Talk:Avalanche transistor

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This article is all nice and so, but before diving into math maybe a typical circuit could be displayed? And maybe you could mention how well the transistor and the avalanche go together. In common emitter as I switch emitter-base into conduction at the same time the voltage base-collector is reduced and avalanche quenched. In common base usually the current is reduced, but it seems doing avalanche means soaking large amounts of current through the base? What is the difference to the diode, being able to sustain the discharge to lower voltages at the end of the pulse? Is there anything similar like the plasma formation in the breakdown of gases? Are avalanches in semiconductors always in the Townsend range? I am sure the solution are in the formulas, but I almost feel like doing original research when tying to extract it. Arnero 13:21, 9 February 2007 (UTC)Reply

Hello, and first of all thank you for your appreciation of the article. Now let's try to answer questions: the absence of pictures (not only of standard application circuits, but also of various voltage-current characteristics and so on) is due to the fact that at present I have not a free software tool of the necessary capability to produce good circuit pictures and good simulations. I am trying circuit macros for LaTeX and qucs, but there is a lot to work to do, so I am proceeding slowly. You're right when you say that the joint behavior of transistor and avalanche multiplication effect lacks an adequate description: I will try to improve this point in the future. However, note that a cause of this is that I have not expanded sections on triggering i.e. external control of avalanche transistor circuits, since, as told before, at present I am not able to produce pictures of electronic circuits of adequate quality. As you guessed there are two ways to trigger an avalanche transistor: base triggering as is usual in common emitter circuits, and collector triggering, which is far from usual. Their accurate description needs a description of the basic avalanche transistor circuit that still lacks for the above reasons. About the differences between avalanche transistor and avalanche diode, the main difference is the presence of the transistor effect jointly with the avalanche multiplication on the

I_{CBO}

current, which gives the device a negative differential resistance characteristic, and thus the ability to switch between two stable states: this should be explained by a several pictures together with formulas.... About the question on plasma breakdown behavior in semiconductor devices the answer is yes, but it is not a phenomena proper of avalanche transistors: If you want to find something like plasma discharge in semiconductor devices, you have to look at IMPATT or TRAPATT diodes. In a plasma-like discharge

M

is greater than

1

i.e. every electron impact generates more than one another electron, so one loses the control of the discharge: in cited diodes, this doesn't matter, while in a transistor it matters a lot. This answer also to your question about Townsend-like discharge in semiconductor devices: devices using breakdown multiplication, notably avalanche photodiodes and avalanche transistors, give an output current which is strictly under control of an input stimulus, so their multiplication coefficient has to be less than infinity. Last, about the feeling of doing original research that you have when you read the formulas in the voice, I can assure you that it is the same for me: I got interested in transistors working in avalanche region two years ago (2004) but I have still to found a complete reference giving a fairly accurate theoretical study, as well as some details on application (one solution could be D'yakonov's book, but until now I have found only excerpts of it). This was one of the reasons for which I decided to edit this wiki voice: and also this is one of the reasons it is a bit "stubby", but I am still working on it, as my plan of the voice, shown below testifies. :) Daniele.tampieri 19:10, 17 February 2007 (UTC)Reply

A proposal for the plan of the voice

Latest comment: 17 years ago2 comments2 people in discussion

It may seem a bit later to detail a plan when several of its part are already developed: however, since there are still several parts to be augmented and refined (also with the inclusion of several images) I have decided to release it to a wide public, just to give the feel of my intentions.

Basic Theory

Static Avalanche region characteristics
Differential dynamical model

Second breakdown region: only glimpses since the theory is even more difficult.
Applications

Avalanche mode switching: basic circuits, triggering and so on.
Avalanche mode amplification: the Controlled Avalanche Transit-Time Triode (CATT).

"See also" section for internal links.
"References" section: what has been used for the redaction of the voice.
"Bibliography" section: where to look for a deeper understanding of shown topics or where to found topics not touched.
"External links" section

Theory: www pages dealing with various aspects of the theory
Applications: www pages dealing with applications.
Varia: homepages of contributors, links detailing the history of the subject, bazaar :).

I hope this gives better overview on what I'm trying to do. :) Daniele.tampieri 19:47, 17 February 2007 (UTC)Reply

OK, then I will probably just sit still and wait. I use inkscape for wiki, because of its SVG output. I already did one simple circuit. I tried TinyCAD. I use LaTeX only if I have to. My interest in avalanche comes from the regular discussions why our nitrogen laser does not work so great.Arnero 08:42, 18 February 2007 (UTC)Reply

Harvrefcol -> Citation

Latest comment: 13 years ago3 comments2 people in discussion

This article uses a very unusual citation templates, {{harvrefcol}}, which produces an output which is (usually) identical to {{Citation}}. (The only difference is the way that the journal volume, issue and number appear).

{{Harvrefcol}} appears in only five articles. Obscure templates such as {{harvrefcol}} tend to be poorly maintained and often have incomplete functionality. {{Citation}}, on the other hand is used in more than 56,000 articles, and is uses the same core as the {{cite *}} family of templates, which are used several million articles. This family of templates is very well maintained and well documented.

Any objections to converting {{harvrefcol}} to {{citation}}? ---- CharlesGillingham (talk) 19:10, 20 December 2010 (UTC)Reply

I have made this change. It is easy to reverse if anyone doesn't like it. ---- CharlesGillingham (talk) 07:41, 24 December 2010 (UTC)Reply

Thank you. I would have done the migration from the {{harvrefcol}} to the {{citation}} template long ago, if I were a bit less lazy. :D Daniele.tampieri (talk) 16:53, 6 April 2011 (UTC)Reply

External links modified

Latest comment: 8 years ago1 comment1 person in discussion

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Static avalanche region characteristics

Latest comment: 2 years ago1 comment1 person in discussion

In the formulas mentioned one of the constants is a bit mysterious: "n is a constant depending on the semiconductor used for the construction of the transistor and doping profile of the collector-base junction" So it varies from transistor to transistor I assume and that is why there is no value given, but perhaps it's possible to give a typical figure/range for "n" or values from a common example transistor? RulesForThee (talk) 14:01, 15 June 2022 (UTC)Reply

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