[Test-Equipment] Tunnel Diodes

[WBob]

1N3712 are available a lot. GE made them as late as 2002 according to:
http://www.icquote.com
WBob


Barry L. Ornitz wrote:
> Chris van Lint, <thai1@netvigator.com>, is looking for 
> replacement tunnel diodes for his Tek 284 pulse generator.
> 
> Sadly, tunnel [Esaki] diodes are almost "unobtainium" these 
> days.  Some of the microwave semiconductor manufacturers still 
> make back diodes, which are tunnel diodes that have been 
> optimized for reverse conduction, and used as sensitive 
> detectors.  These have not ben optimized for negative 
> resistance and will probably not work in this application.  
> Alpha Semiconductor was one of these manufacturers.
> 
> At one time Custom Components of Linden, NJ, was the only 
> manufacturer of replacement tunnel diodes in the USA.  They 
> essentially duplicated the General Electric line of tunnel 
> diodes such as the TD-2 and 1N3712.  I have heard recently 
> that they no longer supply gallium arsenide diodes.  
> Supposedly Metelics Corporation of Sunnyvale, CA, also 
> manufactures tunnel diodes.
> 
> The company I have heard most about lately is American 
> Microsemiconductor, Inc. who specialize in obsolete 
> semiconductor devices.  About two and a half years ago, I 
> received literature from them on a line of tunnel diodes they 
> were planning to produce.  Price was through the roof!
> 
> Other possibilities for you to try are Deane Kidd in 
> Beaverton, Oregon, a retired Tek employee who stocks many 
> replacement parts, and Stan Griffiths, who specializes in 
> older Tek oscilloscopes.  I do not have addresses handy for 
> either of these gentlemen, but I am sure others here can 
> provide these.  I know both of these fine individuals; they 
> are really extremely valuable assets for restorers of older 
> test equipment - and exceptionally helpful.
> 
> If the 21 mA Chris specified is the peak point current for the 
> diode, my guess as to type would be 1N3720, 1N3721, TD-5, or 
> TD-5A as these have peak point currenys of 22 mA.  Their case 
> size is similar to what Chris describes too.
> 
> I note Chris' email address lists NETVIGATOR.COM.  This seems 
> to be the only Internet provider in the Peoples Republic of 
> China that I do not get tons of SPAM from!  If you need to 
> email me directly, Chris, please include something in the 
> subject line about tunnel diodes or my filtering software will 
> reject the email as spam.
> 
>         Barry L. Ornitz, Ph.D.     WA4VZQ          ornitz@tricon.net
> 
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