Re: gEDA-user: Hi.... first post

["C P Tarun" <tcpip@xxxxxxxxxxxxxxxx>]

Thanks, all of you. I really appreciate the help. Am feeling a lot
more relieved.

I now realise that just like I like my own resistors and capacitor
footprints more than the ones I found in the PCB libraries, I will
probably need to build my own edited collection of gschem symbols.
I can live with that. :)

> geda and pcb don't care if the pinnumbers are numbers or strings. As
> long as they are the same.
>
> From a preference point of view I like the pin numbers to match the
> component data sheet.

This is the part I too would have thought was natural. I would have thought
that "B", "C", and "E" were more sensible pin numbers in the symbols
than "1", "2", and "3".

Also, I have read the section about transistor pin mapping between
symbol and footprint here:

  http://geda.seul.org/docs/current/tutorials/gsch2pcb/transistor-guide.html

The author specifies two schemes for achieving this, and chooses one.
I would have thought a third scheme would be better, where all transistor
symbols have pins labelled "B", "C", and "E", and there will be different
versions of the TO92 (or TO5 or whatever) footprint, called "TO92-EBC",
"TO92-CBE", and so on.

I see this as a more natural way to implement this mapping. This is
because there can be no controversy about the pin names in a schematic,
because the _diagram_ itself tells me which is the base, which is the
collector, etc. I don't want six different types of symbols at the schematic
stage, because there is no controversy about the semantics of these
symbols. All the controversy is at the package stage, therefore I should
have different versions of the footprint, I would have thought.

Anyway, I guess this has been debated hotly and much more experienced
designers and engineers must've figured out the best way to do this. I
was just adding my ten-paise worth of perspective, heavily coloured
by the way Eagle does things.

What is the general opinion about keeping symbol pin numbers for
transistors as "B", "C" and "E"? Isn't this better?

Tarun


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