Hi r , Thanks, that works perfect :-)
Cédric r wrote : > Hi, > > There is no DC path from node '1' to the ground (node '0'). Add a > large resistor between them and the simulation will work: > > Tranfer function > ISRC 1 0 AC 1 > R1 1 2 1k > C1 2 3 1u > R2 3 0 1k > C2 3 0 1u > R10 1 0 1e+12 > .AC DEC 10 1 10K > .END > > Actually, Ngspice tried to fix it by inserting GMIN to the circuit (a > small conductance between each node and the ground) but for some > reason it didn't work. Does anyone knows why? > > Cheers, > -r > > On Sun, Aug 23, 2009 at 10:23 PM, cedric<cedric_li...@bbox.fr> wrote: > > Hi, > > I am a ngspice newbie and I'd like to get a frequential transfer > > function of a Wien filter > > as an exercise . > > I'd like to plot V(3)/ISRC versus frequency . > > > > Here is the .sch file I simulate : > > > > Tranfer function > > ISRC 1 0 AC 1 > > R1 1 2 1k > > C1 2 3 1u > > R2 3 0 1k > > C2 3 0 1u > > .AC DEC 10 1 10K > > .END > > > > Here is the result I get : > > > > ngspice 1 -> run > > Doing analysis at TEMP = 27.000000 and TNOM = 27.000000 > > > > Warning: Source isrc has no value, DC 0 assumed > > > > Warning: singular matrix: check nodes 1 and 1 > > > > Note: starting dynamic Gmin stepping > > Trying gmin = 1.0000E-03 Note: One successful Gmin step > > Trying gmin = 1.0000E-04 Note: One successful Gmin step > > Trying gmin = 1.0000E-05 Note: One successful Gmin step > > Trying gmin = 1.0000E-06 Note: One successful Gmin step > > Trying gmin = 1.0000E-07 Note: One successful Gmin step > > Trying gmin = 1.0000E-08 Note: One successful Gmin step > > Trying gmin = 1.0000E-09 Note: One successful Gmin step > > Trying gmin = 1.0000E-10 Note: One successful Gmin step > > Trying gmin = 1.0000E-11 Note: One successful Gmin step > > Trying gmin = 1.0000E-12 Note: One successful Gmin step > > Trying gmin = 1.0000E-12 Note: One successful Gmin step > > Warning: singular matrix: check nodes 1 and 1 > > > > Warning: Dynamic Gmin stepping failed > > Note: starting source stepping > > Supplies reduced to 0.0000% Warning: singular matrix: check nodes 1 and > > 1 > > > > > > Trying gmin = 1.0000E-02 Note: One successful Gmin step > > Trying gmin = 1.0000E-03 Note: One successful Gmin step > > Trying gmin = 1.0000E-04 Note: One successful Gmin step > > Trying gmin = 1.0000E-05 Note: One successful Gmin step > > Trying gmin = 1.0000E-06 Note: One successful Gmin step > > Trying gmin = 1.0000E-07 Note: One successful Gmin step > > Trying gmin = 1.0000E-08 Note: One successful Gmin step > > Trying gmin = 1.0000E-09 Note: One successful Gmin step > > Trying gmin = 1.0000E-10 Note: One successful Gmin step > > Trying gmin = 1.0000E-11 Note: One successful Gmin step > > Trying gmin = 1.0000E-12 Note: One successful Gmin step > > Note: One successful source step > > Supplies reduced to 0.1000% Warning: singular matrix: check nodes 1 and > > 1 > > > > Supplies reduced to 0.0000% Warning: singular matrix: check nodes 1 and > > 1 > > > > Warning: source stepping failed > > > > AC operating point failed - > > > > Last Node Voltages > > ------------------ > > > > Node Last Voltage Previous Iter > > ---- ------------ ------------- > > 1 0 0 > > 2 0 0 > > 3 0 0 > > > > doAnalyses: iteration limit reached > > > > run simulation(s) aborted > > > > Does someone has an idea about what's wrong in the scheme file ? > > Thanks for your help, > > ced > > > > > > > > > > _______________________________________________ > > geda-user mailing list > > geda-user@moria.seul.org > > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user > > > > > _______________________________________________ > geda-user mailing list > geda-user@moria.seul.org > http://www.seul.org/cgi-bin/mailman/listinfo/geda-user > _______________________________________________ geda-user mailing list geda-user@moria.seul.org http://www.seul.org/cgi-bin/mailman/listinfo/geda-user