App note: Analog sensor signal conditioning circuits

An analog sensor outputs a voltage relative to whatever it measures, as opposed to digital sensors that provide the reading as a number. These voltages sometimes need to be conditioned to be useful. Microchip describes various analog sensor conditioning circuits:

Analog sensors produce a change in an electrical property to indicate a change in its environment. this change in electrical property needs to be conditioned by an analog circuit before conversion to digital. Further processing occurs in the digital domain but is not addressed in this application note.