I've never found any advantage to ratcheting screwdrivers but I've bought them a couple of times for the one odd tiny star bit I needed at the time. I've owned a few Yankee screwdrivers too, nice tools but I seem to prefer to do my own ratcheting, as opposed to fiddling with the forward/ reverse switch. The light bulb limiter though, I just dug out an actual old variac I've had for years but never wired up. Looking on ebay for an analog voltmeter, but guessing the voltage numbers on the variac dial are adequate. Or I can check with a multimeter if using it to break in a speaker. The bigger issue is there are five connections labeled 1 2 3 4 and 5, and I don't know what any of them are. I suppose two are the primary winding and two are the secondary, plus a ground for whatever reason? Effectively a great tool but I don't know how to use it! Might be partly putting off doing a recap on a big old Sound City Hiwatt sort of thing that doesn't work, and that needed a recap and probably a PT when it was last working. PT seemed to be the source of a constant crackling, not heard through the speakers. I found a correct used PT for it a couple of years ago and finally bought new filter caps recently. I'm lousy with electronics and have a bad record with fixing stuff that has multiple undiagnosed problems. Charred parts are no problem, I like charred parts!