Makezine_COTM_LED-BadgeCollin Cunningham explains what diodes are all about, describing the history of the component, the various types, and even touches on creating your own.

[M]aking this installment of the series taught me quite a few things. Prior to reading up on the diode, I wasn’t aware how closely its development was tied to the birth of radio – and just how finicky crystal detectors can be. I had a crystal demo in mind for this one, but it seems temperature and humidity hampered efforts to use my newly acquired galena samples.