Hi, I'm learning to use ngspice and gschem via the excellent tutorial [1]http://geda.seul.org/wiki/geda:ngspice_and_gschem I think there are a few small problems which if fixed would make the tutorial even better. I am not sure if this is the relevant mailing list, I thought about geda-bug, but my problems are not software bugs. Anyway, please advise if this is not the right list. Issues: * I'm using gschem 1.4.3.20081231 and ngspice v19 on Ubuntu 9.04. I compiled ngspice from source but the gEDA suite came as a collection of ubuntu packages. * I followed the tutorial all the way through and ran ngspice but got the following message: Supplies reduced to 0.1000% Warning: singular matrix: check nodes 2n3904 and 2n3904 ** Most users will know this output indicates a problem. But, it would be nice to point users to a sample file showing correct output. ** I'd be surprised if this isn't a fairly well known problem. I found a hint via google. My solution was to edit Q1 1 Vbase 2 2N3904 to Q1 1 Vbase 2 0 2N3904 I think the leading 2 in 2N3904 is being interpreted as a node number (for the substrate) by ngspice. The naive user needs to be helped through this, perhaps by modifying 2N3904 to Q2N3904 in the text or just by suggesting the hand edit. * It would be helpful if the reader could download a correct copy of the netlist to compare with theirs. * It would be helpful to "close the loop" and get the user to graphical output, also introducing them to ngspice in interactive mode. I'm suggesting: ngspice [2]spice.net ngspice 1 -> ac dec 20 1 100Meg ngspice 2 -> plot vout vin vbase which produces the attached plot for me. Mike Kordosky References 1. http://geda.seul.org/wiki/geda:ngspice_and_gschem 2. http://spice.net/
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