[sdiy] Design Process

[David G. Dixon]

> ...The second board
> is almost always a keeper.  Only very rarely do I have to make a second
> revision, and then usually because I've overlooked some subtle issue of
> circuit design of which I was not aware; never because of layout error.

I should also add that, now that I have a fair bit of practice doing this,
even layout errors are very rare in my first boards.  The reason for
revising the first board is almost always to address some circuit design
issue that I hadn't thought of.

What typically happens is that I design (or adapt) a circuit, make the PCB
and test it.  Then, I discover some minor (or sometimes major) deficiencies
because of something I hadn't thought of or didn't know about (or forgot, or
failed to note on a datasheet).  Then, I will rethink those parts of the
circuit which need rethinking, often coming to this list (or one or two
trusted gurus thereon) with questions.  Then I incorporate the improvements
into the second board, which is almost always perfect.  With luck, this
entire process takes just one day.