yeah so 12 are you basically saying, if I want a voltage signal, and the voltage is not to DRIVE anything (ie circuitry etc) then the amps with that voltage don't matter as much!? this is how I see it..?Didn't mean to ruffle your feathers. I was focused on the idea that some signal measurements work with no current at all, and that is a mistake. It always requires a little bit, sometimes a microscopic bit but, there are no absolute zeros for that answer.
The system is designed to feel the return voltage and convert it into a proper interpretable voltage signal (sine wave) cars do this with everything...