Voltage SelectWhen set to dc voltag

Voltage Select
When set to dc voltage ( ), the meter measures the dc voltage between its V
48 Chapter 2 ■ Voltage and Current
DMMs as Learning Tools
Voltage and current as presented
earlier in this chapter are rather
abstract concepts involving
energy, charge, and charge
movement. Voltmeters and
ammeters are introduced at this
point to help present the ideas in
more physically meaningful
terms. In particular, we concentrate
on DMMs. Experience has
shown them to be powerful
learning tools. For example,
when dealing with the sometimes
difficult topics of voltage
polarity conventions, current
direction conventions, and so on
(as in later chapters), the use of
DMMs showing readings complete
with signs for voltage
polarity and current direction
provides clarity and aids understanding
in a way that simply
drawing arrows and putting
numbers on diagrams does not.
You will find that in the first few
chapters of this book DMMs are
used for this purpose quite frequently.
NOTES...
V (or ) and COM (or
) terminals. In Figure 2–21(a), for example,
with its leads placed across a 47.2-volt source, the instrument indicates
47.2 V.
Current Select
When set to dc current ( ), the multimeter measures the dc current passing
through it, i.e., the current entering its A (or ) terminal and leaving its
COM (or
) terminal. In Figure 2–21(b), the meter measures and displays a
current of 3.6 A.
A