Working with Diodes and LEDs
In This Chapter
Sussing out how semiconductors work
Introducing the simple diode
Changing AC to DC with diodes
Lighting up with LEDs
From roughly 1900 to 1950, the world of electronics was dominated by a now all but obsolete technology: vacuum tubes. These glass tubes were large, expensive and fragile and required a lot of current. In the 1940s, however, researchers made a technological breakthrough, which led to new components that were a quantum-leap improvement over vacuum tubes. These components are called semiconductors.
This chapter introduces you to the most basic kind of semiconductor, called a diode. Although diodes look a little like resistors (for details, check out Chapter 2 of this minibook), they behave very differently. Diodes have one ability that sets them apart: they let current flow freely in one direction, but block current if it tries to flow in the other direction. In other words, a diode is like a turnstile gate that you can walk through in one direction but not the other. This characteristic turns out to be incredibly ...