Post-mortem on a penlight

The penlight

The penlight, in its nonfunctional state on the palmrest of my laptop.

My penlight stopped working.

It’s perfectly fine with me; it was a freebie I snatched up from the Michigan Tech Advanced Technologies Development Complex during orientation week. But still…it worked, and then it didn’t. And I wanted to know why.

So I cut it apart.

Turns out that these puppies house an entire triple-A battery inside them! The outside housing of the battery is connected to the negative side of the

The penlight, cut open and splayed out on the table.

The penlight, cut open and splayed out on the table.

battery, so it comes all the way around to the positive side. It has a spring that pushes the battery away from the light bulb; when I press the switch, it mashes the spring and pushes the battery to the light bulb. Except the bulb was burned out. Oops.

Leave a comment