Explain me, please, is there any basic difference between a shunting of a signal by means of the capacitor and a low-frequency filtering.
If to switch on the capacitor on an entrance of an operational amplifier, can we count it certain low-pass filter? TIA
A capacitor from signal path to ground forms a simple low-pass filter, in conjunction with the source impedance feeding it - as this is generally not known, may change, and may be very low anyway, it's normal to have a series resistor in the signal line. This swamps the source impedance, and allows you to use that value, and the capacitor's value, to calculate the turnover frequency.