[sdiy] square pads

David G. Dixon dixon at interchange.ubc.ca
Wed Oct 13 21:09:29 CEST 2010

> > 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).

> 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.

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