XPost: sci.electronics, sci.electronics.basics, sci.electronics.design   
   From: jonk@infinitefactors.org   
      
   On Fri, 21 Aug 2009 10:30:09 +0100, "christofire"   
    wrote:   
      
   >   
   >"Jon Kirwan"  wrote in message   
   >news:bvhs85d9ajq1e0om8dmku8qq63mgbtm9n7@4ax.com...   
   >> On Thu, 20 Aug 2009 20:30:19 -0700, John Larkin   
   >>  wrote:   
   >>   
   >>>On Thu, 20 Aug 2009 22:07:46 -0500, "Martin H. Eastburn"   
   >>> wrote:   
   >>>   
   >>>>First, Si diodes were not used in WW II. The PN SI diode wasn't invented   
   >>>>yet.   
   >>>   
   >>>Nearly all the radar first mixer diodes were silicon point-contact   
   >>>types, essentially silicon schottky diodes.   
   >>>   
   >>>See the MIT Rad Lab book, volume 15, "Crystal Rectifiers" for a bunch   
   >>>of WWII (and pre-war) stuff about diode development. This is from that   
   >>>book:   
   >>>   
   >>>ftp://jjlarkin.lmi.net/RadDiode2.JPG   
   >>>   
   >>>ftp://jjlarkin.lmi.net/RadLabDiodes.JPG   
   >>>   
   >>>>Selenium wafers and sticks were the power types   
   >>>>and point or whisker diodes for RF.  [ I have some of these in lead   
   >>>>cans ]   
   >>>>   
   >>>>In the 60's it was still that way.   
   >>>   
   >>>Funny, I recall using lots of silicon PN diodes (and SCRs, and   
   >>>transistors, and tunnel diodes) in the early 1960's. Tek was using   
   >>>GaAs diodes in their sampling scopes ca 1964.   
   >>>   
   >>>>Silicon diodes were developed by bell labs for internal telephone use   
   >>>>but semiconductor had to be invented first.   
   >>>   
   >>>No. See the RadLab book.   
   >>>   
   >>>>Look at the date of the transistor.  Silicon diode and Germanium diode.   
   >>>>   
   >>>>I know Radar in B52's were using Selenium and Germanium for RF.   
   >>>   
   >>>Selenium was never used in RF or radar, except maybe power supplies.   
   >>>Far too slow.   
   >>>   
   >>>John   
   >>   
   >> It was certainly used in the power supplies.  Not maybe.  I actually   
   >> owned a radar unit that was commissioned for navy service in 1944.   
   >> Nice selenium series stacks used as diodes in at least some of the   
   >> power supplies.  Also used vacuum tube VR150's for regulators.   
   >>   
   >> Jon   
   >   
   >VR150 is not a vacuum tube - it's gas filled (argon/neon), cold cathode.   
      
   Sorry.  My mistake.  Looked like one, and of course you are correct.   
      
   Jon   
      
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