I’m going to break from the typical Hackaday article format for a moment. I’m smitten, captivated by this wondrous new discovery. Forgive my ignorance for having never seen one of these before, I didn’t go to school for electronics. For those, who like myself wondered, what is this beautiful glowing thing, it is a mercury arc valve rectifier.
This is not some chintzy attempt at neo victorian styling (steampunk if you absolutely must), this is an actual piece of electronics used in the field. Widely used to convert alternating current to direct current for railways and street cars, these could actually be found in the wild. There was a time, that opening a door in a power station would have presented you with this fantastic green and purple glowing orb, dripping mercury sparkling inside. If you are anything like me, you would most likely have been frozen in your tracks, convinced you were bearing witness magic.
A diode allows current to travel in only one direction. With that in mind, [Alex] built a mechanical diode that will only allow gear rotation in one direction to be transmitted through the system. But wait, by connecting two of these devices together he’s built something of a mechanical rectifier. An electrical rectifier converts alternating current to direct current and this mechanical version outputs clockwise rotation no matter what direction of rotation is coming into the device.
There’s video which we’ve embedded after the break as well as many pictures on his site but not much explanation. Here’s what we’ve deduced. The two large gears are inputs. Mounted on top of them is a smaller ratcheting gear that will only turn in one direction. This ratcheting gear selects whether the smallest gear on the left or right will rotate, which then feeds the output gear at the top of this image. Continue reading “The mechanical diode”