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.
For example, you can insert a voltmeter into the LED circuit so that you can measure voltage. In this case, the voltage is measured across the battery. To measure voltages in the LED circuit, spin the multimeter dial to a range whose maximum is at least 10 V. Now just touch the leads to different spots in the circuit.