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Comments on How to plot the I-V curve of a tunnel diode?

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How to plot the I-V curve of a tunnel diode?

+3
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I am trying to understand tunnel diodes by experimenting with them. Research tells me they can have negative resistance, and can be used to build a high frequency oscillator. Tunnel diodes are supposed to have this I/V characteristic:

Image

I don't really understand negative resistance, so I thought plotting the I-V characteristics myself would help me understand. Unfortunately, that didn't work.

What I did:

  • Connect PSU in series with a protective, current limiting resistor, and the tunnel diode.
  • Increase/decrease voltage level, in steps as fine as mV, and measure corresponding current values, as fine as 100 µA.
  • Record each point on a graph of current as a function of voltage.

Here is my test setup:

Test setup

As I increase voltage from 0 to IpeakV, the current increases as expected. Once approaching the IpeakV, the current suddenly jumped from tens of µA to some 400/500 mA. In other words, I just missed the most important measurements, those of the negative resistance region.

Why can I not measure the current as soon as the gradually increasing voltage V enters the negative region? How can I tell the tunnel diode not to "skip" the tunnel?

semiconductor-diode tunnel-diode component-characterization
posted almost 4 years ago
1y ago by Lorenzo Donati‭
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tlfong01‭
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General comments (3 comments)
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How to test a Tunnel diode in 25 words or less.

With DC bias = ~490mV with fine tuning and a small signal swing of 60mV you can generate a IV negative slope of -16 Ohms.

Image of Tunnel diode test

posted almost 4 years ago
4y ago
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TonyStewart‭
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General comments (4 comments)
General comments

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Circuit fantasist‭ wrote almost 4 years ago
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Attractive experiment... If the load line could be shown...

tlfong01‭ wrote almost 4 years ago
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@TonyStewart, Many thanks for you answer, which inspires me to learn more things. I have never heard of Falstad Simulator. So I will google and wiki. And as I mentioned in the beginning sections of my question, I confessed that I don't clearly know what actually is a load line. I never designed a load line. I only read that for tunnel diode, you can have 3 load lines, one for monostable, one for bistable, one for astable. So perhaps I should design and "implement" them on my little bread board.

tlfong01‭ wrote almost 4 years ago
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I randomly browsed your other answers for more interesting new ideas. One thing that caught my eyes is your answer about using MOSFET as a voltage follower, to replace op amps. I am now thinking of using an op amp in my tunnel diode testing circuit, but I have very little experience and I only know that op amp circuit is difficult. So using mosfet to replace op amp is too good to be true.

Skipping 4 deleted comments.

Olin Lathrop‭ wrote almost 4 years ago · edited almost 4 years ago
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Inappropriate comments deleted. Comments are not for content, and certainly not for chatting between two users who didn't even write the answer the comments are under. Knock it off already! If you want to explain to someone what a "load line" is, or anything else for that matter, put that in your own answer. This space is reserved for feedback to Tony on his answer, nothing else.