Input bias current?
Common voltage input circuits have a small current leaking out. Could be some fA up to some nA. Together with the input impedance ( R and C here) this results in measurable voltage at the input.
What do you measure with a 10M or 1M (or 50) resistor at the input?
Greetings from Germany
Henrik
LV since v3.1
“ground” is a convenient fantasy
'˙˙˙˙uıɐƃɐ lɐıp puɐ °06 ǝuoɥd ɹnoʎ uɹnʇ ǝsɐǝld 'ʎɹɐuıƃɐɯı sı pǝlɐıp ǝʌɐɥ noʎ ɹǝqɯnu ǝɥʇ'
