In the previous chapters of this book, we learned what we can consider as basic information concerning light-emitting diodes (LEDs), which provides us with a solid foundation for understanding how LEDs work. This information included the basics of p-n junction and emission of both infrared and visible light. In this chapter, we will probe deeper into the manner in which LEDs operate, focusing our attention directly on the operation of a p-n junction. In addition, we will cover two additional LED topics in this chapter that will serve to expand our knowledge of LEDs. The first topic concerns a relatively new type of LED referred to as an organic LED. The organic LED has the potential to make science fiction a reality, with the possibility of having a large-screen super-thin TV that can be rolled up and put away when not in use. The second topic that will be discussed in this chapter concerns the use of an LED driver. Thus, sit back and relax as we continue our exploration of the light-emitting diode.