I am trying to connect voltage divider to ADC,
The resulting circuit is similar to
But
R1,R2 - 870Kom (I need low power consumption, because of battery powered device).
C1 - 100nF. ( As in ESP recommendations)
As a result, R2 + C1 gives RC oscillator, which oscillate at 1.8Hz
So the resulting voltage measurements have dispersion around 0.4 Volt.
When I log to console raw measurments in cycle, I can see real sinus.
How to correctly connect voltage divider to ESP without such effects?