How They Work: Blinking Christmas Lights

Have you ever wondered how the little blinker bulb makes an entire strand of lights blink? No? Well these are the random things I think about in the middle of the night when hubby didn't unplug the Christmas lights outside and I can't fall back asleep because of the blinking lights I can see out my bedroom window.

And when I am too cold to go outside myself (or maybe just too lazy) to turn them off, I get up and Google my question so that I can learn something new (and useless).

The extra piece of metal at the top is a bi-metallic strip (see How Thermometers Work for details on bi-metallic strips). The current runs from the strip to the post to light the filament. When the filament gets hot, it causes the strip to bend, breaking the current and extinguishing the bulb. As the strip cools, it bends back, reconnects the post and re-lights the filament so the cycle repeats. Whenever this blinker bulb is not lit, the rest of the strand is not getting power, so the entire strand blinks in unison.

So moral of the story, if your lights aren't working and they blinked last year, check that bulb first! And go about your day feeling a little smarter because you now know how that little red tipped blinker bulb works. And if you already knew, then go about your day feeling smarter because you knew it and I didn't!

PS: The info from How Stuff Works. I didn't just make it up! Promise.