On Fri, 8 Mar 2002 14:21:12 -0500 Spehro Pefhany writes: > Yes, assuming the sensor to be linear! If you're digitizing this > it's often > best to use a single reference voltage for both the A/D and the > sensor. If > you have a clean enough supply voltage of high enough accuracy, that > reference may be the supply voltage (as can be done with PIC A/Ds). > Then > the reference voltage cancels and you'd get a count of 0x200 +/- > from a > 10-bit A/D at half-scale (output voltage, maybe input pressure) > regardless > of the exact reference voltage. > That DOES make ratiometric transducers nice. As long as the A/D and the transducer are using the same reference, it can be a CHEAP reference (like a 7805) and you don't lose any accuracy. Saves pins on the PIC too (since you don't need to have a reference pin)... Harold FCC Rules Online at http://hallikainen.com/FccRules Lighting control for theatre and television at http://www.dovesystems.com ________________________________________________________________ GET INTERNET ACCESS FROM JUNO! Juno offers FREE or PREMIUM Internet access for less! Join Juno today! For your FREE software, visit: http://dl.www.juno.com/get/web/. -- http://www.piclist.com hint: The list server can filter out subtopics (like ads or off topics) for you. See http://www.piclist.com/#topics