|Rectifier marketing brochure.|
This is a great example of marketing. Basically, selenium rectifiers are really not that good. But, they were better than the alternative vacuum tube technology, so a company that made them got the idea that people could go around replacing burned out rectifier tubes with selenium rectifiers. This brochure is full of detailed technical information about how to do this for particular kinds of tubes, certain brands of radios, etc. It even includes a price list, which indicates that these things cost about a dollar, which was of course worth a lot more then than it is now. A modern silicon rectifier that works far better can be had for a few pennies: As part of an integrated circuit the price of an individual rectifier would be essentially zero.
Source: eBay seller nrankscs
Contributor: Theodore Gray
Acquired: 3 January, 2004