How a Diode Changed My Life
How many of us got one of those Radio Shack 150-in-1 electronics kits as a kid?  (https://www.google.com/search?q=radio+shack+electronics+kits...)It came with a book of projects (e.g. 150 projects and hence the toy's name) and each page had a listing showing the wires you attach from one coiled spring to another.  Hook up different components of the board to make an AM radio receiver, or a "lie detector", or tone generator.Here's the crazy thing.  I ran across an old one 20 years later as an adult and the toy's brilliant idea finally dawned on me:  it allows small children to play with electronics without getting burned by a hot 700 degree soldering iron!  Instead, the child's fingers push the springs apart and he inserts the pre-stripped wires to connect it to another spring.  It was even genius that all the wires it came with were pre-stripped so that even wire cutters weren't necessary.  Everything was also low voltage (9v & 1.5v batteries) so you didn't have to worry about a naked power supply plugged into the wall electrocuting the kid. (E.g. https://youtu.be/9RMKrpzoMkE?t=2m52s)My kit had diodes on it but unlike the author, the toy didn't teach me about them.  Perhaps for others, the Radio Shack kit was a gateway drug to an electronics career.