It’s not for testing bulbs, though, it’s a tester that uses a dim bulb to test other things. [Nicholas Morganti] explains it all in his guide to making your own example of such a tool.

Plugging in something like an antique radio to see if it works is a good way to have a bad time, because some old components don’t age well. For vintage electronics, inspection and repair are… ...

The similar, but non-dimmable bulb, was previously billed as the "world's most energy efficient light bulb." That project raised $273,278 on Kickstarter last year and delivered over 7,000 bulbs to ...