One of the greater frustrations I've found in teaching has been a long and deep-rooted irritation with the "modern" way of doing things.  This idea that the world must be run through GUI instead of through the command-line is just obscene.  The PSPICE program that most of my students have been forced to endure is just horrible, and now that OrCAD has decided to withdraw most of it's support for the student edition of PSPICE, I have to believe that they will eventually drop that package, altogether. Whatever shall we do?

Enter GNUcap, a simple to use (although you have to use the command line) SPICE program that has most of the capabilities of other SPICE programs, but without the bulk of a price tag.  Yes, it is also without the burdon of a nice simple GUI, but when I consider the incredible nuber of hours I've watched students struggle with a wire that "looks like it's connected, but isn't," I can't help but wonder how "simple" and "convenient" that GUI really is.  LT-Spice has not been as frustrating, and many students have chosen to use Simulink and/or MultiSim, but again, these just carry such heafty price tags for non-students, they are not viable options for the small business or hobbiest.  Again, welcome GNUcap!

As on many other pages of mine, I am going to advocate Eagle software from CADsoft.  It is much (MUCH) easier to work with than OrCAD for schematic capture.  But for the purposes of SPICE, Eagle is not designed for SPICE, and that is where it's usefulness ends.  (Eagle is designed for circuit board layout, with which I have produced several boards with great results.)  I have plans to adapt the netlist that is exported from Eagle into a SPICE-formatted file.  Saying I have "plans" to do this is NOT the same as saying I have time for this, but if you come back to this page every three or four years, maybe someday it'll be here waiting!

OK, so now for what you're looking for - how to use SPICE without the oh-so-useful GUI.  SPICE is a text-based file, somewhat similar to a programmed language source file.  It is (generally) a human-readable file that can be viewed and editted in any text editor.  A common practice is to keep everything in upper-case, although I have not yet found any good reason for this other than the nostalgic practice of those old guys, fat and bald (crap, I just described myself!), sitting hunched over a keyboard and monitor, who seemed to not have a "Shift" key, or at least too lazy to bother using it.  This is only a practice, and not required (not that I am aware of, any way).

GNUcap's source code.... Oops, I just heard someone panic.  Yes, GNUcap comes as source code and you must compile it yourself.  In linux, this is no problem, as root:

> ./configure
> make
> make install
and you're done.  In Micro$oft, if you have the gcc copilers installed, it's the same as linux.  (I think.)  If you are using the Borland Compilers, you may have some minor tweaking, but I don't think it'll be too terrible.  If you are using Visual Studio.... Let's face it, you spent enough on Studio, that you don't care about paying for other SPICE programs anyway.  Still, if anyone is able to build the GNUcap suite under Micro$oft, and if you're willing to share, I will post it here and I have no problem sharing credit for the hard work you just put in!

Oh, OK. I found the Windows binaries online, somewhere.  I don't remember where.  Here they are.

OK, so you have it compiled and installed! Moving on... here is a page that gives a very high-level overview of how to use GNUcap.

Things I'm working on...

Using GNUcap and GNUplot
Using Eagle and GNUcap
Not sleeping for 3 straight days

Wenton's email (wenton@ieee.org)