Does the Arduino Capacitive Sensing Library fully charge/discharge the "capacitor"?

Question

I'm currently trying to figure out how the Arduino Capacitive Sensing Library works. There is already a similar, but more general question: How does the Arduino CapSense library work? The answers there explain that it's a RC circuit and therefore, there is a RC time constant which depends on the capacitance C. So if C changes - i.e. a human finger is in proximity of the sensor metal plate - there is a different time measurement.

Source: https://playground.arduino.cc/Main/CapacitiveSensor/

• Does this "capacitor" (sensor metal plate + human finger) get fully charged/discharged? (What does that even mean in this context?)
• I'm thinking yes because if I'm imagining a huuuuge sensor plate that can store lots of charge, wouldn't that be like shorting it to GND? Then, the input pin would never change.
• How important are the additional capacitors "to improve stability"?

Answer 1

No, the capacitance does not need to be fully charged for the input pin state to change.

The capacitance only needs to charge enough that the input pin voltage crosses the input logic threshold voltage to change the state to logic 0 or to logic 1.

Answer 2

it only puts enough charge in/out for the input pin to change its reading.

Even a huge capacitor will eventually charge up or discharge, if it's taking too long use a lower resistance for R