I am making a test fixture to detect +-100mV RMS sine output. Can Arduino Leonardo do this or do I need a voltage sensor? Mark from Integrated
None of the Arduinos can handle -ve voltages
Check the product notes does the Leo have an ADC
If does, then you can read it but 100mV won't give much by the way of resolution so you may need an amp.
Find a way of checking if its a sine wave (assuming you have sorted all the above)
You have to tell us more about the signal. Is it an output of a current clamp or current transformer ? Is it mains AC ? 50Hz or 60Hz ? or an audio signal ? What kind of accuracy do you need ?