Driver to drive?

John Fields <jfields@austininstruments.com> wrote...

I've designed multi-kilowatt underwater projectors driven by a 50 ohm
source by doing what was necessary to get a conjugate match to the
ceramic.
Click to expand...
Are they, by any chance, used in an application where marine mammals
are exposed to the acoustic output?
 
Winfield Hill wrote:
Guy Macon wrote...

The Supercaps have such a high ESR that you can't get much current
out of them. You also can't charge them fast or discharge them fast,
which can be a real pain when designing high-speed testers for
products that include them.

That used to be so, but isn't any more for some rather amazing
new types. But for the time being they are very expensive.
Click to expand...
Thanks! I haven't worked with one for a while.
 
Rich The Philosophizer wrote:

On Mon, 15 Nov 2004 15:56:06 +0000, Dirk Bruere at Neopax wrote:


Rich The Philosophizer wrote:

On Wed, 10 Nov 2004 21:46:17 +0000, Dirk Bruere at Neopax wrote:



Terry Given wrote:



Dirk Bruere at Neopax wrote:



Paul Burridge wrote:



On Wed, 10 Nov 2004 04:49:20 GMT, Rich The Philosophizer
null@example.net> wrote:




On Tue, 09 Nov 2004 20:42:03 +0100, Frithiof Andreas Jensen wrote:




"Fred Bloggs" <nospam@nospam.com> skrev i en meddelelse
news:418D5DA1.1010609@nospam.com...



Apparently this is still practiced:

"However, a small number of Orthodox rabbis advocate an ancient
practice in which the circumciser sucks



And I thought the Catholic Church had problems ;-))



Nah, they only drink the blood and eat the flesh of some dead guy, who
also happens to be their main icon.

God Forbid they should ever accidentally get their mouth near the
mutilated penis of a helpless baby!




They're not *still* engaging in this odious 'practice' are they? I
thought we'd agreed to ban it. Why hasn't our edict outlawing this
Satanic abuse been observed?



Makes the term 'cocksucking Jew' quite accurate in some cases eh?
Stands right besides 'Xian bugger'.


ROTFLMAO!

The Catholic church might be a better place if one of the commandments
had read "Thou shalt not rape little boys"

Well, Islam seems to have got it partially correct.
They can officially screw 10yr old girls.


Now, wait a minute. I can't believe that there's _any_ religion
that allows sex with underage children. There must have been something
missing in the translation.

Could you shed some light on this matter? Or is it just another
boogeyman thing?

Thanks,
Rich



http://www.islamreview.com/articles/sexinislam.shtml

The Prophet of Islam, Muhammad (pbuh), himself married a child of six (or seven)
years old. Many articles have recently been written about this child bride of
Muhammad.


Oh, marriage. That's an entirely different thing. Maybe I'm a victim
of media programming, but "screw 10yr old girls" is an awful lot
different from an officially, church- _and_ state-sanctioned marriage.
And frankly, other than that, it's really none of our business, if
that's the way they want to run their country. It is their country,
isn't it? Since child abuse and child mutilation are wrong and sinful
and bad and all that, maybe they'll just all go to hell when they're
dead, for being bad, and God will have taken care of the problem.

And never mind the reference is from a book seven thousand years
old or some shit.

But one of the reasons that there are different countries is that,
nasty as their practices might look to us, they are really none
of our damn business. We aren't god either, after all. (well, not
yet. ;-) )
Click to expand...
From the same site
http://www.islamreview.com/articles/sexinislam.shtml

Who needs sex in a hurry but does not want to go through the elaborate ritual of
marriage and the payment of expensive dower? Of course, many people would love
to have this kind of quickie sex without much obligations. No wonder that there
are so many women engaged in the world’s oldest profession just to meet this
demand from depraved men. In modern parlance, we call it ‘one-night’ stand.
Believe it or not, Islam has its equivalence too!

The Islamic counterpart of one-night stand is known as the M’uta marriage. In
this kind of contract marriage, a man simply contracts a woman to sleep with him
for a brief period only. Although the Sunnis have banned the M'uta system, it is
very much in practice among the Shiites. It is quite possible to have a M'uta
marriage every night and kick the woman out next morning. There is no need of
divorce in a M'uta marriage.

--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
 
John Larkin wrote:

On Tue, 16 Nov 2004 00:41:29 GMT, Rich The Philosophizer
null@example.net> wrote:



But one of the reasons that there are different countries is that,
nasty as their practices might look to us, they are really none
of our damn business. We aren't god either, after all. (well, not
yet. ;-) )



So, then, there is no such thing as "human rights."
Click to expand...
There are no such thing as 'Rights' except as a social contract.

--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
 
ahkit1021@yahoo.com (Dummy) wrote in message news:<74bb84c0.0411040204.ae6a9d5@posting.google.com>...
jswenson@mailcity.com (John Swenson) wrote in message news:<29fdb49a.0411031546.575d790d@posting.google.com>...
What actually happened there?

Betcha the radios are microphonic.

Sit one UHF radio on top of the other, disconnect the microphones,
turn the volume up all the way, and enable the transmitter on one.
They will probably howl and sing to each other nicely.

It can be observed with two radios, or when one radio sings to itself.
Speaker vibration - modulates Rx LO VCO - amplified by audio amp -
back to speaker - etc... yuck.

Try tuning one at max volume to a CW carrier. It might not be as
quiet as you think.

UHF radios are more susceptible because the RF frequency is higher.

Less mechanical vibration required to induce the required delta-C
into the Tx VCO circuit. If the VCOs are built on fiberglass FR-4,
it's hard to get them mechanically stable enough.

Higher end radios will usually use a ceramic hybrid VCO to gain
higher performance and better mechanical stability.

Another UHF radio with different design did not show any problem as
mentioned.
'Good' UHF radio uses resonator at VCO tank circuit while the 'bad'
one uses large High Q coils. VHF radio uses chip inductor at VCO tank
and all VCO circuits are shielded. Any chance of coil's magnetic field
interaction with shield and RF caused problem? I'm totally bewildered.
It's good if RF is visible to our eyes so that I could see what
actually had happened between the 'good' and 'bad' radio. How do we
make sure the VCO is mechanically stable?
More shielding? I have no idea of any solution since I do not know the
root cause yet.
Click to expand...
I'm convinced this is related to ultrasonics, not RF interference.
Jingling keys are LOUD at high audio frequencies.

Your "high Q coil" resonant element in the transmitter tank circuit
may be picking up ultrasonics directly, or through the PC board.

Try this test: Enclose the keys in foam padding, while letting them
free to jingle. The padding will absorb some of the ultrasonics,
without changing the RF features significantly.

If the coil is picking up the ultrasonics directly, the transmitter
may be sending out-of-band emissions due to the high modulation
frequency, causing distortion at the receiver after band-limiting of
the channel.

Frank Raffaeli
http://www.aomwireless.com/
 
I sure learned tons of basic electronics trying to get this working... Tkanks again!
 
Reg Edwards wrote:
It is quite possible to have a M'uta
marriage every night and kick the woman out next morning.


==============================

Why wait till next warning?
Click to expand...
It is a solemn undertaking.


--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
 
It is quite possible to have a M'uta
marriage every night and kick the woman out next morning.
Click to expand...
==============================

Why wait till next warning?
 
"Winfield Hill" <hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote in
message news:cn5ntd0249v@drn.newsguy.com...
Winfield Hill wrote...

Some folks will say this linear power regulator design illustrates why a
buck switching converter should be used instead.
Click to expand...
I'd say instead that switchers are too complicated for this application in
the first place and they have the very real disadvantage that it is harder
to take advantage of an intermittent load - because switchers are smaller
and lighter, there is less thermal inertia and they must be rated closer to
the peak load - meaning we have to buy power handling capabilities that we
don't need.

I *would* consider modifying the circuit to use (an) IGBT's instead of
bipolars for the pass transistors; IGBT's are available in bigger packages
than bipolar with screw connectors more suitable to the bus-wiring one needs
for the 150A. The IGBT would have to go 'below' the motor in order to drive
it.
 
Winfield Hill wrote:
In real life they're chemical.
Click to expand...
Yes, but chemical forces are electric forces.

Kevin Aylward
salesEXTRACT@anasoft.co.uk
http://www.anasoft.co.uk
SuperSpice, a very affordable Mixed-Mode
Windows Simulator with Schematic Capture,
Waveform Display, FFT's and Filter Design.
 
On Tue, 16 Nov 2004 11:35:19 +0000, Dirk Bruere at Neopax
<dirk@neopax.com> wrote:

John Larkin wrote:

On Tue, 16 Nov 2004 00:41:29 GMT, Rich The Philosophizer
null@example.net> wrote:



But one of the reasons that there are different countries is that,
nasty as their practices might look to us, they are really none
of our damn business. We aren't god either, after all. (well, not
yet. ;-) )



So, then, there is no such thing as "human rights."

There are no such thing as 'Rights' except as a social contract.
Click to expand...
And of course the people with the power are not interested in signing
such a contract with the powerless. So the only thing that matters is
power.

Thanks for clearing that up.

John
 
John Larkin wrote:

On Tue, 16 Nov 2004 11:35:19 +0000, Dirk Bruere at Neopax
dirk@neopax.com> wrote:


John Larkin wrote:


On Tue, 16 Nov 2004 00:41:29 GMT, Rich The Philosophizer
null@example.net> wrote:




But one of the reasons that there are different countries is that,
nasty as their practices might look to us, they are really none
of our damn business. We aren't god either, after all. (well, not
yet. ;-) )



So, then, there is no such thing as "human rights."

There are no such thing as 'Rights' except as a social contract.


And of course the people with the power are not interested in signing
such a contract with the powerless. So the only thing that matters is
power.

Thanks for clearing that up.
Click to expand...
Correct.
'Rights' have historically been wrested from the powerful by force. See Magna
Carta for a good example. Or maybe the US Constitution.
Our societies are balance of forces.

--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
 
On Tue, 16 Nov 2004 15:55:07 +0000, Dirk Bruere at Neopax
<dirk@neopax.com> wrote:


'Rights' have historically been wrested from the powerful by force. See Magna
Carta for a good example. Or maybe the US Constitution.
Our societies are balance of forces.
Click to expand...
But the US constitution presumes axiomatic, God-given "inalienable
rights" and defines them in the Bill of Rights. They are assumed to be
absolute.

John
 
Winfield Hill wrote:

In real life they're chemical.


All of the neural net stuff I've worked with has been obscure C code.
Click to expand...

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com
 
Frithiof Andreas Jensen wrote:

I *would* consider modifying the circuit to use (an) IGBT's instead of
bipolars for the pass transistors; IGBT's are available in bigger packages
than bipolar with screw connectors more suitable to the bus-wiring one needs
for the 150A. The IGBT would have to go 'below' the motor in order to drive
it.
Click to expand...
IGBTs for low voltage switching?

Unless there's some new device that I've missed, the saturation voltage of
IGBTs is *much* too high. That's why they're aimed at high voltage application.

Gibbo
 
John Larkin wrote:

On Tue, 16 Nov 2004 15:55:07 +0000, Dirk Bruere at Neopax
dirk@neopax.com> wrote:



'Rights' have historically been wrested from the powerful by force. See Magna
Carta for a good example. Or maybe the US Constitution.
Our societies are balance of forces.


But the US constitution presumes axiomatic, God-given "inalienable
rights" and defines them in the Bill of Rights. They are assumed to be
absolute.
Click to expand...
The Constitution only exists because control was wrested from the British by
force of arms.

--
Dirk

The Consensus:-
The political party for the new millenium
http://www.theconsensus.org
 
In article <cnd4md$5nj$1@newstree.wise.edt.ericsson.se>,
Frithiof Andreas Jensen <frithiof.jensen@die_spammer_die.ericsson.com> wrote:
[...]
I'd say instead that switchers are too complicated for this application in
the first place
Click to expand...
I disagree with this. A 150A switcher is not all that hard to do and
would make a lot less heat.

and they have the very real disadvantage that it is harder
to take advantage of an intermittent load - because switchers are smaller
and lighter, there is less thermal inertia and they must be rated closer to
the peak load - meaning we have to buy power handling capabilities that we
don't need.
Click to expand...
No, if you have to make the devices rated at X, you have to make them
rated at X. This is not a capability you don't need. By definition, you
need it.


I *would* consider modifying the circuit to use (an) IGBT's instead of
bipolars for the pass transistors; IGBT's are available in bigger packages
than bipolar with screw connectors more suitable to the bus-wiring one needs
for the 150A. The IGBT would have to go 'below' the motor in order to drive
it.
Click to expand...
I think the one IGBT would cost as much as the 11 transistors in my design
and not be as good of a design. IGBTs that are rated for linear operation
are less common than those rated for switching. The electronics to
control the IGBT would be more complex than my proposed circuit. All
round, I think this application is better with bipolars.

--
--
kensmith@rahul.net forging knowledge
 
On Tue, 16 Nov 2004 08:07:01 -0800, the renowned John Larkin
<jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote:

On Tue, 16 Nov 2004 15:55:07 +0000, Dirk Bruere at Neopax
dirk@neopax.com> wrote:


'Rights' have historically been wrested from the powerful by force. See Magna
Carta for a good example. Or maybe the US Constitution.
Our societies are balance of forces.

But the US constitution presumes axiomatic, God-given "inalienable
rights" and defines them in the Bill of Rights. They are assumed to be
absolute.

John
Click to expand...
How can they be absolute human rights if they are not universally
applicable to all humans?


Best regards,
Spehro Pefhany
--
"it's the network..." "The Journey is the reward"
speff@interlog.com Info for manufacturers: http://www.trexon.com
Embedded software/hardware/analog Info for designers: http://www.speff.com
 
In article <20041116122421.11831.00000732@mb-m16.aol.com>,
ChrisGibboGibson <chrisgibbogibson@aol.com> wrote:
Frithiof Andreas Jensen wrote:

I *would* consider modifying the circuit to use (an) IGBT's instead of
bipolars for the pass transistors; IGBT's are available in bigger packages
than bipolar with screw connectors more suitable to the bus-wiring one needs
for the 150A. The IGBT would have to go 'below' the motor in order to drive
it.


IGBTs for low voltage switching?

Unless there's some new device that I've missed, the saturation voltage of
IGBTs is *much* too high. That's why they're aimed at high voltage application.
Click to expand...
IGBTs lose about 1.5V if you stay well short of the current rating. A
power MOSFET would be a better option because they like linear operation a
little better and have a lot less drop. The problem with both is the
driving electronics.

The gm of the MOSFET is low enough that a source follower's output
impedance is too high. The servo has to be able to swing the gate voltage
fairly quickly. None of the obvious low parts count designs (at least
obvious to me) can make the gate drive needed.

A bipolar transistor like the TIP-35 is about the best answer because they
have about the highest amps per dollar of any transistor. I've go a big
bag full of them so I consider them free.

--
--
kensmith@rahul.net forging knowledge
 
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