Are hybrid parameters useful for design?

[Rajib Kumar Bandopadhyay]

Can I have the current picture in the developed countries on h-
parameters? I believe, with so much computing power at their hands,
people should not use h-parameters nowadays. They have no reason to. In
case of complex circuitry, you could do simulations, and in practice, you
use ICs in place of transistors. what is your experience with hybrid
parameters? Could you discuss this with people in the univ. laboratories?

I would mention an important aspect which intrigued me
while I was studying in Univ. The theory books put so much emphasis on
hybrid parameters, but to me, they are good for later analysis, i.e.,
not to invent something new, but when invented, they try to find how
the system work, not for learning electronics principles. And also, in the
practical world I did not come across specific cases of using
h-parameters. I thought - such wastage of time and effort!

 

[John S]

I've never used them and I don't know anyone who does. They are not on
transistor data sheets.

I must disagree with you, John. I know you have heard of hfe. And, I
still have numerous modern data sheets with such things as hre, etc.

John

 

[John S]

I got exposed to h-params in school, and in the old GE Transistor
Manual. But I don't use them... never did, actually. HFE is what we
call beta in our working transistor mental model. Some of the concepts
overlap. I suppose some of the disagreement is terminology. But the
h-params of a transistor are just linear approximations at one bias
point which, to me, represent a lot of work to get a non-general
approximation of transistor behavior.

So what, John?

Allow me to cut and paste your response above (maybe because you have
reading comprehension problems):

You say that they are not on transistor data sheets and you are wrong.
THAT was the essential reason for my reply; not all your other verbiage.

Do you use h-parameters to design transistor circuits?

No. So what? Are you just trying to pick an argument? Did you READ what
I wrote?

I recently Spiced a circuit that really depends on transistor Vbe
exponential behavior, and Cbe leakage, over temperature. H-params
aren't useful for nonlinear modeling.

All those partial differential equations are semi-useless. You don't
need them for simple circuit design, and they are useless for more
complex nonlinear stuff.

I don't give a s**t and SO WHAT?. LOOK AT WHAT I POSTED!!! I am
beginning to believe that others on this group are correct. All you want
to do is argue. This is another of your attempts to move the target with
a lame attempt to put the ball in your court.

F**CK YOU, DIPSH**T.

John S

 

[miso]

I can't imagine any educated engineer not doing back of the envelope
design on discrete devices, even if it is just a simple gm*ro to
estimate the gain of a stage, gmC for bandwidth, etc. But there are
plenty of clueless engineers out there that just plop stuff down in spice.

If you are selling moderate performance boards by the hundreds, then
just how optimal do you need to be? If you are selling chips by the
hundreds of thousands, then it is a different story. In analog chip
design, you need to meet the spec over mil temp at the minimum power. If
you don't, somebody else will.

 

[[email protected]]

I've never used them and I don't know anyone who does. They are not on

transistor data sheets.

How could you possibly have missed them on the 2N3904 datasheet??? Do you even look at the datasheet? They're on bunches of others, mostly older, too.

S-parameters are used for small-signal

RF/microwave stuff, but only RF parts have s-params available.



We use simple mental models of transistors, which is fine for most

design, without simulation. Complex/tricky things get Spiced, which

includes nonlinear effects that h-params don't include.

The most popular transistor model is hybrid-pi, hands down. Usually as a first approximation prior to simulation, a geometric mean of small signal parameters at the corners of region of operation is sufficient for preliminary performance estimation.

Academia tends to be about 40 years behind engineering practice.



Are you in India? India has a great tradition of academic rigor. The

US tends more to hands-on, hack-and-slash engineering, whatever works.

Simple transistor models are usually good enough for us, at least in

discrete-component designs.

Please cease and desist presuming to speak for how things are done in America. Mnay people have heartburn with your methods.

 

[legg]

Can I have the current picture in the developed countries on h-
parameters? I believe, with so much computing power at their hands,
people should not use h-parameters nowadays. They have no reason to. In
case of complex circuitry, you could do simulations, and in practice, you
use ICs in place of transistors. what is your experience with hybrid
parameters? Could you discuss this with people in the univ. laboratories?

I would mention an important aspect which intrigued me
while I was studying in Univ. The theory books put so much emphasis on
hybrid parameters, but to me, they are good for later analysis, i.e.,
not to invent something new, but when invented, they try to find how
the system work, not for learning electronics principles. And also, in the
practical world I did not come across specific cases of using
h-parameters. I thought - such wastage of time and effort!

It's just one way of looking at things. The discipline is probably not
wasted.

http://www.rfcafe.com/references/electrical/s-h-y-z.htm

RL

 

[[email protected]]

Yeah, mostly older. Of the transistors that we use, most data sheets

have hFE, and only one out of the dozen that I checked had any other

h-params.



http://www.centralsemi.com/PDFs/products/2n3903.pdf



http://www.fairchildsemi.com/ds/2N/2N3904.pdf








Design anything interesting lately? Did you use h-parameter analysis?

Yes, but not "electronical"- too boring. And didn't I espouse hybrid-pi? That is not h-parameter. All that h- y- g- and who knows what else was a force fit into two-port network theory of the time.

 

[rajibbandopadhyay]

Are you in India? India has a great tradition of academic rigor.

India has a tradition of excellent rote-learners. The earlier tradition
of rote-learning verses to impress others (to rise in social rank) is
replaced by the slavish solving of complex mathematical problems of no
originality. There is no love for one's field, only ambition to be better
off than the rest. That is why, you get brilliant engineering students
from the IITs ending up in management, banking and finance. The country
does not have appreciable input in well-cited peer-reviewed scientific
papers. Patents are minuscule. Meritocracy is absent, so meritorious
Indians run away abroad and try never to come back. I have seen the
academia from up close, and the lesser said the better...

 

[rajibbandopadhyay]

I suspect that JL has forgotten just how much he did learn when he was
dragged through all the h-parameter stuff. You may not learn things
that you'll use later directly, but you certainly do learn how to do
circuit analysis.

My precise question was not about learning, but about actual use of, the
h-parameters.
As JL says:

I'd rather use step-by-step
analysis (Thevenin reductions, algebra, like that) so I can get a feel
for what's actually causing what.

h-parameters are a subset of the entire analysis thing. We must restrict
ourselves to discussing about h-parameters

 

[rajibbandopadhyay]

...I am
beginning to believe that others on this group are correct. All you want
to do is argue. This is another of your attempts to move the target with
a lame attempt to put the ball in your court.

F**CK YOU, DIPSH**T.

Why are you and [email protected] personally attacking JL.
He has stated a point, but I did not feel he wanted to pick up an
argument!
Please, I sought your, and others', help with information. Please let
them help me with the information they can provide, which they believe is
correct. It is his personal belief. You state your point and stand back
and let someone else say his.

 

[rajibbandopadhyay]

It's just one way of looking at things.

Please do elaborate your statement. I am a little dimwit.

The discipline is probably not
wasted.
http://www.rfcafe.com/references/electrical/s-h-y-z.htm

I saw the page, but it is just another page, but probably has couple of
citations, which makes it worthwhile:
1. IEEE Transactions on Microwave Theory and Techniques. Vol 42, No 2.
February 1994. Conversions Between S, Z, Y, h, ABCD, and T Parameters
which are Valid for Complex Source and Load Impedances. By Dean A.
Frickey, Member, IEEE

2. IEEE Transactions on Microwave Theory and Techniques. Vol 43, No 4.
April 1995. A correction was printed by Roger B. Marks and Dylan F.
Williams.

JL said so, that other than small-signal RF operations h-parameters are
not very useful. And there are so many parameters, people are bound to be
confused!
I must thank you for all the trouble you took to post the information.
My regards.

 

[[email protected]]

India has a tradition of excellent rote-learners. The earlier tradition

of rote-learning verses to impress others (to rise in social rank) is

replaced by the slavish solving of complex mathematical problems of no

originality. There is no love for one's field, only ambition to be better

off than the rest. That is why, you get brilliant engineering students

from the IITs ending up in management, banking and finance. The country

does not have appreciable input in well-cited peer-reviewed scientific

papers. Patents are minuscule. Meritocracy is absent, so meritorious

Indians run away abroad and try never to come back. I have seen the

academia from up close, and the lesser said the better...

Apparently you fell asleep in civics class too, because India is a paradigmof meritocracy and not its absence. Meritocracy is a political term which describes the selection process for administration positions as being based on standardized test screening, aka civil service examinations, versus personal and/or political party affiliation.

 

[[email protected]]

I asked a simple question, the same as you asked, and ask it again:



Do any of the people who post here design electronics using transistor

h-parameters (beyond the obvious hFE, static beta)?



Some people sure get angry when I ask that question.





--



John Larkin Highland Technology Inc

www.highlandtechnology.com jlarkin at highlandtechnology dot com



Precision electronic instrumentation

Picosecond-resolution Digital Delay and Pulse generators

Custom timing and laser controllers

Photonics and fiberoptic TTL data links

VME analog, thermocouple, LVDT, synchro, tachometer

Multichannel arbitrary waveform generators

Do you ever use transistors for anything other than non-critical switching, current sources and buffers?

 

[[email protected]]

Some of our current sources are critical, by my standards, like

needing to be stable to 0.1% and being very wideband, GHz equivalent

bandwidth.



We occasionally do super low-noise stuff with jfets and, very rarely,

discrete bipolars. Most gain comes from opamps these days. Really fast

stuff often uses PHEMTS.



NMR gradient drivers are current-output amplifiers, from 3 to 120 amps

peak, with PPM noise and pulse flatness. We use mosfets in the power

stages.



H-params are only useful for bipolar transistors, for small-signal,

low-frequency analysis. We don't do much of that any more.



We just did an air flow sensor, based on change in Vbe of a

self-heating TO92 transistor. H-params wouldn't help there, either. It

might work; if it doesn't, we'll just not include that feature on the

product.





--



John Larkin Highland Technology Inc

www.highlandtechnology.com jlarkin at highlandtechnology dot com



Precision electronic instrumentation

Picosecond-resolution Digital Delay and Pulse generators

Custom timing and laser controllers

Photonics and fiberoptic TTL data links

VME analog, thermocouple, LVDT, synchro, tachometer

Multichannel arbitrary waveform generators

You're still not getting it through your thick skull that the classic two-port h-parameters are NOT hybrid pi.

 

[John S]

I read your response as "They are not on transistor data sheets." Is hfe
an h-parameter? Can you at least admit that hfe is on most data sheets?
All I have said is that you are wrong.

HFE, static beta, is on most transistor data sheets. I acknowledged
that.

You did not (in earlier posts). If I am wrong, please show me where.

I did not say that h-parameters are useful. I did not say that I use
them. I did not say that any other person uses them.

I don't care about whether you like them, or use them, or any of your
other excuses to avoid the fact that your statement "They are not on
transistor data sheets" is inaccurate. At least hfe is there. There are
other, low level bipolar transistor, data sheet which still have
h-parameters.

Why can't you accept that?

 

[John S]

On Sun, 14 Oct 2012 09:37:18 -0700 (PDT),



Administration positions? Civil service? I thought we were talking
about electronics design.

Do you think you know more about India than Rajib does?

Do you think *you* do?

 

[John S]

I asked a simple question, the same as you asked, and ask it again:

Do any of the people who post here design electronics using transistor
h-parameters (beyond the obvious hFE, static beta)?

Please show the post where you asked that question.

 

[John S]

I asked a simple question, the same as you asked, and ask it again:

Do any of the people who post here design electronics using transistor
h-parameters (beyond the obvious hFE, static beta)?

What does that have to do with your original statement "They are not on
transistor data sheets" ?

Back peddling now, eh?

Some people sure get angry when I ask that question.

And you wonder why?

 

[[email protected]]

Administration positions? Civil service? I thought we were talking

about electronics design.



Do you think you know more about India than Rajib does?

I know more about the meaning of meritocracy than he does, that's for sure.And claiming to know "more" than him is nearly vaccuous as he seems disturbed- if he's even Indian, or maybe just some f'ing troll from some Anglo waste dump somewhere.

 

[[email protected]]

Having never been to India, certainly not. I have worked with,

roughly, a dozen Indian engineers.



I doubt that a civil service exam demonstrates any sort of meritocracy

in electronics design, anywhere in the world.



It was funny for Fred to insult Rajib for knowing less about India

than Fred does. I wonder how long Fred lived in India.

The very word has its origins in government administration and not non-governmental professions. How damned dumb are you? Here's a brief overview evenyou should be able to understand, unless you question the authority of OPM:
http://www.opm.gov/perform/articles/054.asp