I've got a circuit that looks like this:
My input is low voltage AC at low current and I want to measure this with an ADC at 3.3V (eventually, haven't got there yet).
Is this safe/correct? It appears to do what I want when I measure it with my oscilloscope, but it feels strange to me to be sharing an AC line with my DC circuitry (both connect to the same 0V).
I'm having trouble preventing the signal from dropping below 0V. The closest I've got was to connect a schottky with the cathode to signal and the anode to ground. I'm still seeing 300-400mV below zero on the signal line at particular instants. I'm wondering if these things are related.