[sdiy] moving to SMD/SMT

[Tony Clark]

   Hi John,

> Roman, I must say that it struck me as funny that you wrote, "...
> decide up front on one size of components. I'd suggest 0805. They are
> easily to handle and not so large and bulky as 1206."
> 
> So, now we're calling some SMDs as large and bulky?!  ;-)

   Well howabout expensive, then?  1206 parts usually cost more, but not 
too bad.  BUT!  Be sure that you use the correct sized part for the 
amount of current that you plan to be drawing!  IE, watch those wattage 
ratings!  0805's are only 1/8 watt, 1206s are 1/4 watt.  1210's are also 
1/4 watt but tend to cost 3 times as much as 1206's!
   Want to know what happens when you exceed the wattage rating on a chip 
resistor?  It tends to explode, lauching itself straight off the PCB!  Or 
they tend to crack in two (and you may not notice, except when measuring 
across the part with a meter!).  You might consider this a safety feature, 
since they don't tend to char and burn like thru-hole varieties.  :)  
Good for the PCB, at least.

   Cheers,

   Tony

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