Re: gEDA-user: newbie opamp blues

[sdb@xxxxxxxxxx (Stuart Brorson)]

> 
> OK, here is the latest. I reviewed opamp-1.sym and opamp-2.sym. Neither 
> one had even a semblance of anything resembling a pin attribute.

Yup.  The important attribute is "pinseq".

> So, I renamed opamp-1.sym and copied in the one you sent in your email.

Good choice.

> Then, using refdes=U1, file=/yadda/yadda/ua741.inc and model=UA741, 
> gnetlist still puts "unknown" into the circuit:
>   XU1 0 2 5 4 1 unknown
>   V1 3 0 DC 2V
>   V2 4 5 DC 24V
>   R1 3 2 10k
>   R2 2 1 40k
>   *vvvvvvvv  Included SPICE model from 
> /usr/src/geda-install/share/gEDA/sym/spice/ua741.inc vvvvvvvv
>   ...etc...

You need to attach a "model-name" attribute to the symbol from within
gschem.  "Model", or any other permutation doesn't cut it -- the
netlister needs a "model-name" attribute.   

Once you get the attributes right, the SPICE line generated should
read something like:  

XU1 0 2 5 4 1 OP07

> So I put it in manually, then run ngspice. Now ngspice is failing big 
> time. I get the exact same errors if I change file to OP07.inc and 
> model=OP07, and put "OP07" on the XU1 manually.

The model-name attribute which gets dumped onto the above line must
match the model's name exactly.  The model's name appears in the SPICE
file after the .subckt declaration:

.subckt 1 2 3 4 5 OP07

> [djlogan@server chapter5]$ ngspice -b problem_5_48.cir -o problem_5_48.out
> Note: trying dynamic Gmin stepping
> Trying gmin =   5.6234E-03 Note: One successful Gmin step
> Trying gmin =   3.1623E-03 Note: One successful Gmin step

[ . . . snip . . . .]

> Supplies reduced to   7.3285% Warning: source stepping failed
> doAnalyses: Too many iterations without convergence

Your simulation is failing because SPICE can't converge.  You know
this already.  Likely causes include a miswired circuit, or some
pathalogical circuit which has e.g. power ground shorts or other
problems.  

Why don't you post your .sch file?

Stuart