@crami25 Thank you very much for this information. I have improved with the capacitor, without changing the potentiometer (I only have that at hand). I'm using the range adjustment at 1.5 v ( ADC_2_5db) and making analogSetSamples(16) , I get this dispersión that would be by 0.2%. It's all right. I'll keep testing, Greetings.
0_1586771570602_dispersion.PNG