Hi! I'm experimenting with the Arduino and I'm on the "analog input" page :)
I just can't understand how actually the analog input works from an electrical point of view.
So, the default reference is 5v and that's read to 1024, but how it actually "feels" the voltage applied on the pin?
For example if you ground the PIN analog read report 0, because I assume all the current FROM the pin is drained to ground? But the pin itself is not "outputting" any voltage isn't it?
If you short the pin with the 5v pin you get 1024, how it "feels" those 5v?
Why then if you have GND-----|analog input |-----5v the sensor give 1024 even if it's connect to ground?
Why if I put a thermistor without a resistance the analog input fails to get the correct value and I need to put a 10K ohm resistor before ground it?
I know are probably stupid questions but I cannot find a precise answer on this...