Idahowalker:
For better results measure the 5V of the Arduino. I get 4.977V so I use 1023/4.977I use a MOSFET to gate the voltages on and off.
I have a delay of .09 before I take a A0 reading.
Gives me readings of .005 off my volt meter
Does it stay 4.977volt when e.g. a LED is blinking?
How. Please post a diagram.
Delays do just what they say. Nothing happens during a delay, so why use it.
So 12-15volt with a resolution of 0.005volt (3000 values) from a 10-bit A/D (1024 values).
Leo..