 As the name implies, a multimeter can measure all sorts of electronic signals and parts. Everyone should know how to use one. Start with measuring voltage from a battery. Make sure the black test lead is connected to the common ground jack, and they're read to the jack labeled V. Set the meter to the voltage setting. If there's multiple V modes, choose the one with straight and dotted lines. That's DC voltage. The other curvy line symbol is for AC voltage. To test a battery, touch the tip of the black lead to the battery's negative terminal, and the red lead to the positive terminal. So this 1.5 volt battery is supplying about 1.67 volts, which means it's nice and fresh. And this 1.5 volt cell can supply about 0.267 volts. Wow, that is impressively low. This one is done.