Homebrew PCBs

On Sat, 31 Jan 2004 14:39:40 +0000 (GMT), jagjot singh 
<mundasocute2000@...> wrote:

> Hi friends ,
>                I am looking for some very basic information about pcb 
> designing                                                      sunny
>

ALWAYS CHANGE THE SUBJECT LINE OR NOBODY WILL ANSWER!

I have no url or book for you (sorry) because i learned that in school but 
i want to add the following:

These "rules" like 90/45 degree bend etc. sometimes come from only very 
special methods of
manufacturing the pcb (like "acid traps" occur only with tin plating as a 
resist).
Or they are only true for certain applications (like very high frequency).
Always think yourself why you should do things a certain way, and if 
someone says "do it that
way" always ask him why. This also greatly increases the chance that you 
remember it.

Always ask why.

To add some information that may be of use for you:

Track with (minimum) is either determined by the current carrying capacity 
or minimum
track with of pcb manufacturing process, whichever is more.

I use only 45degree bends, because it looks better, but on a pcb are so 
many 90degree edges
(like when 3 tracks join or at each solder pad) that there is not really a 
good reason
for not using 90 degree bends.

Keep the track spacing (and spacing to pads) in mind, it is determined by 
maximum voltage
or manufacturing process, whichever is more.

where to put corners you asked, well, i would say whenever your track has 
to change direction ;-).

Make the solder pads large enough (they have to mechanically carry the 
component),
and make the board "look good". I wrote before, i think routing (and 
placing) is an art.
some disagreed, but i still think so.

If you have questions, feel free to ask, and i hope somebody suggest a 
book or a url.
You may also upload your autotrax design (as a picture) in the files 
section and
maybe some will have a look on it and suggest changes if needed.
We are no "layout verifiers" here but i think this is ok.

Stefan

Oh, yes, if it was not clear above:
ALWAYS CHANGE THE SUBJECT LINE TO SOMETHING MAKING SENSE!