[Help-gnucap] Short circuit current and resistance?

[Philip Jägenstedt]

Hello!

I recently used gschem and gnucap to verify my homework in electronics 
(yes, I got it right). However there are two things I can't really 
figure out how to do, I suspect they are not terribly difficult and I'd 
like to know. I've done some reading in the manual, but it didn't help 
me a great deal. Attached is the gschem file and the file generated by 
gnetlist that I used to verify my homework.

1) If I want to see what the current through a branch which short 
circuits the open section to the right in my figure (i.e. short 
circuiting nodes 8 and 6 in the netlist), how would I do that? What I 
did now was I hacked it by adding a 0 ohm resistance, but I didn't think 
that was a very pretty solution. Since a short circuit doesn't show in 
the netlist as a component, I can't measure the current through it by 
any obvious method.

2) I'd like to measure the resistance over the two nodes in the open 
section to the right in my figure. I could get this by dividing the open 
circuit voltage over short circuit current (and this is what I did to 
get the answer for my homework) but I'm wondering if it's possible in 
some other way to measure the resistance between any two nodes in the 
circuit).

Thank you!

// Philip Jägenstedt

*********************************************************
* Spice file generated by gnetlist                      *
* spice-sdb version 12.29.2003.c by SDB --              *
* provides advanced spice netlisting capability.        *
* Documentation at http://www.brorson.com/gEDA/SPICE/   *
*********************************************************
I01 6 8 3m
I02 5 9 2m
R1 9 2 12k  
R10 1 8 2k  
R2 2 3 19k  
R3 5 4 1.5k  
R4 3 4 5.5k  
R5 2 1 3.5k  
R6 3 1 2.5k  
R7 7 6 3.5k  
R8 5 6 6k  
R9 1 6 13.5k  
V1 4 7 3
V2 2 3 6
.END

v 20040111 1
C 51100 59400 1 0 0 resistor-1.sym
{
T 51400 59700 5 10 1 1 0 0 1
refdes=R5
T 51400 59200 5 10 1 1 0 0 1
value=3.5k
}
N 52000 59500 54900 59500 4
N 54900 59500 54900 58600 4
N 51500 58600 51500 57800 4
N 51000 58600 51000 57800 4
N 51000 57800 50700 57800 4
N 50700 58600 52600 58600 4
N 49800 58600 49400 58600 4
N 49800 57800 49400 57800 4
N 49400 57800 49400 59500 4
N 49400 59500 51100 59500 4
N 49400 58600 49000 58600 4
C 52600 58500 1 0 0 resistor-1.sym
{
T 52900 58800 5 10 1 1 0 0 1
refdes=R6
T 52900 58300 5 10 1 1 0 0 1
value=2.5k
}
C 49800 58500 1 0 0 resistor-1.sym
{
T 50100 58800 5 10 1 1 0 0 1
refdes=R2
T 50100 58300 5 10 1 1 0 0 1
value=19k
}
C 51400 57800 1 270 0 resistor-1.sym
{
T 51000 57400 5 10 1 1 0 0 1
refdes=R4
T 51700 57200 5 10 1 1 0 0 1
value=5.5k
}
N 51500 56900 51500 56200 4
N 49400 56200 49400 55400 4
N 49400 55400 51100 55400 4
N 52000 55400 54900 55400 4
C 50000 56100 1 0 0 resistor-1.sym
{
T 50300 56400 5 10 1 1 0 0 1
refdes=R3
T 50300 55900 5 10 1 1 0 0 1
value=1.5k
}
C 51100 55300 1 0 0 resistor-1.sym
{
T 51500 55600 5 10 1 1 0 0 1
refdes=R8
T 51500 55100 5 10 1 1 0 0 1
value=6k
}
C 53700 56100 1 0 0 resistor-1.sym
{
T 54100 56400 5 10 1 1 0 0 1
refdes=R7
T 54000 55900 5 10 1 1 0 0 1
value=3.5k
}
N 50900 56200 52100 56200 4
N 53700 56200 53000 56200 4
C 54800 57800 1 270 0 resistor-1.sym
{
T 54500 57300 5 10 1 1 0 0 1
refdes=R9
T 55100 57300 5 10 1 1 0 0 1
value=13.5k
}
C 55400 58500 1 0 0 resistor-1.sym
{
T 55700 58800 5 10 1 1 0 0 1
refdes=R10
T 55800 58300 5 10 1 1 0 0 1
value=2k
}
N 53500 58600 55400 58600 4
N 54900 58600 54900 57800 4
N 54900 56900 54900 56200 4
N 56700 57900 56700 58600 4
N 56700 56200 56700 57000 4
N 54600 56200 57900 56200 4
N 56300 58600 57900 58600 4
N 54900 55400 54900 56200 4
C 52100 56000 1 0 0 voltage-3.sym
{
T 52200 56500 5 10 1 1 0 0 1
refdes=V1
T 52800 56500 5 10 1 1 0 0 1
value=3
}
C 49800 57600 1 0 0 voltage-3.sym
{
T 49700 57500 5 10 1 1 0 0 1
refdes=V2
T 50500 57500 5 10 1 1 0 0 1
value=6
}
C 56900 57000 1 90 0 current-1.sym
{
T 56500 57200 5 10 1 1 180 0 1
refdes=I01
T 56200 57600 5 10 1 1 0 0 1
value=3m
}
C 47900 57000 1 90 0 current-1.sym
{
T 48300 57700 5 10 1 1 180 0 1
refdes=I02
T 48000 57200 5 10 1 1 0 0 1
value=2m
}
N 48100 58600 47700 58600 4
N 47700 58600 47700 57900 4
N 47700 57000 47700 56200 4
N 47700 56200 50000 56200 4
C 48100 58500 1 0 0 resistor-1.sym
{
T 48400 58800 5 10 1 1 0 0 1
refdes=R1
T 48400 58300 5 10 1 1 0 0 1
value=12k
}