Lesson 3/Learning Event 1
FIGURE 22. AMMETER OPERATION.
The ammeter must be placed in the electrical circuit in such a way that all the current flows
through it. It is necessary to break the circuit and connect the ammeter into it. The electrical term
for this type of connection is series. A series circuit is one that has only one path or wire through
which the current can flow.
An ammeter is always connected in series so it can measure the total amount of current (amperage)
flowing. Figure 22 shows the right way to install an ammeter.
There are three general types of ammeters.
The first type is used in the instrument panel of some automobiles and trucks. This particular
ammeter can be identified by the zero in the center of the scale and equal numbers to each side of
the zero. A minus or negative symbol (-) or the word discharge is located at the far left of the
numbers. A positive symbol (+) or the word "charge" is located to the far right of the numbers.
This ammeter shows the operator whether the battery is charging or discharging.