I'm currently looking at the Arduino Pro Mini schematic and have noticed that the pin AREF (analogue reference) is connected to a 0.1uF capacitor as shown below:
I have done some research and read this great explanation into AREF and now understand its purpose as a voltage reference. What I do not understand however is the purpose of the capacitor. Is it as a means of stabilising the pin when an external voltage is applied, or something else?
A full schematic of the Arduino Pro Mini can be sourced from here.