If you’re testing old stereo equipment, a dim bulb tester can really come in handy. 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. Just be wary — you need to know what you’re doing with mains voltages to do this safely!
This is a companion discussion topic for the original entry at https://hackaday.com/2024/01/18/a-dim-bulb-tester-is-for-testing-other-equipment-not-bulbs/