Tunnel Diodes - They look awesome

Discussion in 'General Electronics Chat' started by Robin Mitchell, Sep 18, 2018.

  1. Robin Mitchell

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  2. ebp

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    They may still be in production in Russia (I've seen them for sale from ebay vendors in Ukraine, but I haven't look for a few years), but otherwise they are no longer being made. They were also useful for producing very fast pulses in test instruments such as time domain reflectometers.
     
  3. nsaspook

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    Aug 27, 2009
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    You can see the same negative resistance effect with a
    [​IMG]
    [​IMG]

    https://en.wikipedia.org/wiki/Pearson–Anson_effect
     
  4. rsjsouza

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    There is one manufacturer in the US: SSDI 1N4394/1N4395
    Macom used to have them, but all I see now are discontinued parts.
     
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  5. MrChips

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    Tunnel diodes are used in nuclear instrumentation electronics as fast analog comparator circuits.
    They are also found in Tektronix 422 oscilloscopes.
     
  6. AlbertHall

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    Also were used in the trigger pulse generator in oscilloscopes.
     
  7. ebp

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    I get the impression that SSDI will make you a batch to order. I can't imagine them being cheap.
    It looks like there are lots of eBay vendors still selling TDs from the USSR.

    Tunnel diodes were making the rounds among hobbyists in the 1970s as I recall. I think there might even have been one in the Motorola HEP series.
     
  8. rsjsouza

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    Yes, that seems to be the case as I couldn't find any distributor that sells these.
     
  9. bertus

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    Hello,

    Here I got some PDF about the tunnel diode and the lambda diode.

    Bertus
     
  10. Bordodynov

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    You can play with LTspice and the models of tunnel diodes that are in my collection of models.
    Here are two examples:
    Tunnel2.png Test3.png
    link:
    http://bordodynov.ltwiki.org
     
  11. RichardO

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    May 4, 2013
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    For what it is worth...
    Years ago I wanted a fast pulse to test the bandwidth of my used o'scope -- a Tektronix 475A. I was disappointed with the speed of a tunnel diode. I had much better results using a 2N2369 as an avalanche transistor.
     
  12. AlbertHall

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    I used to work on TDRs and they used an avalanche transistor circuit which, if memory serves, was also based on the '2369.
     
  13. RichardO

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    An the famous Jim Williams used the 2N2369 in his avalanche circuit to test op-amp slew rates.

    It was pure luck that I chose the 2n2369 for my avalanche circuit. It was years later that I saw the Jim Williams app note. As I say it: If I have a choice between good and lucky, I will settle for lucky".
     
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  14. danadak

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  15. OBW0549

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    Ahhh... tunnel diodes. These are ancient, not new: my GE Transistor Manual, 7th Edition (1964) has about 25 pages of tunnel diode circuits.

    Good stuff-- for nostalgia, anyway.
     
  16. danadak

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    Unijunctions, PUTs, we so need them as well.....:)

    Regards, Dana
     
  17. OBW0549

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    And don't forget Silicon Controlled Switches. And Snap Diodes, too!
     
  18. Bordodynov

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    By the way, in my collection there is a model for this transistor working in an avalanche mode and if you take information on my link, then in the folder Example There are several tests of the operation of transistors in the mode of relaxation oscillations in direct (avalanche) and reverse mode. There are also circuits designed to test oscilloscopes.
     
  19. bertus

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  20. Robin Mitchell

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    Thanks for the massive let down guys! Looks like I will have to try and forget about them now :D
     
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