Final answer:
The AREF pin on the Arduino UNO is used to provide a Reference voltage for analog inputs, which sets the upper limit for analog-to-digital conversions.
Step-by-step explanation:
Function of the AREF Pin on the Arduino UNO
The AREF pin on the Arduino UNO is used as a Reference voltage for analog inputs. This pin allows the user to feed a reference voltage to the Arduino which is then used to set the upper limit for the analog inputs in analog-to-digital conversions. By default, the Arduino boards are set up to use an internal reference voltage, but if more accuracy or a different range of input voltages is required, an external reference voltage can be applied to the AREF pin.
This is critical when dealing with various sensors and analog signals that may not align perfectly with the default reference voltage. It is important to note that the reference voltage applied to the AREF pin should not exceed the recommended voltage level as specified in the Arduino's datasheet to prevent damaging the microcontroller. Let's mention the correct option in the final answer: The AREF pin on the Arduino UNO is used for the Reference voltage for analog inputs (Option B).