[sdiy] square pads

[ASSI]

On Wednesday 13 October 2010, David G. Dixon 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.

> - the #1 terminal on a pot connector (the one on the right looking at the
> back of the pot)
> - the #1 terminal on a switch connector (the one on the bottom of SPDT,
> or on the bottom right of DPDT, looking at the back of the switch)
> - the #1 pin on an IC

I've only ever seen it used somewhat consistently for marking the 
orientation of parts (#1 pin, mostly).  For some parts it is actually 
difficult to know what pin 1 is since you can get them in different 
orientations that may be mirrored, but that's a minor hiccup.  A lot of PCB 
tools offer the option to give a different pad shape to pin 1, so this is 
easy to do and gets done a lot.  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).

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.


Achim.
-- 
+<[Q+ Matrix-12 WAVE#46+305 Neuron microQkb Andromeda XTk Blofeld]>+

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