -- in how
it handles that. The old version would just ignore the level
keyword. The current one got an error because it only found
a "PNP" with no level, as opposed to a PNP level 1. The bug is
that the arrow points to the wrong place. Spice 3f5 would not
accept the level either. It still gets a warning on the "NK"
parameter, and ignores it. That is the same in gnucap or
ngspice, or in gnucap with spice3f5 of ngspice models.
Since you mentioned it, and I didn't think of it before, it is
easy to change it, so I did ..
Thanks... I'll go apply the patch, thus answering my question whether
I should be running a development snapshot or a release snapshot -- 2
answers for the price of one question, very economical :-)
Then you have the ".include Simulation.cmd" in the middle of the
circuit description.
That's an artifact of "gnetlist spice-sdb" -- I'm not sure how it
decides where to put the .INCLUDE directives, but in the limited (3 or
so) examples at which I've looked, they seem to show up somewhere in
the middle.
Inside it, you have the print after the
tran command.
That's an artifact of me trying to figure out how to use ngspice in
batch mode. When I first started playing with my circuit, I loaded it
into ngspice, executed the "OP" command, printed voltages out at
various nodes, typed "quit", typed "yes" when I was asked if I really
wanted to quit, and got tired of all of that typing. So I tried
putting the OP command into the script, but when I read the
documentation for the .PRINT command, it didn't seem like it supported
a PRTYPE of OP (I guess I could have just tried it -- maybe I did).
So I changed to a transient analysis with the thinking that I just
wanted to print out the steady state value at the end.
Putting the simulation commands in the middle of the circuit
description gives you a simulation of the part of the circuit
you have up to that point. It works, but gives a different
result than the whole circuit would. This is another
difference between gnucap and spice. The gnucap way allows you
to build a circuit in steps and test after each step. Build
part, test it, build another stage, test it. Or .. build it,
test it, change it, test again, ... You can't do this in
spice.
That's cool.
Thanks once again...
--wpd
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