Let There Be Light! Build a Reading Light That Switches On when It Gets Dark
YOU MAY HAVE A SECURITY LIGHT OUTSIDE your house that switches on automatically when it gets dark. This type of light has two main purposes: It provides illumination outside your house to make it more secure at night, and because it is automatic, you don’t have to remember to switch the light on and off. In this experiment, shown in Figure 16-1, you’ll learn how to make a circuit that acts like this type of security light. It could be used as a small reading light that switches on automatically when it gets dark.
FIGURE 16-1 The reading light
You’ll learn ...