Eye Strain. When you stare at screens all day, your eyes can get tired. Take a break with the 20/20/20 rule. Look at an object at least 20 feet away for 20 seconds every 20 minutes, says Ivan Schwab, MD, a spokesman for the American Academy of Ophthalmology.
Once you have the dial on your volt meter set to measure voltage, simply touch the black lead to the negative (-) terminal on your battery and the red lead to the positive ( ) terminal on your battery.
One volt is defined as the difference in electric potential between two points of a conducting wire when an electric current of one ampere dissipates one watt of power between those points.