XPost: sci.electronics, sci.electronics.basics, sci.electronics.design   
   From: don@manx.misty.com   
      
   In article , JosephKK wrote:   
   >On Tue, 22 Apr 2008 13:42:10 -0700, John Larkin   
   > wrote:   
   >   
   >>On Tue, 22 Apr 2008 20:19:49 GMT, Rich Grise  wrote:   
   >>   
   >>>On Sat, 12 Apr 2008 17:51:10 +0200, ronwer wrote:   
   >>>>   
   >>>> I am doing a study into the early use of silicon diodes in radar and   
   >>>> communication equipment during the Second World War.   
   >>>   
   >>>Did they even _have_ silicon diodes in WWII? I remember when they   
   >>>announced the first transistor, some time in the early 1950's.   
   >>>   
   >>>Thanks,   
   >>>Rich   
   >>   
   >>Yup. Most of the WWII radar diodes were silicon point-contact types,   
   >>Schottky diodes actually. The best 1943-vintage mixer parts were about   
   >>as good as any packaged schottky you can buy today... 0.2 Vf, 0.2 pF,   
   >>decent noise figures to 30 GHz.   
   >>   
   >>The point-contact transistor was invented at Bell Labs in 1947. Most   
   >>of the relevant semiconductor theory - bandgaps, hole/electron   
   >>conduction, doping - was well understood by about 1940. The RadLab   
   >>guys didn't develop a PN-junction diode or the transistor because   
   >>their mandate was to develop radar to win the war.   
   >>   
   >>John   
   >   
   >Gee, John.  Where do you get schottky diodes with V(f) below 0.2 V at   
   >I(f) of 1 mA?   All the ones i could find were over 0.33 V and mostly   
   >0.4 to 0.5 V.   
      
     I am on a temporary setup now that does not have Acrobat, but I somewhat   
   remember Vishay-IR STPS1L30UPBF or 1N5818 dropping maybe .35 volt at 1   
   amp.  These are 30 volt 1 amp Schottky rectifiers.   
      
    - Don Klipstein (don@misty.com)   
      
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