How to connect two crossing nets in gaf/gschem

Asked by Marcel Hendrix

Please consider that (1) I have just started to use gschem
on Windows 7, and (2) intend to use it as the schematic
editor for NGSPICE. I am not at all interested in PCB / layout.

All went smoothly up to the point that I constructed a small
test schematic with two crossing nets. With some fiddling
I got a round "cue" dot on the point where the two nets
visually cross.

Converting the schematic to a netlist with spice-sbd was
not a problem, but inspecting the output, I noted that the
two crossing nets are NOT connected together. Closely
reading the documentation it might be saying that two
nets can't be connected where they cross. One can only
connect two nets at their end points, or net1 to the mid
point of another net2. Connecting the endpoint of a third
net to the midpoint of net2 is not possible?
   | |
---x--- 1. <= This is not allowed, do this 2. => ---x--x---
   | |
Version 2 works, but looks unnatural to me.

Version 1 actually constructs ---x--- (two nets connected by a cue),
and a single vertical net that passes through the 'x' cue, but is
not connected to it (!?)

I can approximate what I want by connecting three nets to a pin:
        net b
         |
net a ---x==== pin b
         |
        net c
This is all a bit too hacky for my taste, but I guess I simply
haven't found the correct way to shortcircuit two nets, or maybe
my version of gEDA is too old (gschem 1.9.0, 2011)?

I would love to have a more recent version of gschem, but I did
not succeed to compile it from source with MSYS2 / MinGW 64bit.

-marcel

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Revision history for this message
Launchpad Janitor (janitor) said :
#1

This question was expired because it remained in the 'Open' state without activity for the last 15 days.

Revision history for this message
Bert Timmerman (bert-timmerman) said :
#2

Hi Marcel,

For me this is a bit of a "marmite" question ... you either like it or not ... each to his own preferences ;-)

For me it is a Sound Engineering Principle to not use a connected crossing in a schematic ... you forget the dot, or you place a dot unintentionally ... it's error prone.

Instead I *always* try to use branching connections.

Kind regards,

Bert Timmerman.

Revision history for this message
Marcel Hendrix (mhx-3) said :
#3

On 2018-01-25 20:32, Bert Timmerman wrote:
> Your question #662750 on gEDA changed:
> https://answers.launchpad.net/geda/+question/662750
>
> Bert Timmerman posted a new comment:
> Hi Marcel,
>
> For me this is a bit of a "marmite" question ... you either like it or
> not ... each to his own preferences ;-)
>
> For me it is a Sound Engineering Principle to not use a connected
> crossing in a schematic ... you forget the dot, or you place a dot
> unintentionally ... it's error prone.
>
> Instead I *always* try to use branching connections.

Thanks Bert, I appreciate your help.

It is nice to see this list is still active.

Meanwhile I have found that it is at least *possible* to connect two
crossing nets. Apparently my first try landed me in a situation
in which it is very difficult to make the connection.

-marcel

Revision history for this message
Marcel Hendrix (mhx-3) said :
#4

I learned that by using the Nets Mode button, creating a junction is no problem.