Discussion in 'General Electronics Chat' started by Rolland B. Heiss, Mar 5, 2015.

1. ### Rolland B. Heiss Thread Starter Member

Feb 4, 2015
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I believe there are only 1 or 2 companies in the States that make tunnel diodes anymore and this site explains how to make something quite similar at home quite easily. Figured someone here might find the link as interesting as I found it to be.

http://www.sparkbangbuzz.com/els/ntype-nr-el.htm

2. ### nsaspook AAC Fanatic!

Aug 27, 2009
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Negative resistance was once a very active field of research for high speed logic and RF technology (I built a UHF spy bug from one in the 70's), but as transistors became faster the technology was mainly a backwater part used in some older TEK scopes. Today that's possibly changing as some of the new quantum effect devices have bi-stable states that involve tunneling for negative differential resistance.

3. ### Rolland B. Heiss Thread Starter Member

Feb 4, 2015
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Interesting. You spoke of the new quantum effect devices that involve tunneling for negative differential. Are there new types of tunneling components and what do they look like? Have you any links to a photo or part number?

4. ### nsaspook AAC Fanatic!

Aug 27, 2009
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6. ### Motanache Member

Mar 2, 2015
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7. ### nsaspook AAC Fanatic!

Aug 27, 2009
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Try to think of the charge not as a hard particle like a marble but as a wave function with a probability curve of where (in a small volume of space) the momentum level and direction will be. So if we have a charge with a value 0.5 and a potential barrier with a value of 1.0 with a thickness on the scale of the probability curve. Classical mechanics would say it will never cross -> that barrier even if the charge value was 0.9 of the barrier in a static condition, it would just be reflected back <- .
Quantum Tunneling across the barrier is the effect of the exponential probability of some particles (as a wave function) at a lower energy than than the barrier crossing the potential barrier by going straight across that thin barrier instead of all or nothing over it.

http://hyperphysics.phy-astr.gsu.edu/hbase/quantum/barr.html

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8. ### Rolland B. Heiss Thread Starter Member

Feb 4, 2015
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Thanks for helping me understand it all better!

9. ### nsaspook AAC Fanatic!

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Last edited: Mar 7, 2015
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