Are hybrid parameters useful for design?

[josephkk]

Apparently you fell asleep in civics class too, because India is a paradigm of 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.

Except that it all too easily becomes minimockracy. Which civil service
does become in all nations.

?-)

 

[josephkk]

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

Question their "authority", certainly; challenging govmonk authority is a
treasured US national pastime. I even more so question their capability
to execute such.

?-)

 

[josephkk]

Well, in a twisted way that kind of makes my point: h-parameters are
introduced so that the student can use linear analysis to get a feel for
how circuits work. You already knew.

One of the conceptual models that I find useful is a pair of back-to-back
diodes, with a dependent current source around the B-C junction, possibly
with appropriate base spreading resistance if that's going to matter. It
does a good enough job of predicting most of the pertinent linearized
parameters at any one operating point, and it makes it easy to visualize
what's going to happen if anything reverse biases.

("Good enough job" is defined here as "kinda in the center of the
variation you can expect anyway").

I honestly feel that one should not do SPICE modeling unless you _really_
understand the circuit: otherwise you'll miss something important.

If you SPICE too soon you probably already missed something important.
I'll bet that most of us agree that "feel" for circuits is gained from
lots of working with real circuits rather than from any amount of theory.

?-)

 

[josephkk]

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

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.

Please to remember all of the s, h, y, z, etc parameters are usually small
signal linearizations. They fail at large signal and non-linear
situations which actually are of equal occurrence in design. For instance
they won't help you at all designing a class D or class S amplifier. Nor
much for digital design.

?-)

 

[josephkk]

In the early days of transistors, people built class-A audio gain
chains and stuff, and gain was expensive. We don't do that much any
more, gain is cheap, and one can always do rough math (calculator, or
even in your head) estimates, followed by simulation if additional
precision is needed. So, not many people do the h-param matrix math
stuff that used to be taught. Nobody here has, so far, confessed to
doing so.

I have done so twice. Once on my own work for my edification (a waste of
time), and once for work when i didn't have spice to do the work for me
(rather painful and marginally worth it). Both were long ago.

?-)

 

[Bill Palmer]

Are you actually Sloman in disguise?





--



John Larkin Highland Technology Inc

www.highlandtechnology.com jlarkin at highlandtechnology dot com

[snip malarkey]

No, but you and the others around here are gullible suckers. The OP in this thread , with his obvious fake Indian name, is a racist troll posting through the eternal-september site. As best as I can determine, among his many previous aliases, he is "Charlie E.". So, go right ahead and engage the poser in email conflab about how things are in India from the perspective of some incapable rotting away in a braindead hell hole somewhere.

The OP is certainly NOT "Charlie E". How did you come to such a
braindead conclusion.

And why don't you learn to set line wrap properly?

And fix that fucking double-spaced quoting while he's at it!

 

[rajibbandopadhyay]

]

Mentoring is very important, but so is analysis.

But analytical abilities can also sure be mentored

My son Simon interned with me this summer. I also visit universities
periodically, but my main way of doing that is in print.

Reading can not just compare with mentoring.

]

I have often offered a "drop by" invitation. Anyone who wants to come
and look over my shoulder is welcome... just advise when, I may be
out-of-town.

Really, I think I will have a bout of depression I was to go to Queens
University of Belfast, Northern Ireland, for an M.Sc. in Opto-elec, but
was denied visa (potential immigrant), in 1995. In those days in India
you could never have the best education money could buy. Privatisation of
education has picked up since the 2000's, but is in no way encouraging
like the west.
Talking to you guys, and such prospects of mentoring?! Oh, God! Why I am
a third-world citizen!

 

[rajibbandopadhyay]

[...]

Have posted combined replies to PH's post and yours

 

[John S]

]

Mentoring is very important, but so is analysis.

But analytical abilities can also sure be mentored

My son Simon interned with me this summer. I also visit universities
periodically, but my main way of doing that is in print.

Reading can not just compare with mentoring.

]

I have often offered a "drop by" invitation. Anyone who wants to come
and look over my shoulder is welcome... just advise when, I may be
out-of-town.

Really, I think I will have a bout of depression I was to go to Queens
University of Belfast, Northern Ireland, for an M.Sc. in Opto-elec, but
was denied visa (potential immigrant), in 1995. In those days in India
you could never have the best education money could buy. Privatisation of
education has picked up since the 2000's, but is in no way encouraging
like the west.
Talking to you guys, and such prospects of mentoring?! Oh, God! Why I am
a third-world citizen!

Optoelectronics? Read Phil's book. If you can't get a copy, let me
know and I'll send you one.

How much do you charge for that service?

 

[rajibbandopadhyay]

Optoelectronics? Read Phil's book. If you can't get a copy, let me know
and I'll send you one.

I think its too late for an Indian (never late for a US citizen ) .
Priorities and realities have changed. But thanks for your nice gesture.

 

[John S]

]

Mentoring is very important, but so is analysis.

But analytical abilities can also sure be mentored

My son Simon interned with me this summer. I also visit universities
periodically, but my main way of doing that is in print.

Reading can not just compare with mentoring.

]

I have often offered a "drop by" invitation. Anyone who wants to come
and look over my shoulder is welcome... just advise when, I may be
out-of-town.

Really, I think I will have a bout of depression I was to go to Queens
University of Belfast, Northern Ireland, for an M.Sc. in Opto-elec, but
was denied visa (potential immigrant), in 1995. In those days in India
you could never have the best education money could buy. Privatisation of
education has picked up since the 2000's, but is in no way encouraging
like the west.
Talking to you guys, and such prospects of mentoring?! Oh, God! Why I am
a third-world citizen!

Optoelectronics? Read Phil's book. If you can't get a copy, let me
know and I'll send you one.

What I meant was, if you are giving them away, I want one.

 

[rajibbandopadhyay]

]

Order one from Amazon. I offered one to Rajib on the condition that he
couldn't get one easily himself.

Dear JL,
The book,"All New Electronics Self-Teaching Guide" by Harry Kybett & Earl
Boysen is precisely the book I have been looking for.
The chain that began with my choice to do something about my ignorance in
the history of computing led me here, and you all have led an active role
in making me reach here.
I have also ordered "electronics designs manual" by Markus and hope to
use it for analysis.
I choose this precise circumstance, when one man extends his hands to the
other in pure benevolence, feeling good about it and expecting nothing in
return, to thank you all.
My best regards