Re: Microchip PIC programming question

In article <aKGdnd66zr5K2E3fRVn-uw@xxxxxxxxxxxx>, jpopelish@xxxxxxxx
says...
> That means, if you try to digitize your 30 millivolt signal, the A/D
> converter won't be able to distinguish it from 34.9 mV.
>
> However, if you multiply this voltage by a fixed gain with an opamp,
> (say, 50 times) so that the maximum value is closer to the PIC supply
> voltage, the resolution will more closely approach the full .1% the
> converter is capable of.

And the PIC A/D converter is a leaky piece of crap. When they say
input impedance should be < 2.5K, they aren't kidding. You often
need a buffer amp even if the input signal is at a reasonable level.
And don't even think about driving an input above the supply rail,
because this makes all the other inputs leak even worse than spec.

.

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