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Chapter 5 Mechanical and Electrical Power, Work, and Energy 99
FIGURE 5-1 Using a multimeter
Touch one probe to the (+) side of the battery, and one to the (–) side, as shown in
Figure 5-1. New batteries may read up to 1.6V. If it’s an alkaline battery, it will read
closer to 1.3V when drained. If you put the red lead on the (–) side of the battery,
you’ll get a negative number (as shown in Figure 5-1). The reverse is true: if you put
the red lead on the (+) side, you’ll get a positive reading. If you never use your
multimeter for anything else, at least you know how to test for dead batteries now.
Current (I) is the amount of electrical energy passing through a point in the circuit. It is
measured in amperes (A), or amps for short. Using the water analogy, the current at
