John Larkin's LC oscillator
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From: Robert Baer on 11 Jun 2010 13:38 BlindBaby wrote: > On Fri, 11 Jun 2010 09:14:34 -0700, John Larkin > <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: > >> On Fri, 11 Jun 2010 09:09:29 -0700, BlindBaby >> <BlindMelonChitlin(a)wellnevergetthatonethealbumcover.org> wrote: >> >>> On Fri, 11 Jun 2010 08:37:43 -0700, John Larkin >>> <jjlarkin(a)highNOTlandTHIStechnologyPART.com> wrote: >>> >>>> On Fri, 11 Jun 2010 17:15:50 +0200, Jeroen Belleman >>>> <jeroen(a)nospam.please> wrote: >>>> >>>>> John Larkin wrote: >>>>>> I like the way it works with a very high turns ratio, very small AC >>>>>> drive at the emitter. But at lower ratios, it gets very nonlinear and >>>>>> becomes, if that means anything, a tuned blocking oscillator. The base >>>>>> capacitor value would be lowered so that the cap recharges a bunch >>>>>> during a oscillatory cycle. >>>>>> >>>>>> I'm sure JT and JF will spend the next week diligently searching for a >>>>>> set of values that will make my circuit not work. Then they'll crow, >>>>>> or rather, cluck about it. That's OK: as Woody Allen says, we need the >>>>>> eggs. >>>>> I made it squeg. Maybe that will please them. >>>>> >>>>> Jeroen Belleman >>>> >>>> Sloman is our resident squegging expert. >>>> >>>> John >>> >>> We should take a poll as to what attribute you are an expert in. >>> >>> I don't think it would result in the same determination that you >>> obviously think it would. >> Do you know what squegging means? Tell us. > > I have characterized a lot of oscillator circuits at the bench, John. > Remember... power supplies... That was years ago. Now it is what the > power supplies power. Still lots of oscillators though. > >> There are maybe two usages, both electronic, > > I have very little faith in your word derivative/origin declarations, > John. That is aside from the fact that I am familiar with the word. > Remember? I work in this industry. > >> but one of them is >> obscure, > > Perhaps only in your thinking. > >> and the other is even more obscure. > > Certainly only in your thinking. Well, now, if both usages are NOT obscure (and i know of only one and have been a tech for at least 50 years),please TELL US the source / creation of the word and the context in each case. That way we will know that you are not just doing a fantasy trip.
From: Robert Baer on 11 Jun 2010 13:41 YD wrote: > Late at night, by candle light, Jeroen Belleman <jeroen(a)nospam.please> > penned this immortal opus: > >> John Larkin wrote: >>> I like the way it works with a very high turns ratio, very small AC >>> drive at the emitter. But at lower ratios, it gets very nonlinear and >>> becomes, if that means anything, a tuned blocking oscillator. The base >>> capacitor value would be lowered so that the cap recharges a bunch >>> during a oscillatory cycle. >>> >>> I'm sure JT and JF will spend the next week diligently searching for a >>> set of values that will make my circuit not work. Then they'll crow, >>> or rather, cluck about it. That's OK: as Woody Allen says, we need the >>> eggs. >> I made it squeg. Maybe that will please them. >> > > Yes, the tank's Q must be kept high. Increasing La's series R makes it > squegg in a rather amusing way. Might be fun capturing it to a .wav. > > JL: Can you recall ballpark the values of the inductors and associated > frequencies in the physical circuit? High valued Ls tend to be rather > resistive unless they're grossly oversized. > > - YD. > In fact, it would be interesting to know how to "resonate" an inductor that has a lot of (internal) resistance. ..with resistance so high that it is almost impossible to see an LC peak at all.
From: Robert Baer on 11 Jun 2010 14:04 Jon Kirwan wrote: > On Thu, 10 Jun 2010 19:26:20 -0700 (PDT), George Herold > <gherold(a)teachspin.com> wrote: > >> <snip of what I wrote> > >> Hi Jon, I hope you�re not offended if I say that the first time I >> read this I thought it sounded crazy. > > Not at all. Cripes, can you imagine what would have happened > if Rutherford had gotten all offended when meeting with his > young students who might have proposed some idea? I had > loved reading, somewhere, that he would listen to any and all > if they thought they had _any_ idea, no matter how modest or > odd it may have been. They would take a break every > afternoon for tea, cake and buttered bread and just sit on > stools talking. Nice. 11 of his students went on to receive > Nobel Prizes, not to mention some of the collatborators who > also attended and also won Nobels. Not that I think what I > wrote is anything much. I'm just saying... > >> I took vol. 2 of �The Feynman Lectures of Physics� down to the creek >> when I got home this evening. In chapter 36 he does ferromagnetism. >> (do you have a copy?) > > I do have a copy and have carefully read the first 5 or 6 > chapters of the first book, only. I have not read chapter > 36. > >> He does an electro-magnet near the end. >> (36-5). Early in the chapter he says that if you are willing to >> accept the fiction of magnetic monopoles, you can think of >> ferromagnetism as the magnetic analog of the polarization of >> dielectrics. > > I'll read it, tonight. Though I may need to _also_ go back > and read on polarization to refresh that, as well. > >> And so I totally accept your picture� though I understand it >> differently. Thanks! > > It's the way I imagine it and it works to solve any questions > I've had about the concepts others teach differently (and to > me with less clarity.) I am sure, someday, there will be > some behavior that requires me to modify it. But so far for > my limited experience, it works well. I like it better > because I don't have to think about how recoverable EM energy > (which in my imagination can ONLY be stored in a vacuum) > might be one figure for vacuum, another figure for atom A, > another figure for aligned atom A, another figure for atom A > in an excited state, and so on. I just have to keep one > thing in mind... energy is stored in vacuum, only, and > permeability is simply a fudge factor used to estimate the > effective ratio of the vacuum path length and the vacuum path > length less the magnetic short circuit length (once alignable > atoms are aligned.) L_vacuum / (L_vacuum - L_shorted). It's > a fictitious parameterization so that we humans can use basic > measuring tools and simple observations plus that figure to > estimate the effective vaccum psth length remaining for > energy storage. But the recoverable energy really only goes > into vacuum, I believe. > >> Oh Feynman says the energy loss is the area enclosed by the B/H >> curve. > > Which makes complete sense. I mentioned before that I also > imagine aligning the atoms takes energy, but it isn't > recoverable. The work involved in aligning is largely ('all' > probably, unless there is a wound up spring recoil effect > which I don't at all imagine exists) converted to heat. If > you reverse the alignments, you do more work. And so on. But > you don't get it back. That goes into heat. > > It's only the energy stored in vacuum (energy cannot be > created or destroyed) where there is no possibility of "heat" > that you can recover. (Would be interesting to imagine the > case where you could actually lose energy as work converted > to heat in a vacuum... hmm... could you cause the vacuum to > heat up enough to create 'vacuum ash?' Enough letting my > imagination get away with me... ;) > > Jon It has been well over 45 years, so my memory is not too lear or complete concerning what is lossy and what is not (and why) regarding the magnetizing (or de-magnetizing) ferrites. Concepts remembered, not necessarily connected: magnetic domains, domain wall movement, polarization and alignment, crystalline structures, and maybe 2-5 other things forgotten. But it was clear (then) that some things are energy recoverable (i think that was polarization alignment) and some were not (i think that was domain wall movement). ...at least 2 of the many items from the dim past.
From: Robert Baer on 11 Jun 2010 14:07 Jon Kirwan wrote: > On Thu, 10 Jun 2010 23:20:32 -0700, I wrote: > >> The work involved in aligning is largely ('all' >> probably, unless there is a wound up spring recoil effect >> which I don't at all imagine exists) converted to heat. If >> you reverse the alignments, you do more work. > > I should add that the way I imagine re-aligning taking place > is with each atom as little aligned gyroscopes. When a force > is imposed on them to alter their orientation, they twist in > the field and this twist bumps them against others also being > turned and this results in some of the energy going into > lattice/material vibrations that amount to 'heat' in the end. > I'm not sure how to make that quantifiable, except that if > that imagination has any predictive value, it would suggest > that very fast changes would cause a great deal of heat as > the little gyros would twist quite strongly then. > > Jon Interesting...even if (and i mean IF) that mechanism was totally incorrect, it sounds like a very useful explanation that could be quantifiable and lead to useful results. First time i have heard of that.
From: Robert Baer on 11 Jun 2010 14:08
John Fields wrote: > On 10 Jun 2010 13:23:55 -0700, Winfield Hill > <Winfield_member(a)newsguy.com> wrote: > > >> In a ringing bell application, as the supply voltage sags, >> and the amplitude drops, I imagine the circuit will move >> from class C back to class A operation, before stopping. > > --- > Why imagine? > > Here's a circuit list that'll show it all _and_ it'll create a .wav > file, "bong.wav" in whatever folder the cicuit's in, so you can hear > it. > > Enjoy! :-) > Where? See nothing, am interested. Thanks. |