My room is a comfortable 120VAC, but when I measured for DC, I got the following reading: It changed with each update between positive and negative 220mV or so, taking a few frames to switch all the way.
The reading were kind of like this:
220mV
130mV
40mV
-40mV
-130mV
-220mV
-130mV
etc. etc. Is this bad?