Using audio input to measure voltage.

[WitoldW]

Anybody can help?

 

[Mikestony]

Please clarify?
Audio input such as the built in mic? What device? Measure voltage of what in particular? AC or DC voltage?

 

[mikedt]

You can probably measure the amplitude of the signal coming in, it is an AC voltage. There's various scope and VU meter apps already, and that's what they do. A similar app calibrated in volts could probably be made. How accurate it would be though, don't know, might depend on what phone it is.