ced Posted August 23, 2009 Report Share Posted August 23, 2009 Hi,I am a ngspice newbie and I'd like to get a frequential transfer function of a Wien filteras an exercise .I'd like to plot V(3)/ISRC versus frequency .Here is the .sch file I simulate :Tranfer functionISRC 1 0 AC 1R1 1 2 1kC1 2 3 1uR2 3 0 1kC2 3 0 1u.AC DEC 10 1 10K.ENDHere is the result I get :ngspice 1 -> runDoing analysis at TEMP = 27.000000 and TNOM = 27.000000Warning: Source isrc has no value, DC 0 assumedWarning: singular matrix: check nodes 1 and 1Note: starting dynamic Gmin steppingTrying gmin = 1.0000E-03 Note: One successful Gmin stepTrying gmin = 1.0000E-04 Note: One successful Gmin stepTrying gmin = 1.0000E-05 Note: One successful Gmin stepTrying gmin = 1.0000E-06 Note: One successful Gmin stepTrying gmin = 1.0000E-07 Note: One successful Gmin stepTrying gmin = 1.0000E-08 Note: One successful Gmin stepTrying gmin = 1.0000E-09 Note: One successful Gmin stepTrying gmin = 1.0000E-10 Note: One successful Gmin stepTrying gmin = 1.0000E-11 Note: One successful Gmin stepTrying gmin = 1.0000E-12 Note: One successful Gmin stepTrying gmin = 1.0000E-12 Note: One successful Gmin stepWarning: singular matrix: check nodes 1 and 1Warning: Dynamic Gmin stepping failedNote: starting source steppingSupplies reduced to 0.0000% Warning: singular matrix: check nodes 1 and 1Trying gmin = 1.0000E-02 Note: One successful Gmin stepTrying gmin = 1.0000E-03 Note: One successful Gmin stepTrying gmin = 1.0000E-04 Note: One successful Gmin stepTrying gmin = 1.0000E-05 Note: One successful Gmin stepTrying gmin = 1.0000E-06 Note: One successful Gmin stepTrying gmin = 1.0000E-07 Note: One successful Gmin stepTrying gmin = 1.0000E-08 Note: One successful Gmin stepTrying gmin = 1.0000E-09 Note: One successful Gmin stepTrying gmin = 1.0000E-10 Note: One successful Gmin stepTrying gmin = 1.0000E-11 Note: One successful Gmin stepTrying gmin = 1.0000E-12 Note: One successful Gmin stepNote: One successful source stepSupplies reduced to 0.1000% Warning: singular matrix: check nodes 1 and 1Supplies reduced to 0.0000% Warning: singular matrix: check nodes 1 and 1Warning: source stepping failedAC operating point failed -Last Node Voltages------------------Node Last Voltage Previous Iter---- ------------ -------------1 0 02 0 03 0 0doAnalyses: iteration limit reachedrun simulation(s) abortedDoes someone has an idea about what's wrong in the scheme file ?Thanks for your help,ced Quote Link to comment Share on other sites More sharing options...
ced Posted August 24, 2009 Author Report Share Posted August 24, 2009 Hi,There was no dc path between node 1 and ground .Adding a very large resistor between both nodes solved the problemGood Bye,C Quote Link to comment Share on other sites More sharing options...
rakeshkoku Posted February 19, 2010 Report Share Posted February 19, 2010 g8 answer ..... Quote Link to comment Share on other sites More sharing options...
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