A Variac looks like a sci-fi laboratory prop. For some reason, I have three of them in my shop, and yes, one is just a book end. But they do have a useful purpose.
Variac is a generic trade name for a variable autotransformer. If that doesn't help explain much, let's look at what a regular transformer is, and how they relate to a collection of vintage arcade games.
Five amazing, clean technologies that will set us free, in this month's energy-focused issue. Also: how to build a better bomb detector, the robotic toys that are raising your children, a human catapult, the world's smallest arcade, and much more.