An historical document, from an old Union hardware catalog. This is before the power line frequency was standardized at 60 Hz. across the whole U.S. I originally posted this to my watsonseblog.
Electronics & Stuff, a lot about LEDs
An historical document, from an old Union hardware catalog. This is before the power line frequency was standardized at 60 Hz. across the whole U.S. I originally posted this to my watsonseblog.