Use a three resistor setup: one resistor to the +5V connected to another
resistor to ground.  Add the third between the voltage you want to measure
and the common node of the other two.  Use algebra to calculate the needed
values.

-----Original Message-----
From: pic microcontroller discussion list
[mailto:PICLIST@MITVMA.MIT.EDU]On Behalf Of Dennis Oliver
Sent: Friday, August 17, 2001 12:33 PM
To: PICLIST@MITVMA.MIT.EDU
Subject: [PIC]:


I am trying to figure out a way to measure a DC voltage that ranges
from -0.9V to +12.5V.  I ideally would like to just add 1V to the signal,
and then use a voltage divider to get it to the 0 to +5V range of a PIC.
How do I condition the signal???

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