James -- Thanks so much for providing the info on MacSpice....but I am havin= g=20 a problem getting the application at: http://newton.ex.ac.uk/teaching/CDHW/Electronics2/MacSpice3f5-2.6DR5.gz Get the same "problem" when linking from the web site.....maybe I'm doing=20 something wrong but looks like the file is coming in text form? Dino KL=D8S/4