Re: The input stage: almost done!

From: sleeper75se (sleeper75se_at_yahoo.se)
Date: 2002-01-23 10:14:27


Hi,

design and layout of the input stage is complete. Finally (phew).

A PDF-file with schematics, parts list and layout can be downloaded
from the files section as usual:
http://groups.yahoo.com/group/buildcheapeeg/files/hardware%
20design/TinyEEG%20-%20SMT/

Note: The page format is the european A4, which is slightly narrower
and longer than the US Letter format. Be aware of this if you print
the artwork, so that the pages are not rescaled. This is usually not
a problem though.

Final tweaks:

* I did another round of searching for capacitors and found SMD
polyphenylene sulfide (PPS) caps. They are made for filter
applications and come in much larger capacitances, so the resistors
are reduced to more reasonable (< 50k) resistances. Precision is
better too (2%), at lower cost.

* The highpass filter caps in X7R material are replaced with a pair
of back-to-back tantalums.

/Andreas



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