In December of 1906, Lee DeForest applied for the patent on the Audion, a three element tube. Fleming had already demonstrated the 2 element valve (diode) a few years earlier - after intense study of the 'Edison effect' of darkening lamp bulbs. Applications of the tube (such as for amplification and oscillator) didn't really become widely known until a few years later, and have been a source of patent contention (4 people claimed discoveries). I prefer to believe that Edwin Armstrong, the young ham, first understood the actual working of the vacuum tube enough to apply feedback and make an oscillator. I just finished reading a scholarly but small book on the interactions of Marconi, Fleming, and DeForest, "From Marconi's Black Box to the Audion", by Sungook Hong. It was published by MIT Press in 2001.
>From everything I have read, DeForest was quite the tinkerer, but he didn't >really understand that electrons, not ions, were the functioning mechanism in >his tubes. He also made a few missteps along the way in business with some >unscrupulous partners. It took others to improve his device (with better >vacuum) to really make tubes work well. And Marconi, well, he was hung up on >spark transmission, ignored the Poulsen/Federal arc (close to CW) and didn't >jump on HF alternators either (like GE did). Tubes became the equalizer >eventually, as they became the WAY to make, detect and amplify RF. Happy anniversary of the patent, though. John K5PRO ______________________________________________________________ AMRadio mailing list List Home: http://mailman.qth.net/mailman/listinfo/amradio Partner Website: http://www.amfone.net Help: http://mailman.qth.net/mmfaq.html Post: mailto:[email protected]
