LEDs are everywhere. Over past years they’ve crept into our cell phone screens, the headlights on our cars, the display boards in our favorite sports stadiums, and even into our household light sockets.  With their minimal energy consumption and extra-long rated lives, these babies are on the rise. But in this heyday of LED innovation, have you ever wondered how they came about?

Disclaimer: the history of LEDs is crazy.

(But what would you expect for a light source that we use to light our streets at night AND zap the tattoos off our arms?)

In the beginning was Henry J. Round, a British experimenter at Marconi Labs. In 1907 he was unsuspectingly at work on a cat’s whisker detector for radio made with carborundum (SiC) when suddenly he witnessed a yellowish light—and lo! it was electroluminescence. With increased voltage the light turned brighter yellow, then green, orange, and finally blue. Round was so stoked he wrote a letter to Electrical World about it, and then went back to his radio. Continue reading »