> Russell, this is indeed a good introductory issue ! However, I have seen
> an 1Kg kitchen scale, with 8 pF full delta-C variation for the whole 1Kg
> range, and the sensor was connected directly to the microcontroller !.
> The resolution was about 1g and precision about 10g. How they did this ?

Double slope converter and/or balance detector. I have an italian kitchen
scale with 2kg fs and 1g resolution *and* precision (yes, I checked with
many individual small weights). No big deal. The sensor is connected
directly to a micro as far as I can tell. Jeweller's scales work the same
and are even more accurate (50 grams f.s. and resolve 0.01 grams). I
suppose that there is temperature compensation and spring non-linearity
compensation built into the micro somewhere. My scale takes quite a while
to tare. It is very accurate afterwards.

Peter

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