Electronics Computer-Aided Design Using gschem to simulate active circuits with ngspice

Bookmark this page:  YahooMyWeb Yahoo!  Google Google  Windows Live Favorites Windows Live  del.icio.us del.icio.us  digg digg  Add to Netscape Netscape
Subject Author Date
Using gschem to simulate active circuits with ngspice sw 08-30-08
Posted by sw on August 30, 2008, 4:44 pm
Please log in for more thread options


I have gschem and ngspice running under Ubuntu Hardy and have
successfully simulated passive (RLC) and a few with NPN and/or PNP
transistors.

I am having difficulty properly setting up simulations using
operational amplifiers (i.e. TL071) or MOSFETS (i.e. 2N7000). I have
been able to successfully download the Spice 3 models (as
'subcircuits') from manufacturer's sites and associate them with the
schematic symbols in gschem (by setting the 'file' attribute).

Possibly my problem is a misunderstanding of pin numbering and how to
line up pin numbers on a schematic symbol with those in a subcircuit.
I seem to have this problem with operational amplifiers especially.

There are also other strange things I am stuck on, for example, why
the gschem MOSFET parts have varying numbers of pins:

nmos-1.sym: 4 pins
nmos-2.sym: 4 pins
nmos-3.sym: 3 pins

Which should be used for simulation with, for example, the 2N7000
model? I imagine it ia nmos-3.sym but what are the other symbols used
for, in that case?

Can anyone recommend good books or other sources of information for
guiding someone like me through the fundamentals of using Spice and
gschem for active circuit simulation? I've seen many of the gEDA/
gschem tutorials and they all seem to skip this aspect to some extent.
I could really get a lot from a single, clear article that explains
how to set up a simple operational amplifier circuit simulation, step-
by-step, in gEDA/gschem/ngspice!

Thanks.

Similar ThreadsPosted
Using gschem to simulate active circuits with ngspice August 30, 2008, 4:44 pm
Modeling Series R in an MOS (Active Device) Capacitor ?? February 4, 2005, 2:41 pm
Active Filter Design Software Recommendation ? February 28, 2005, 3:04 pm
ERROR_INVALID_PIN in gschem June 27, 2005, 4:36 am
gschem -- List of footprints May 4, 2005, 5:10 pm
geda/gschem setup problems April 18, 2005, 8:53 pm
gschem libgeda.so.22 problems with v2005! May 2, 2005, 1:45 am
gschem/pcb (geda) simm72 correct? May 25, 2006, 11:48 am
gEDA gschem: "Write image" resolution October 7, 2008, 9:13 pm
Intersting Circuits March 31, 2006, 11:48 am
How to Put Different Circuits - with Different Profiles in One Project? September 29, 2006, 7:36 am
large spice circuits June 27, 2008, 10:19 am
SImulate a *.spi file July 23, 2004, 1:32 pm
EXCELLENT Quality Circuits book August 6, 2007, 2:43 pm
Component librarys for mini-circuits December 3, 2007, 10:44 pm