FIGURE 12.

BASIC FLASHLIGHT SCHEMATIC.

To construct any graph of electrical quantities, it is standard practice to

vary one quantity in a specified way and note the changes which occur in a

second quantity. The quantity which is intentionally varied is called the

independent variable and is plotted on the horizontal axis. The horizontal

axis is known as the X-axis. The second quantity, which varies as a result

or the changes in the first quantity, is called the dependent variable and

is plotted on the vertical or Y-axis.

Any other quantities involved are

held constant.

For example, in the circuit shown in Figure 13 (on the following

page), if

the resistance was held at 10 Ohms and the voltage was varied, the

resulting

changes in current could then be graphed. The resistance is the

constant,

the voltage is the independent variable, and the current is the

dependent

variable.