Maker Pro
Maker Pro

Bifilar Wound Balun Transformer

R

rickman

Jan 1, 1970
0
Notwithstanding Feynman's quote, "nobody really understands QM", that's
more accurately the problem, as I also understand it.


Sure! My work is done:
http://vk1od.net/antenna/shieldedloop/
Well, maybe not *my* work, but... helpful nonetheless. Lots of excellent
analysis on his website.

Tim

Certainly this is a good page, thanks. But that's not the same as
designing one... or helping. Still, thanks.

Rick
 
B

Bill Sloman

Jan 1, 1970
0
And John doesn't like doing that kind of work.
In the electronic design business, we seldom really understand what
we're doing, at the first-principles level. We usually work further up
the abstraction stack. We usually buy parts, read data sheets, and
connect them up. It's actually unusual to *make* a part. [1]
Do you not see how your posts make you look?
I posted pics of actual isolating transformers made with micro-coax.
And some nice sub-ns-risetime 100 volt pulses that were pumped through
similar transformers. Why would a customer be turned off by something
that works?
A sub-ns rise time into a 50 ohm load implies equivalent leakage
inductance in the 10s of nH.
[1] invite interesting tales of actually making components.

  At least you actually do something, not like a good many here that
would like to make people think otherwise.

  I spend more time at actually experimenting with what works the best
instead of fighting with PC software that only gets it close but not
good enough.

   I just love those that talk shit and most likely hardly even toucha
piece of equipment. When they do I am sure

Jamie's confidence is touching. In fact what he is saying is that he
is envies people who have better luck when they fight with the PC
software, and wants to think that they are less fortunate at the
bench. It's a slightly corrosive point of view, and may make him a
difficult colleague.
they're all thumbs and
fingers with it and most likely end up getting some one else to do it
for them and take all the credit for it.

It does happen, but not very often. Most people with enough sense to
get a PC to do what they want it to have enough sense to also make a
soldering iron do what they want it to.
   Those guilty of this need not to step forward, I already know who
most of you are.

He's made up whatever it is he uses instead of a mind.
 
B

Bill Sloman

Jan 1, 1970
0
That particular transformer in the photo was driven by a gaasfet. It
worked fine, made really pretty isolated pulse outputs, about 500 ps
edges. About 2000 of those transformers trigger most all the various
gadgets at NIF.

But what's the inter-winding capacitance? I could probably work it
out, but you presumably know the exact number.

Whatever it is, 2000 of it is going to be a lot of capacitance across
a galvanic isolation barrier.
 
B

Bill Sloman

Jan 1, 1970
0
It's just a few pF. The winding is just a few inches long.

That's a "don't know".
The 2000 outputs are separate triggers, "clients" (things that we
trigger) scattered all over the site. The isolation is only to break
ground loops and keep jitter down.

Of course. But it's capacitance across a galvanic isolation barrier,
and - as such - injects AC current into the isolated ground. If your
clients aren't keeping track of that, they aren't doing their job
right.

155.52-MHz seems surprisingly low. I would have thought that there
were faster standard frequencies that they might have adopted, with
correspondingly lower edge jitter. And it's not "your" paper - you
aren't first author, and clearly didn't write it.

It may be one of the few published papers that list you as an author,
which is no small thing, but it's not "your" paper.
 
B

Bill Sloman

Jan 1, 1970
0
Of course not. It slows things down, even when it's possible.

This isn't always true. There is some fiddling that is easy in
simulations, and pretty much impossible in practice.
And besides, I like to solder once in a while.

There are better reasons.
 
J

Jamie

Jan 1, 1970
0
Bill said:
That's a "don't know".




Of course. But it's capacitance across a galvanic isolation barrier,
and - as such - injects AC current into the isolated ground. If your
clients aren't keeping track of that, they aren't doing their job
right.




155.52-MHz seems surprisingly low. I would have thought that there
were faster standard frequencies that they might have adopted, with
correspondingly lower edge jitter. And it's not "your" paper - you
aren't first author, and clearly didn't write it.

It may be one of the few published papers that list you as an author,
which is no small thing, but it's not "your" paper.
You're not racking up many points either.

Jamie
 
B

Bill Sloman

Jan 1, 1970
0
Ground loops are usually low frequencies, like 60 Hz.

50Hz in some countries, 400Hz in aircraft. However circulating current
at an unusual frequency can create problems too.
If your

My clients do their jobs right, and so do I.

So you tell us. You presumably convinced them of your competence, or
maybe you were just the low bidder.
You don't have a job.

What's that got to do with their competence? Or yours for that matter?
My timing modules work; you don't.

You claim ownership of a paper of which you were a minor author.
Should we trust your claims about your timing modules?
 
J

John S

Jan 1, 1970
0
You're not racking up many points either.

Jamie

And you think you are? Go away and leave these professionals alone. At
least they understand the subject whereas you don't even know your job
function.
 
J

John S

Jan 1, 1970
0
At least you actually do something, not like a good many here that
would like to make people think otherwise.

Well, we agree on this.
I spend more time at actually experimenting with what works the best
instead of fighting with PC software that only gets it close but not
good enough.

So, you spend more time experimenting than designing things yourself.

Get a calculator, paper, pencil, and some knowledge, and design
something without a computer, imbecile. Nobody said you needed to use a
computer. Most professionals here began designing without a computer.
I just love those that talk shit and most likely hardly even touch a
piece of equipment. When they do I am sure they're all thumbs and
fingers with it and most likely end up getting some one else to do it
for them and take all the credit for it.

Like you, right? People like you tend to join a crowd of similar people.
That's why you are only tolerated here. Find your own crowd.
Those guilty of this need not to step forward, I already know who
most of you are.

Of course. You are omnipotent.
 
F

Fred Abse

Jan 1, 1970
0
Fred Abse a écrit :
For a simple one, just as it is:
use a TLine/RLC tline and between the 2 ""shield/ref plane" connections
you just tie the magnetizing inductance, with maybe your core model
(losses, non linearities, hysteresis,...)

Thanks, I'll try that
 
B

Bill Sloman

Jan 1, 1970
0
On 11/4/2012 3:37 PM, Jamie wrote:


Like you, right? People like you tend to join a crowd of similar people.
That's why you are only tolerated here. Find your own crowd.


Of course. You are omnipotent.

I think you meant omniscient. Which Jamie may believe - but only
within the rather circumscribed universe of discourse - and the rest
of us know to be quite a way from the truth.
 
B

Bill Sloman

Jan 1, 1970
0
Why would I care what you trust? Do you think the NIF paper was faked?

It seems most unlikely, but - accepting that the paper is honest -
which I'm more than happy to do - all it says is that you were the
supplier, and your gear worked well enough to be satisfactory in the
application.

As you have mentioned here, when physicists publish about electronics,
they usually have exaggerated ideas about how good their electronics
is and how close it is to the state of the art. I've got a couple of
comments in Review of Scientific Instruments that criticise
particularly flagrant examples of this kind of defect.
We did two systems for NIF, got some awards, made some money, learned
an awful lot. That's what sometimes happens whan you DO stuff.

I've noticed. That's one of the reasons why I'd like to do some more
stuff, and why I'm frustrated by being confined to doing stuff I can
afford which solves the kinds of problems that I can dream up without
much help from the outside world. I learned a great deal when I was
working on the Cambridge Instruments Electron Beam Tester, and I
enjoyed the process.
 
B

Bill Sloman

Jan 1, 1970
0
I guess there's nothing stopping one from making a couple of gigahenry
inductors coupled with K=1.

That's the joy of simulation. You can test ideas that would cost a
mint in superconducting wire and liquid helium if you wanted to try
them out on the bench.

The are applications where that kind of expenditure on real parts
might be justifiable.
 
J

Jamie

Jan 1, 1970
0
Bill said:
That's the joy of simulation. You can test ideas that would cost a
mint in superconducting wire and liquid helium if you wanted to try
them out on the bench.

The are applications where that kind of expenditure on real parts
might be justifiable.
I get the idea that a simulator is the only source for any inclinations
you come up with..

Jamie
 
J

Jamie

Jan 1, 1970
0
Bill said:
I think you meant omniscient. Which Jamie may believe - but only
within the rather circumscribed universe of discourse - and the rest
of us know to be quite a way from the truth.

Speak for yourself, you hardly have enough energy in that singularity
on your solders to think, let alone operate a keyboard and wipe your
ass. You spend all your time searching the web for that black hole of
yours to suck up in hopes that there is some shred of information you
can use to mislead the public with great deception.

Don't be including the general public in your punitive deceitful
appearance. Many here don't know any better, they are simple minded
sheep lost in the propaganda orchestrated by the likes of you.

Jamie
 
J

Jamie

Jan 1, 1970
0
John said:
And you think you are? Go away and leave these professionals alone. At
least they understand the subject whereas you don't even know your job
function.
Professionals? If you only knew what one was.

Impersonation is more your style.

Jamie
 
J

Jamie

Jan 1, 1970
0
Bill said:
50Hz in some countries, 400Hz in aircraft. However circulating current
at an unusual frequency can create problems too.




So you tell us. You presumably convinced them of your competence, or
maybe you were just the low bidder.




What's that got to do with their competence? Or yours for that matter?




You claim ownership of a paper of which you were a minor author.
Should we trust your claims about your timing modules?
Just for you slow-man.

Jamie
 
F

Fred Bartoli

Jan 1, 1970
0
John Larkin a écrit :
It's cool to stick a micro-ohm resistor somewhere in a circuit to
sample current, and follow that with a 1e6 gain amp with infinite
CMRR.

I like to build analog error computers into my circuits too, so I can
graph error or goodness on the same plot as actual signals.

I do tend to worry about power dissipation and real-world stuff in
sims, where it just doesn't matter. A couple of 1 ohm resistors make a
good divider, but I worry about the current, so I use 1Ks.

On complex designs (well simulations) it's better to worry about matrix
conditioning and in this regards a 0V voltage source and a CCVS in lieu
of your 1µohm and 1E6 gain VCVS is much better.
I have some applications where convergence is sometimes hard to obtain
and I sure wouldn't want to make the situation worse than it needs to be.
 
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