[sdiy] PCB Layout terminology

[Tony Clark]

   Hi Elby,

> Some of them look like they might be quite usable,
> but I'm getting hung up on not knowing the lingo.  I'm no longer scared off
> by part numbers like "2N3904" (I seem to be getting quite friendly with these
> guys in fact), but suddenly I'm now confronted with designations like TO-92
> (I *think* that goes with the 3904!).  I can't figure out how to go from the
> parts list/schematic to these layout designations.  Are there "translators"
> available?  A good website, perhaps?

   Well I don't know about translators, but you may just have to do what 
most of us do and download the data sheets.  All data sheets will usually 
give a list of available "packages" that the part comes in.  For 
instance, a 741 op-amp might be available in an 8-pin DIP, or an 8-pin 
SOIC, or even a 8-pin TO-99 metal can!  The data sheet will let you know 
(at least for that particular manufacturer) what the case (package) style 
is and what the pin order is.  The pin order is usually set for most 
parts, but transistors can vary quite a lot!  So be sure to watch out for 
that!
   For instance, if you have a TO-92 transistor with 3 pins,

   is it:

    BCE
    BEC
    CBE
    CEB
    EBC or
    ECB?

   This is what annoyed me about hunting around for PCB software.  Some 
of the ones I tried just gave you a plain transistor model with no 
variations for the above!  Makes it a royal pain when translating from 
schematic to layout!
   Good luck with your search.

   Tony

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