Pspice used to be very good. They'd have free evaluation copies for you to try out small circuits (up to one page, about 50 elements). Search the web and you may find it as "evaluation" version for either "pspice" or "the design center".
Microcap is another commercial product by Spectrum-soft that has a free eval version. This works for approx. 50 elements, and allows you to save files (very handy), which a number of eval versions do not allow. I have used it for filter design and simple active circuit models. A fair number of features are active in the eval version. I have a low SW pain threshold, and this application was not too bad to learn the basics and be useful.
I searched a few years ago and bought a package (Tina) from Designsoft. It was true spice based and works well. I just checked and they have a new V7 product that includes VHDL (I had to buy that extra)
Another interesting piece of software is "Sapwin" (cirlab.det.unifi.it/sapwin/). It takes a schematic and creates a symbolic expression for a transfer function which can then be manipulated in mathcad. See attached article.
On 8/24/2006 4:04:07 PM, johnfin wrote: >Is there a good >graphical/numeric electrical >circuit design program similar >to the mathcad layout? I have >tried Circuit Shop and it's >junk.
Have you looked at VisSim. A limited version was packaged with Mathcad 11 (I believe) It allowed you to create discrete and analog circuits using both passive and active elements. You could then select your input wave forms and run simulations. And you could link it to Mathcad for analysis.