gEDA-user: ngspice transfer function

[cedric <cedric_libre@xxxxxxx>]

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 




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