Light Emitting Diodes are the wonder component of electronic devices. Blinking indicators and light sources in every color of the rainbow make the black boxes of our profession capable of communicating with their users.
Have yours "gone out"? It's easy to forget that these optical devices are fundamentally electrical, and the investigation of their failures follows the same rules as any other silicon-based component, with some important modifications. This article will summarize the function and construction of ordinary LEDs, indicate some common failure mechanisms, and introduce the basic fixes appropriate to each type of failure.