The stupidity of slimulations

Not sure, but I think almost ALL do. Oh, did you mean "useful" permeability? And therein lies the key.

Also, coercivity eats your high frequency performance alive. That 'delay' can make the permeability appear VERY low. But the origin is excessive coercivity and NOT permeability/frequency limitation. Just looks like 'permeability' is rolling off as a function of frequency when what is really happening is that 'useful' permeability is rolling off as a function of frequency. I hope that gives an inkling of what I'm trying to point out. Microscopic characteristic versus macroscopic characteristic, where the term, permeability for example, is broadly used leading to EXTRAPOLATION misconceptions. For example, keeping both coercivity AND permeability to describe the magnetic material leads one to understand where the true limitations come from, and therefore enable you to attack their origins and make improved products. For example, concentrating on lowering coercivity yielded amorphous materials. Sadly, their conductivity then causes eddy currents to appear which lower 'useful' permeability. So it goes.

Do you have an application in mind, other than something like HD drive heads, to operate at those frequencies?

Haven't seen many of the following types of tests, maybe only the spooks use them, but I vaguely remember at one time industry started slipping into using some weird exams, asking questions like, What tree would you like to be? I mean REALLY obtuse questions that are judiciously placed in a sequence to lead/direct the mind. Then the results of those weird tests are correlated to 'success' in others. Voila! you have a very effective 'objective' test predicting performance [and psychological profile] in potential applicants. Tests were even capable of predicting types of failure mechanisms/betrayal, etc.

Not sure, but also vaguely remember these tests were 'outlawed' for general use in industry. Anybody out there remember/know more about this approach?

Well, assuming R=R then I'd say Vout=Vdd/2 and that TC is close to zero. But I am probably wrong. What other answers do you get?

Not sure I could commute to AZ anyhow ...

piglet

I wish I were. I'm short and fairly innocuous looking. It works in my business; I can make a low-key initial impression until I figure out a situation, and then modify as needed.

There is reason why med schools employ the "see one, do one, teach one" strategy of education. "See one" just doesn't cut it.

But the college campuses are real pretty and a lot of lefty professors have cushy jobs and nice homes.

Hmm, and here I thought Vdc was the opposite of Vac. ;-)

We still use B+ for the raw battery voltage.

IME, the two are pretty much interchangeable. I suppose a Co-op would be a more formal program but both terms were used.

Even a bad model beats nothing. And inside of every bad model is a good model trying to get out. All it needs is a little help from a model maker.

I have an old board in need of repair. It has a basic schematic and a "big picture" description of its function. No other documentation exists to help me repair the board. No voltage levels, no waveforms, no nothing.

Despite its flaws, LTSpice enables me to get at least a rough idea as to voltage levels and waveforms. I also tune the models along the way so as to end up with better models.

I'm not that fortunate. :-/

I will be releasing models for OTS chips from time to time, and am open to suggestions as to what you'd like modeled. No hairy stuff, I'm busy with a paying hairy model already ;-) ...Jim Thompson

That's the right answer, but could I see your work ?:-} ...Jim Thompson

Hanging a door is a pita. I had to do it wrong (twice) before learning how to do it right. I guess the same can be said for various circuits...

George H.

Ha ha. If I showed you my work I'd be revealing proprietary information covered by NDA and I'd have to kill you !}

piglet

And campuses are 60/40 female to male!

But a lot of those "professors" are poorly paid assistants, without tenure or benefits. More $$ for the institutions.

OK, I see. No revelation then. Too bad.

I make and use lots of wideband transformers. The trick of extending the high frequency performance of a transformer consists, to a large extent, in keeping the flux out of the ferrite.

Jeroen Belleman

That's an interesting way to put it.

All the wideband transformers I've ever made have been transmission line transformers. Most of the high frequency current through them flows between the two sides of the transmission line and never gets out to influence the ferrite.

Do it! Do it!