Make Electronics

Switching Basics and More 53

Experiment 6: Very Simple Switching

FundAmentAls

Basic schematic symbols (continued)

Potentiometers suffer from the same inconsistent style be-
tween the United States and Europe, but either way, you’ll
find an arrow showing where the wiper (usually, the center
terminal) touches the resistance. See Figure 2-42. And some-
times LEDs are shown inside circles, and sometimes not. I
prefer circles, myself. See Figure 2-46.

Figure 2-42. Potentiometer symbols: the left is traditional and
used in the United States, the right is European. In both cases
the arrow indicates the wiper (usually the center terminal).

Figure 2-43. Three ways of indicating a pushbutton switch.

Figure 2-44. The battery symbol is usually shown without + and

• symbols. I’ve added them for clarity.

Figure 2-45. Symbol for an incandescent lightbulb.

I’ll explore other symbol variants later in the book. Mean-

while, the most important things to remember are:

• The positions of components in a schematic are not
  important.


• The styles of symbols used in a schematic are not
  important.


• The connections between the components are ex-
  tremely important.

Figure 2-46. Sometimes an LED is shown with a circle around it; sometimes not. In this book, I will include the circle. The arrows
indicate emitted light.