I connected two 100k resistors in series between GND pin and +5V pin.I connected the ADC A4 pin at the the middle. AREF = DEFAULT(+5V). But the ADC did not read 512 units. Instead it kept fluctuating between 506 to 508 units. What must be the reason for this weird behavior ?
Note - Arduino Uno was powered by 12V AC-DC power adapter.
Note - Arduino Uno was powered by 12V AC-DC power adapter.