Nyquist
Everyone interested in low noise design should read this. The clear reasoning is so refreshing and intuitive.
http://www.physik.uni-augsburg.de/theo1/hanggi/History/Nyquist.pdf
Everyone interested in low noise design should read this. The clear reasoning is so refreshing and intuitive.
http://www.physik.uni-augsburg.de/theo1/hanggi/History/Nyquist.pdf
As stated before, distortion is most likely pointing in the direction of core saturation; this can easily be checked with a voltage generator and a scope while monitoring frequency and amplitude.
From an engineering point of view I would like to know where the distortion comes from.
Correctly functioning transformers of this type exhibit almost non measurable distortion.
Since the grid is virtually nothing but crimped connections, I guess we should give up.
Another thing if your micro-volt level rectification is repeatable there are radio astronomers that would kill to have it.[/QUOTE
Real crimpers actually use enough force to get a cold weld! Amp used to do informational papers on this when they had to convince folks to give up soldering!
Micro-rectification...Grrr ain't no evidence, done the test, don't mix fairy tales with morality plays!
OK humor time, your electricians fingers probably don't cold weld unless he's the Hulk.
Scott, Scott, Scott,
Now that is really sinking to a new level. If you quote old ground breaking for the time papers, you will reveal the great secret of techno babble.
When an area of discovery is new you have to write clear concise and understandable papers, otherwise no one will understand your points. Only after the worthy understand it do you introduce shorthand jargon that make it difficult for the unwashed masses to join the worthy. The final step is to produce textbooks on the matter that require a paid surrogate (Faculty Member) to translate to the perspective initiates. At that level the original clear concise explanation is so well buried the secret is safe.
Shame on you for violating this rule.
During one college course I had a professor who was really not fluent in English, teaching what should have been a significant course from notes only. The first test had a high score of 14% right with an average of 6%. I cheated and bought a used textbook from way back when the text also had to educate the teacher. Still did not do too well, so what exactly is an Ohm?
ES
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Non-linear magnetization of the core which manifests itself across the primary DC winding resistance (which is why you can effectively eliminate it by driving it with a negative source impedance equal to the primary DC winding resistance).
se
That's where an electrical engineer would start, by identifying the source of the problem he is trying to solve. That's the first step towards actually solving it. What the hell would you want to do something like that for in a place like this?
This has more to do with hysteresis.
Driving amorphous core transformers (which have very little hysteresis compared with silicon steel transformers) with low source impedances like MC cartridges will have virtually no non-linear distortion of importance.
John's measurement at 10 Hz of the two step-up transformers with such different results is not a hysteresis matter but, once again, points in the direction of core saturation.
I am still curious after John's measurement set up, especially at which amplitude the 10 Hz measurement was done. John still there?
Yes, I am, and please forgive me, I could ONLY measure at the lowest input level that I could practically measure with my ST 1700B analyzer. This is a relatively HIGH level of input (to the test equipment), but it appears to TRACK with level. I don't have a SPECIFIC WORST CASE OUTPUT AT 1/2 Hz, but comparison between two almost identical transformers makes me concerned.
Of course we must keep the riff-raff out, as a professor at Tufts told me, that's why some engineers talk only about noise temperature. I approve of your use of the term initiates, it alludes to the Freemasons, etc.
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Ultraperm 80 is on sale for about 11 cents a square inch (w/shipping). I've got some on order but expect to use it flat. (Apparently, its lack of copper makes it less pliable.) It's 0.005" thick which is equivalent to about 0.05" (18 gauge) stainless steel. (Also, have 140 VAC varistors on order based on your article Ed.)
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What is hysteresis but a non-linear magnetization of the core?
Sure. But John's not comparing an amorphous core transformer to a steel core transformer.
Also, "amorphous" by itself doesn't really tell you anything. You can get amorphous in steel, nickel and cobalt.
What John's comparing is an amorphous cobalt core transformer to an 80% nickel laminated core transformer.
So you're saying the amorphous cobalt core is saturating sooner than the 80% nickel laminated core?
se
That's much better only $58.74 per pound. These days I pay $.45 for mild steel, which is considered high priced.
Good luck on you project.
Steve,
You know perfectly well it is not just a non-linear effect. The best explanation of hysteresis I heard is "you know when you wiggle a knob, you have to twist it a bit more in the opposite direction when you want to reverse it? That dead zone is hysteresis."
That remnant of magnetization that has to be reversed before the curve goes the other way can be expressed in theory with an infinite series. That gets into formal math and FORMAL meanings of terms.
ES
Raw material. Stamping is not a problem for 29 gauge or thicker. For thin stuff I have to stack it between a holding material that also gets punched.
Attached is a picture of one of my back room toys. (We use cardboard for testing the punch program!)
Attachments
Have an annealing furnace too?
Coolness!
I need some leather bits punched. Interested?
se
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