> a couple of quick questions...
>
> I use the 7805 to regulate my 9vdc wall supply to
> +5vdc, but it's off a little. +5.05vdc
>
> I have a 10uf ceramic cap between the +5vdc output
> and ground.  This brings the out put up to +5.05 from
> 4.90 vdc.
>
> ... or is this
> as accurate as these things get?

This is clearly answered in the spec sheet, Duh.  RTFM!

> I don't really care,

Then there is no reason I should either.

> and I don't think this matters does it?

I don't know.  Does it matter if I use a 10K resistor in my circuit?

> But, secondly, I want to know if there is a 780x (2)
> for giving you +2vdc?

This is getting rediculous.  READ THE DATA SHEET before asking stupid
questions.  Yes, I know the answer to this question and the one above.  No,
I'm not going to tell you because I'm training you to look it up yourself,
and I don't want to reward your laziness.

> I have finally gotten back to my AtoD setup using,
> Vss--Vref- and +2vdc--Vref+
>
> it is working fine, using a 200 ohm and 300 ohm
> volatge divider, and that what I will use for now,

Voltage divider from what?  The +5V supply?  In that case the 2V reference
will decrease your accuracy, decrease the range, but increase resolution
within that range.  Also, the divider will draw 10mA.  This is not outright
wrong, but wastes a lot of power unnecessarily.  Compute the impedence of
the divider output.  Now compare that to the Vref+ input impedence.

> I wanted to ask these questions before I forgot, thanks
>
> when talking before about this Vref+ for A/D someone
> mentioned precision voltage sources, is this refering to
> something like the 7805 for +5vdc ??

Unlikely.  A 7805 is generally not considered "precision", but of course
that is subjective and dependent on the application.  I've done a bunch of
designs where the accuracy of a basic 5V regulator was good enough for the
PIC A/D for the particular purpose.


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