Hi everybody, I'm trying to use an Arduino as a relatively simple go/no-go resistance meter, to measure, for example, if a given circuit is either 2kOhm, 4kOhm, or significantly higher. My question is, can I do this by just sending the 5V through the circuit, and then returning it to an analog input and reading the voltage, which could then be compared to reference measurements?
An acquaintance suggested I'd need to use a voltage divider with resistors roughly matched to the resistance being measured, but I can't quite wrap my head around why that would be necessary in this situation, since I'd only be feeding the regulated 5V max to the input (if it were a dead short). Would that serve to narrow the range/increase the accuracy of the measurement? I almost want to say that it would decrease the accuracy, since less than 5V would be hitting the input at full, so it would never read full, right?
Am I missing something, or was he incorrect?