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[Help-gnucap] newbie: edit and BJT's

From: Hugo van der Merwe
Subject: [Help-gnucap] newbie: edit and BJT's
Date: Wed, 2 Oct 2002 15:21:19 +0200
User-agent: Mutt/1.4i

I've recently started playing with gnucap (in the past I used ng-spice
a little). Something I noticed as odd was this:

Starting with a clean gnucap session, I type edit, and add e.g.:

 Q1  1  2  3  4  tr2n2222

Save, quit. Run edit again, it presents:

 Q1  1  2  3  4  tr2n2222  area= 1.  icvbe= NA  icvce= NA  temp= NA

Seeing this doesn't surprise me, but exit the editor again:

 ... 2  3  4  tr2n2222  area= 1.  icvbe= NA  icvce= NA  temp=
                                         ^ ? what's this?

Running edit again presents:

Q1  1  2  3  4  tr2n2222  area= 1.  icvbe= 0.  icvce= NA  temp= NA

Quitting results in complaint about the next NA, and so it continues
until all turn to "0". Curious.

The other thing, is there something clearly wrong and/or unimplemented
in this model:

*  Fairchild Semiconductor 2N3904
.MODEL tr2N3904 NPN (Is=6.734f Xti=3 Eg=1.11 Vaf=74.03 Bf=416.4 Ne=1.259 
+ Ise=6.734 Ikf=66.78m Xtb=1.5 Br=.7371 Nc=2 Isc=0 Ikr=0 Rc=1 Cjc=3.638p 
+ Vjc=.75 Fc=.5 Cje=4.493p Mje=.2593 Vje=.75 Tr=239.5n Tf=301.2p Itf=.4 Vtf=4 
Xtf=2 Rb=10)

Both ng-spice and gnucap present very strange results when I use this in
a cascode amplifier circuit instead of a 2N2222. (I can send this
netlist if needed.)

That brings me to my last two question at this moment:

Is there some place to find a nice summary of what has been implemented
and what has not in terms of spice2/spice3 compatibility?

How far down the line might monte-carlo analysis be, years, or months?

Hugo van der Merwe

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