The stupidity of slimulations

Mar 22, 2014 187 Replies

I didn't say it wasn't possible to model a switch-mode power supply. I said I'd like to see you correctly model one that is available from, say TI.

Of course, if *you* designed the regulator, you could model it. I

*highly* doubt you could model someone else's without have a clue what's inside or any of their models.

The real problem is that they paid *far* more and will probably spend the rest of their lives paying off their party.

One has to wonder what you do every morning.

I get to see the other end of my alimentary canal, briefly, when I clean my teeth.

Bill Sloman, Sydney

Please. NDAs don't cover the elementary stuff. Product plans, sure. Details, yet to have patents filed, sure. Yeah, that would be a big "FAIL" in my book, too.

I worked for one company, free, pretty much running their design review. The boss wanted to hire me but his boss didn't like my white hair. ;-) That's alright. My current boss hired me because of it. He doesn't like the kids schools are turning out these days, either.

For a decade, or more, where I worked in IBM, that was the only way to get hired. For the entire time I was in BTV, I don't remember any college hires who weren't interns. Most of them, five year interns.

Jamie's perceptions are limited by his cognitive defects. We were discussing job interviews, which are usually conducted verbally, face-to-face.

No readers involved. If Jamie can't keep that kind of detail in mind, his capacity to process complex sentences and keep track of their ramifications is obviously limited.

My involvement in political activity was limited, and nobody - least of all me - though that I had any talent for it. Jamie's perceptions here are are as reliable as we've come to expect.

Bill Sloman, sydney

o be satirical.

Jamie "lies" by inserting a "reader" into a job interview, and krw is too d im to notice.

Krw thinks that anything that he doesn't agree with is a lie, and since he' s too dim to process most of what's being said he consoles himself with the idea that everything that he can't follow is a mindless stream of lies tha t he doesn't need to understand.

A self-serving - if transparent - delusion.

Bill Sloman, Sydney

No, I believe that they had EE degrees. And I interview interns that I know have recently completed courses, or recently got their EE degrees.

It's just that a lot of people don't understand electronics, for good reasons. That would be a separate rant.

John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com

I used to have white hair. People treat you different when you don't.

John Larkin Highland Technology, Inc jlarkin att highlandtechnology dott com http://www.highlandtechnology.com

Not a subject that has ever come up in a job interview. And since Trotsky and Lenin were both agreed on the importance of "the leading roles of the - Communist - party" neither "-ism" has any merits worth discussing.

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Trotsky did go on to oppose Stalin, so he didn't get absolutely everything wrong.

Bill Sloman, Sydney

Yes he did. Trotsky advocated the violent overthrow of all non-soviet governments. Even Stalin resisted that and that was the 'reason' (other than Stalin's paranoia) for their split.

Stalin - bad Trotsky - worse

It varies with geometry and stuff. Consider this for example;

Fair-Rite 2743019447

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(Differential-Mode) Select Broadband Frequencies (43 & 44 materials) tab, click the part in the first row. Compare impedance to the permeability graph. (Gah, websites without direct links.)

Although this example seems to be pretty consistent: X and R cross at about 15MHz, and into cutoff, |mu_s| is only dropping by about 1/sqrt(F) so impedance will still be rising by about sqrt(F). Which means, say, 20 ohms at 10MHz should be 40 ohms (double) by 40MHz (quadruple); it's actually more like 50MHz, not terrifically far off. Seems reasonable enough that one my hypothesize some sort of skin depth or diffusion effect is at work. It doesn't continue past 100MHz though, and Z levels off.

Ok, might be a bad example. I've seen multilayer ferrite chips that specify strong peaking, which should have to do with internal capacitance and stuff. Which still doesn't really tell you about the material properties.

It's worth noting that, at least all Fair-Rite materials I think, are tested with the same geometry, which probably isn't the geometry you'll be using in a given application. And even though ferrite isn't very conductive, a MnZn core more than about four inches thick becomes relatively useless at useful frequencies (above 100kHz say), due to skin effect. (Not that this is done very often. I've seen MVA size ferrite cored transformers; they were built from 1x2x4" bricks glued together.)

Moral of the story, I guess: certain intrinsic material properties are probably inseparable (like bulk impedance in terms of the idealized equivalents of resistance, permeability and permittivity -- all of which apparently vary with frequency), and geometry tends to obfuscate things that much more.

Tim

Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com

Neither did the bloke who buried an ice pick in Trotsky's skull.

"Jim Thompson" wrote in message news: snipped-for-privacy@4ax.com...

Zero, obviously; you don't run BJTs from a VDD supply. VCC or nothing. ;-)

Tim

Seven Transistor Labs Electrical Engineering Consultation Website: http://seventransistorlabs.com

Sorry, I can't parse what you mean by these remarks. You're saying that a lot of people with genuine EE degrees, for good reasons, don't understand electronics??

Well you don't seem like the kind of chap who would be vain enough to dye his hair, so I'm guessing you went for a Yul Brynner?

So what do these people get paid as interns? If anything, I mean? Or do they just get travel expenses + lunch money? I'm just curious to know how much of a sacrifice some people are prepared to make to avoid the dreaded 'gap' in their CV...

Larkin is the most vain (pompous ass) person on this group. Are you kidding? ...Jim Thompson

-- | James E.Thompson | mens | | Analog Innovations | et | | Analog/Mixed-Signal ASIC's and Discrete Systems | manus | | San Tan Valley, AZ 85142 Skype: Contacts Only | | | Voice:(480)460-2350 Fax: Available upon request | Brass Rat | | E-mail Icon at

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| 1962 | I love to cook with wine. Sometimes I even put it in the food.

Yeah, my cow-orker is (cue ball) bald. He's "different". ;-)

How do you power BiFET circuits?

"Natty" means good/impressive in my dialect.

Coupling is all about flux paths that run through one coil but don't thread the other. The two coils formed by the two halves of a single-layer bifilar winding will have remarkably similar flux paths.

A multi-layer coil wound on top of that single-layer bifilar winding is physically further away and will presumably will have more unshared flux paths.

Bill Sloman, Sydney

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