Light bulbs led to the invention of the vacuum tube ("valve") for electronic switching and amplification. All you had to do was put a control grid between the filament and the anode.

One time when I was a kid, someone broke a light bulb. I wanted to look at its innards, but my parents didn't want me to touch it so I wouldn't get cut on the broken glass. I told my dad I wanted to see it, and he pulled it the rest of the way apart with pliers so I could see it.