I’ve started a little summer project with building a quadcopter using an Arduino Uno R3 (original, eh?).
Anyway, seeing as the whole thing will be running on a lipo battery I want to monitor the battery voltage. I’ve done some research and the current plan is to make a voltage divider to bring the 12V down to around 1.1V and feeding it into an analog input. And as you may have guessed I’ll read the analog input using the internal 1.1V reference voltage (which I have already measured to be 1.082V).
Now, to the question, what happens if I apply a voltage above 1.1V to an analog input? The reason I ask is that I’ll be running an I2C device on the A4 and A5 pins, which will be running at 5V. I am new to electronics and I’m unsure whether using the internal reference of 1.1V will cause a reverse current when you apply 5V on the pins and whether or not it will be damaging.
Thanks in advance