Digital Multi-Meter (DMM) Guide

Draft - work in progress.

The digital multimeter (DMM) voltage mode has a very high effective resistance, so it senses a voltage without any significant current flowing through the probes. If the circuit attached to a voltage divider has a resistance closer to the values in the divider, then the analysis is more complicated since current also flows out through the output node. Arduino inputs, both digital and analog, have very high resistance and only very small currents flow into them.