[Milsurplus] "Antique" Silicon (?) Diodes

[Bruce Gentry]

 These are likely to be copper oxide instrumentation rectifiers, 
selenium was also used but not as often.  Their forward drop goes up 
with current, silicon and germanium are almost  independent of 
current.   Copper oxide diodes start to conduct around.2 volts at low 
current, and  have a small but measurable reverse leakage.  

    Bruce Gentry

David Stinson wrote:
> Is there anyone amongst us who seriously collects 
> early semiconductors?  I have some epoxy-encased
> diodes that appear to be early silicon.  Photos at:
>
> http://home.netcom.com/~arc5/olddiodes.JPG
>
> If anyone has any details on these, it would be interesting.
> These are obviously collectables, not to be used in service.
> But I tested representative batches anyway.
> The large green ones, marked "1YR1" and with a red dot
> at the cathode end, are about 80% good
> when tested with a 30 volt source and a 28 volt pilot lamp 
> load.  Forward drop is about 1 volt, which suggest silicon I think.
>
> The gray ones are unmarked except for a red dot at the cathode end
> and come in two sizes, "small" and "large(er)".
> ALL of them test hi-Z.  About half are open.  The rest still act like
> diodes, but with large forward voltage drops- like 15 volts.
>
> I have four lots, each of which contains ten of the large "1YR1"
> diodes, about 50 of the small gray and 8 of the large gray.
>
> Any collector can have them for shipping.
> I'm guessing $4 will ship them anywhere in the U.S.
> Overseas shipping at cost, with "first call"
> to our excellent members in Australia.  
>
> 73 Dave AB5S
>
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