Maybe I'm doing something wrong, but here's what I'm trying to do.

I'm trying to measure voltage of a battery that can go as high as 16V. I'm
using RA0 set as analog input for the A/D and I'm using Vdd as a reference.

In order to reduce the voltage to compatible levels, I've connected the
following voltage divider: from the + side of the battery, I have a 4.7K and
then a 2.0K in series going to the - side. Let's say that the battery has
12V across poles. I put my multimeter + probe in between the two resistors
and the - probe on the - of the battery. It reads about 3.6V, perfect.

Now I connect my circuit's ground to the ground on the battery to be
measured, still 3.6V. The problem happens when I connect my RA0 pin to the
divider (same spot where my probe is). Immediately the voltage drops to
2.65V.... why is that? 1V doesn't seem a lot but when I do the math to
output the real battery voltage, of course it doesn't match anymore.

What am I doing wrong?

I measured the voltage accross RA0 and ground, it is not zero. I figured
that perhaps it is because the pin is set as input and is floating?

Help is very much appreciated

Padu

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