[sdiy] square pads

[cheater cheater]

On Wed, Oct 13, 2010 at 21:09, David G. Dixon <dixon at interchange.ubc.ca> wrote:
>> > Here's a dumb question:  What does a square pad on a PCB mean?
>>
>> The Humpty-Dumpty answer:

:)

>> It means what I chose it to mean, nothing more or less.
>
> Hmmm.  Not the answer I expected.  Isn't there even a hint of a standard?
> The square +V connector pad is used by several prominent builders (Jurgen
> Haible and Ken Stone, to name but two).

Haha, Jürgen is a Promi, like Katzenberger :)) Except doesn't look as
good in a Dirndl :)

>> As long as you are consistent and explain
>> it in the build instructions it would certainly be helpful especially on
>> home-made PCB (no silk screen).
>
> Yes, my motivation exactly.
>
>> I'd be leery of a "that pad shape means (+)" convention though, there
>> should
>> be enough room next to the power connector to just have the labels in
>> copper
>> and remove any doubt.  The same goes for pot connectors (if they can be
>> oriented in reverse or you just provide wiring points for panel pots).  If
>> you want to be really nice to your kit builders, try to orient everything
>> of
>> the same type in the same direction and leave enough space between the
>> parts.
>
> Well, for panel pots, I've decided that one really must provide decent
> instructions, at least for my boards.
>
> Concerning orienting ICs, I line them all up straddling the power rails, so
> I always orient them with the +V pin on the same side.  This means that most
> quad opamp chips are upside down relative to most other chips.  Hence, the
> desire to use square pads for some clarity.

For those upside-down things it's quite useful to have a silk screen
that shows which way the notch should be. Also, it's very very useful
to have a drawing that shows which way the components should be
oriented. It makes it easy to check your build that one last time
before you power it up. You can't get that smoke back in.

Cheers,
D.