I have an external circuit that uses the digital pins 2 and 3 of the Arduino. I said Arduino because connecting the circuit to these two pins of the Arduino Uno, everything is working fine and the Serial Monitor prints the correct result, while, if I plug it to my Yun, nothing happens. Actually, with the Serial monitor opened, when I plug off the the two wires from the Yun's pins, the Serial monitor prints something interpreted as 0.
I don't know if I expressed well myself but it is like if the pins are blocked and they react only when the signal is not there anymore (when I plug off the wires).
Why do I experience this different behavior between the Yun and the Uno?