Visit the Spark Museum for some Steampunk vintage radio/electronics fun. It includes a picture on one page of a device I actually own, bought for 5 dollars at an estate sale from people who didn’t have a clue what the weird stuff in the back of their grandfather’s attic was. I figured it was a prize for the brass rotary voltage adjuster in the oak box, the ingenious wiring harness that allowed it to add another battery for each step you turned it up, and the full set of original 1924 RCA batteries (none leaking, and a few that could still hold a charge). It wasn’t until I got it home and did some research that I discovered what it was actually supposed to be. A word of caution if you find one of your own; it can get slightly painful if you crank it up beyond eight batteries in the circuit (You didn’t think I skipped the refurb and test part of the process, did you? What fun would that be? One should always get the full experience).