How tunnel diode and Vericap diode work?

[nalaka]

please any one explain How tunnel diode and Vericap diode work?i noticed Tunnel diode in some diagrams.but i never notice a vericap diode.want to know how they work and a simple diagram that these diodes placed.

[SevenZero]

tunnel.png (1.94 KiB) Viewed 11510 times

A tunnel diode or Esaki diode is a type of semiconductor diode which is capable of very fast operation, well into the microwave frequency region, by using quantum mechanical effect called tunneling. Read more at Tunnel diode.

varicap.png (2.06 KiB) Viewed 11510 times

A varicap diode, varactor diode, variable capacitance diode, variable reactance diode or tuning diode is a type of diode which has a variable capacitance that is a function of the voltage impressed on its terminals. Read more at Varicap.

Note that varicap diodes are also knows as tuning diodes. Don't get confused that name with tunneling diodes which is with completely different operation.

[SemiconductorCat]

varicap diodes are used when we want a frequency is a function of voltage.
We use these in PLL (phrase lock look ) and VCO oscillators.

In the filed of the microwave engineering the applications are tremendous .it's better better better
to learn math and theory and applications , circuit configurations on it.

I'm not satisfied with the first answer , because there's no enough information on how it could be
used on a particular application.
This: http://www.electronics-radio.com/articl ... -diode.php
may give a basic circuit configuration of very basics of it's functional theory.

But beyond that you need to a signal analysis (AC) of the circuit. And that note also not explains it.

Since you,posted on monday, wait for today, I think a answer from Neo like will be enough with information.
Otherwise ask in electronics.stackexchange.com .

For your question , simple example,


source ; http://www.electronics-radio.com/articl ... -diode.php

[nalaka]

thank you very much bro.i admire both of you.please stop combat each other in EC.

[SevenZero]

please stop combat each other in EC.

He he.. I have no fight with a student like Semi... I'm in the field for more than 12 years now and Semi.. hasn't even yet started a job. He has a long way to go. I only fight with people of my age and capacity.

For Semi.. I try my best to give him advises, trying to change the way he thinks, etc... for the betterment of his future. No doubt he is a fantastic enthusiast. Only thing is his attitude must be changed to get him in to industry.

[SemiconductorCat]

Combat ! [ Combat to take as much knowledge as you could, these are simple engineering applicaions
we need to use these things and earn money, that's the real combat ].

I didn't knew anything about the tunneling diode when I post already. Then I went to the library,
internet and have wasted around 4hrs completely dedicated to the tunneling.So these are my
path footsteps that I have went, suggest you to follow my footsteps if you like to learn this all
in 1/2hrs like time.

Start read from here --V-[continues the uncompleted part of my note.
So that part continues here.]

Before we use tunnel diode we need enough understand of it's theoretical background.So that background
continues down here.

1. Theoretical Background.
The tunnel diode is based on the principle of tunneling. But tunneling is based on the
Heisenberg uncertainty principle, Simply,
if you know all the kinetic information about a particle at a known time , you only can give a probability about it's
kinetic information a t+ small_time.

For a example you can't take a map of a atom and said that electron will be there at a particular known
time. Only you could give a probability map.You could only say the probability of the electron at a given time.

So based on that what's tunneling. Suppose you hitting a wall with a ball , but ball does not have enough
kinetic energy to break the wall and pass through it, but there is a less probability that ball can pass through
the wall and exist on the other side. See this video -V

[media]http://www.youtube.com/watch?v=cTodS8hkSDg[/media]

So now you know what's tunneling , now you are ready to watch this video.
This video explains the function of a tunneling diode using the tunneling, and this video does not
explain the tunneling.

[media]http://www.youtube.com/watch?v=Fuy1ow7LQ94[/media]

Now,you know how it work. now the fun part comes in. Applications [Since I'm BTech Student].


Applications

There are many applications in tunneling, But here I'm going to mention the applications related to
electronics.
1. Computer EEPROM/EPROM/PROM memories.
2.TFET ( Tunneling Filed Effect transistor) and Quantum transistor.
3. Switches and sequential logic, combination logic,hi-speed SRAM. (some are excremental).
4. CCD Cameras and high precision sensors.
5. Tunnel Diode.

and also have a disadvantage in VLSI frabrication which leads to increase the current leakage.
and many more applications outside electronics.

Applications Inside Electronics and Inside Tunnel Diode.

1. Oscillators.


More stable Xtal oscillator configuration are exists.
But I didn't find that configuration on internet. You better find that book and refer it. It's worth reading it.

And the above method is just a relaxation oscillator.
Where the negative trans conductance let us to make that.

2. High Speed Switching.
3. Combinational Logic circuits [Gates] -high speed.
4. Sequential Logic and memory.

[2][3][4]The circuit configuration exists on that book ,I searched on internet but unable to find it for ya.


Now we have introductory level knowledge about it. Now it's time to run into the math and signal analysis.
I'm not yet skilled enough to do that. So I'll leave the discussion to SevenZero or Neo to continue from
here.

Hope you enjoyed your 1/2 hrs.
--Thanks Reading This--

[SemiconductorCat]

Only thing is his attitude must be changed to get him in to industry.

LOL ! So you won't going to employee me even I have the qualifications ? [ I don't have enough currently].
So even if I experienced and qualified don't you add me to your company ? Don't mind me telling this.It
completely sounds LOL to me.

BTW, to complete this discussion , could you do the signal analysis part of applications? Since I
already completed the introductory part. I think introduction is enough now.

In Varicap,
1. something like analysis of a hartly oscillator.

In Tunnel diode.
2. Something like relaxation oscillator.

Or invite the neo for this?

[SevenZero]

LOL ! So you won't going to employee me even I have the qualifications ? [ I don't have enough currently].
So even if I experienced and qualified don't you add me to your company ? Don't mind me telling this.It
completely sounds LOL to me.

I met quite a lot of intelligent people throughout the world including two lead design engineers in Intel (both husband and wife... they made a temple in Sri Lanka recently too) and a top engineering manager in Microsoft. So I have seen and being in the community of intelligent people for so long now. I like to live with these people who are highly intelligent regardless of their qualifications. Neo is also one of them who has an unbelievable intelligence & capacity. Saman is another. In Buddhism, when people become intelligent, they become very calm, quite, very listening, down to earth, etc... I experienced this within my community. Most intelligent people I have seen are the most simplest. If you talk to one of them in a meeting or something, you might not even notice how intelligent he/she is because they don't have that boosting, show-off type characteristics.

If someone wants to join with that community, in your words, it's not a magic (I don't want to talk about a commercial venture such as company. Before all friends, community, etc.. matters). If you can develop those characteristics you can be there or else you can be the king of your own world

[SemiconductorCat]

If someone wants to join with that community, in your words, it's not a magic (I don't want to talk about a commercial venture such as company. Before all friends, community, etc.. matters).

Yep right ! joining your community is quite interesting for me. Not to become intelligent( I hve given this along time
ago) , but it's very easy to live with your community and I need some community to live either.Even it takes money
it's very very easy to get a item from the nice guy's shop. Sounds like you only have experience with nice guys.
So employ only nice guys [like me ].

But anyway I couldn't stop talk about the commercial interest, but I could stop talk it in here [expert core] since
this is a org site, and as I respect you.

But we are not talking about any commercial applications here. They may be indirectly commercial, but our point
is 'Engineering Applications'. When I talk Engineering applications I only concentrate about Engineering, When I think
commercial [that's my way of life], it's commercial. So I think we could live together in a one community.Long
live ECore.

So shall we complete the discussion. To complete the discussion and push it forward we need those two analysis.
These are on that book and book with me. Unfortunately I could get it enough till. It still little bit complicated
and messy for me. So that's why I invited you to it.

However sounds like you don't have some time to complete it. So I'll going to complete it in next week.The actual
problem is not whether it's a commercial or pure Engineering application[who cares? do you ask "For what?" when
you selling a knife?"]. The problem here is when I write that part ,it will lead to mistakes. So it's better you write it.

[SevenZero]

Okay, I'll answer directly.

So you won't going to employee me even I have the qualifications ?

I don't mind what qualifications you have. I believe you have the ability to quickly read something and understand the required points and go on. Only thing is you need to change your attitude. First learn to listen to others. Secondly learn to tolerate ideas of others. Thirdly when you learn more (so your head becomes heavy) learn to be more down to earth. Don't ever think that you are the best, that you know everything, you are an expert, non other is better than you, etc... Those mentalities make people look like fools even though they get a short term reputation. When you practice those, I will guarantee that you will feel an internal development of yourself. You will feel you are changing from within you.

So even if I experienced and qualified don't you add me to your company ?

If you are qualified and experienced, chances become high on entering a good company. What matter me the most is the attitude. I have seen lot of talented people but when they are not having the right attitude, I found they live a unsuccessful life. So my advise to you is to change your attitude towards the world, start loving everybody irrespective of their material standard such as knowledge level, experience, wealth, etc... and just be a gentleman. I want people to call me a good man rather than an intelligent man. Because that's what I'll take to my next life.