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The circuit shown in Figure 5-1 has just two components: a battery and a lamp. Most electronic circuits will have additional components. There are hundreds of different types of electronic components, and each has its own unique schematic diagram symbol. Fortunately, you need to know only a few basic symbols to get started. These symbols are summarized in Table 5-1. (Note that when used in an actual circuit diagram, the symbols are often rotated.)

Figure 5-3 shows a schematic diagram that includes several of these components. Don’t worry — you don’t need to understand this diagram right now. I just want you to get an idea of what real-world schematic diagrams look like and how to read them.

TABLE 5-1 Common Symbols for Schematic Diagrams

Symbol	Description
	Battery
	Capacitor
	Diode
	Ground
	Inductor (coil)
	Lamp
	Light-emitting diode
	Resistor
	Source voltage connection
	Speaker
	Switch
	Transformer
	Transistor (NPN)
	Transistor (PNP)
	Variable resistor (potentiometer)

As you can see, the circuit shown in Figure 5-3 contains six components. Working from left to right, they are:

 6 V battery

 NPN transistor

 Resistor

 Capacitor

 PNP transistor (at the top right)

 Light-emitting diode (at the bottom right)

FIGURE 5-3: A typical schematic diagram.

Throughout the course of this book, I use these and other symbols in the schematic diagrams that describe the circuits. Whenever I use a symbol for the first time, I explain what it is and how it works.