Driver to drive?

[John Fields]

On Mon, 15 Nov 2004 21:23:29 GMT, donaldun@spamfreepearce.uk.com (Don
Pearce) wrote:

For the other bit, as you say the cables are short so they don't enter
into the situation. The 50 ohm source is transformed by the |MATCH|
bit in the middle - whatever that is - to the conjugate of the load
impedance. It is that conjugate impedance that drives the load, not
the 50 ohms.

---
By that criterion, then, it's the end of the cable that's driving the
load! Picky, picky, picky, but I get your point!

Thanks,

--
John Fields

 

[JeffM]

Electoral expenditure rules with teeth, so that multi-millionaires
can't buy up TV time to push electoral misinformation into the brains
of the couch potatoes.
Bill Sloman

Agreed, but I'd go farther than that.
As part of the licensing procedure for commercial broadcast stations
I'd include a requirement for the donation of a certain amount of free
time during election years (perhaps restricted to a month or so before
the election)
John Fields

We used to have something like this.

An additional piece was called the Fairness Doctrine.
Reagan's FCC decided it wasn't necessary any more.
Bill Moyers did a good segment on this for this election cycle.
Commercial outlets only reported on the horse-race aspects of campaigns;
if you wanted to hear about actual issues, that time had to be purchased.
Public broadcasting was the exception (barely).

for each/all of the candidates who have managed to meet
certain requirements; perhaps 100,000 signatures. Dunno... haven't
worked it out yet. What do you think?

Yup. We do need uniform electoral processes.

The smell of what happened in Florida 2000 and Ohio 2004 pointed this out.
The no-paper-trail voting thing is another sore point.
With rolling blackouts in California when Enron et al were playing games,
some of us were reminded of the fragility of electronic data.

The Canucks have it right: KISS for voters--paper ballots and a marker.
Put any complexity on the vote-counters' end; not much--they count by hand.
Having one guy from each party per precinct
(more is OK, as long as representation is equal) keeps things honest.

Latency in the USA isn't a huge deal; we have til Jan 20.
If we're going to use computers, it should be to verify eligibility
and (mostly) eliminate provisional ballots--not for actual voting or counting.
All they actually needed in Florida was a big poster in each polling place
with a good graphic of the back of a marginal punch-card ballot
saying "Clear your m***********g chads, morons"
--or better punching equipment; no problems with punchers in L.A. County.

Of course, if Katherine Harris had actually followed Florida law
when laying out the 2000 ballot, that would have been nice too.
My all-time biggest gripe:
reinventing the wheel, without checking what standards are already in place.

 

[John Fields]

On Mon, 15 Nov 2004 22:04:22 GMT, Michael Noone
<mnoone.uiuc.edu@127.0.0.1> wrote:

Hi - I need to drive a fairly power hungry circuit (I think a couple
hundred ma, but I'm not positive just yet on that) from the output of a 555
in astable mode. My first thought was a darlington transistor or a mosfet.
Does that seem sensible? I don't know what speed it will be operating at
just yet (haven't been told), but I get the feeling it should be fairly
fast, probabaly in the MHz range, and I'm not sure if high power
darlingtons or fets can operate that fast. So, I was wondering if somebody
here might be able to lend me a little guidance? A part number would be
great, as I have to admit I'm slightly new to electronics (I'm a second
year EE at UIUC)

---
It would probably be better if you got all your ducks in a row before
you start looking for specific hardware but, in general, a 555 is not
a good oscillator for what you want since it's rated at 500kHz fmax as
an astable. Also, "in the MHz range" is pretty broad. Can you get a
little closer?

--
John Fields

 

[Rich The Philosophizer]

On Mon, 15 Nov 2004 13:06:04 -0700, Mark Fergerson wrote:

They're all old familiar saws because every person
ever born has to make the relevant decisions.

I'd go even deeper. There's only one story, and all the
rest is
retellings. You just have to be able to see the mapping
function.

Yup. OTOH once you get the central theme, having the
mapping functions takes all the fun out of hearing the
stories as you know how they'll turn out. OTGH you are able
to recognize when you're immersed in somebody else's story
and have the opportunity to rewrite the script on the fly...

Well, that's what Free Will is all about. With true Free Will,
everybody is making up their own story on the fly all the time,
everybody is immersed in everybody else's story, it's all
improv, and everything works because each instant is seen
_and_ _felt_ for what it really is _right now_, so every action
is appropriate. And all of the information is available, if you
can get past the memes. Or deeper, imprints.

The nonviolence meme sometimes tries to take over
completely. Do not allow it to unless you believe you have
no right to survive.

I need to go into this in some depth, I think. From what
I understand of the nature of a meme, it has no choice but to
try to take over completely. But not letting it take over
completely doesn't necessarily mean discarding all of the
information that might be available there.

Right. The meme wouldn't have propagated if it had no
value at all.

The way you say this it sounds like the equivalent of saying
that the HIV virus or Pox virus or whatever must have some
value. I can't see that, other than value to itself

But overweighting it means you don't survive.

This is either a total non-sequitur or totally bass-ackwards.
Your survival is built-in. The problem was when people started
thinking and meming, they started making up stuff, thinking
their brand-new intellect could do a better job of surviving
than what Body has had a billion years' experience learning.

I guess things were going OK before people got gods and stuff,
huh? ;-)

At this point, the discussion seems to be taking a couple of
directions simultaneously, which is why I've been labeling my
responses.

It may seem that way to you, but ISTM that there's a
central theme, namely Survival and its potential
subordination to many outside influences.

OK, I think what the memes do, is deceive you as to what is actually
a real threat to your actual survival.

Your fear, an element of your "survival instinct" doesn't think,
or evaluate, or judge, or anything like that - it just goes,
"DANGER!". And then the mind kicks in and starts analyzing what's
going on, and decides that two gay guys in San Francisco are a
threat to your survival. And uses your fear against you. What
you're probably fearing is the unknown, that got stuck when you
were about 1 1/2 YO when you _know_ there's a monster under the
bed, and Dad says, "Don't be so stupid. Shut up or I'll give you
something to cry about." So you shut up so that you don't get
smacked, and the fear gets a lid clamped on it and spends the
rest of your life suffocating. And when it tries to tell you
it's dying here, you make it go away again with more drugs or
movies of politicians or war or whatever you have been convinced
will ensure your survival, when your survival hasn't been
threatened since the day you were shit out of Heaven into Hell
here, with the cold and rough and noise and bright and SMACK!
Welcome to the world, kid!

Something about ending troubles by opposing them.
Don't most
sentient beings already know that "opposing," as in
"taking up arms against", might actually _exacerbate_ the
troubles in
the sea?

Note that I said "when appropriate", which may be
difficult to determine. I prefer to oppose violence by
getting out of the way or redirecting it so that nobody gets
hurt (Aikido), but sometimes that isn't an option like when
facing a gun sans cover, and the only options you have are
to shoot back or submit meekly. I never choose the latter
since I feel that I deserve to survive at least as much as
the hypothetical shooter. If he started it, I shoot to kill.

Well, my counter to this is, how did I ever put myself into
a situation where I'm being confronted by some guy who wants
to shoot me? Howcome he wants to shoot me?

If you say, oh, it could just happen at random walking down
the street minding your own business, I'll claim, which nobody
can refute or prove other than by saying it's claptrap, is
that that will not happen unless there is some kind of reason
for it - some lesson that you need to learn. According to
the New Paradigm, victim and perpetrator are just two concurrent
incarnations of fragments of the same spirit. Also, children
are the incarnation of their parents' own denials. Which is
pretty obvious, if you do a little observing. ;-)

This is another place where I want to go into some depth, on
a couple of different subtopics, like violence/nonviolence,
meme/nonmeme, cause and effect, and that sort of thing.

Sure. Slow weekend for me.

Like, how would a given person know if they were playing
a particular meme? Or whatever the verb would be. Like
executing
a program, or "acting out" a script, I guess.

By thinking about why they're doing what they're doing.
There's a major difference between reasoning and
rationalization causality-wise.

Well, yes, of course. But the ones who are acting out the
script think that they're seeing the whole picture, and that
anybody who says otherwise is a $HATED. The quickest way is
simply to undeny. And stay consciously present for emotional
movement, allowing the Light of Unconditional Love to heal
the hurt.

Would he get pissed off if you offered contrary information?

Probably, because that's what we're trained to do. Memes
take root largely because of the emotional investment
aspect, and we've already discussed how easily emotion
usually trumps mentation.

Well, emotion is _supposed_ to call the shots. Original Error
was Mind thinking that it had a better way. And whenever
something didn't feel right, Mind blamed Emotion and cast out
that part that didn't feel right. This was fundamentally wrong,
and is the cause of all of the pain and suffering there is.
About 50 years ago, God clued up that there was a problem that
didn't get fixed last time he sent a savior, so this time He
went all the way to the root of the problem and found out that
it was His mistake all along, and he's been trying to weasel
out of blame, and doing a pretty good job at it, except that
it's been killing almost everything. He has stopped doing
that, but reality can't respond instantaneously, because
we're so much denser in the physical form that electrical
spirits.

God's got a website devoted to saying he's sorry, and he
needs our help to recover all the Lost Will.

I see memes/scripts/programs as mental parasites that
steer us in directions that favor _their_ propagation,
including stimulating our emotions so that we protect them.
I note that yours don't piss you off as easily as do some
others' here...

Oh, that's because I'm so disgustingly highly-evolved. ;-)

On the other tack, how did I get myself into a situation
where
somebody wants to shoot me? Maybe if we'd yelled and screamed
at each other for awhile, and maybe slap each other until
somebody gets knocked down, then go buy each other a beer?
Isn't that how "real men" do it? ;-)

Yup, and that should tell you what I think of guys that
have to settle arguments with guns. But such people do
indeed exist, and being prepared for them in advance is
simple prudence.

Well, whatever I've been doing has been working. ;-)
Not going to gang clubs in East LA is probably one effective
thing. ;-)

Then there're those who will want to kill you not because
of anything you personally did, but because they perceive
you as a member of a group they want to eliminate. You
cannot reason with them until you disarm them, and often not
then, because their motivation is not amenable to reason.

Oh, them, I'm just hiding from. At the most selfish personal
level, it really isn't any skin off my teeth if they're having
a war or invasion or whatever you want to call it on the other
side of the world. I'm having sloppy joes for lunch. ;-)

Exacerbation is relative to how bad you think your
current difficulties are. To take an extreme example, if
you're a well-treated slave, freeing yourself will be
engender a certain amount of inconvenience, and you'll have
the opportunity to freely starve to death afterward, but you
have to decide if freedom is worth the inconvenience.

For me, the bottom like would be, can I walk away and not
be punished for it? Other than, of course, the "punishment"
of needing to figure out a way of feeding myself, which is
not all that difficult.

Now, if you're up to your ears in debt, with a wife and
a couple of kids and maybe an ex and couple of her kids
all depending on your paycheck, that's a kind of slavery
all its own.

This is another of those issues where there's a spectrum,
from slavery to freedom. I'm in a situation right now where
moving would be very inconvenient, and I put up with what I
claim is a lot of BS from stupid and just plain insane
people,
but from another POV, I'm sitting on the goose that's laying
the golden eggs. Well, in a manner of speaking. I guess she's
sitting next to me, or something. Maybe she's conceptual,
like
the tooth fairy, or Santa Claus.

So, your "slave collar" isn't too tight? That's your
business, subject to your perceptions, of course. I'm just
pointing out that most people wear their slave collars
voluntarily after weighing the pros and cons of removing them.

Slavery need not be physical either; there is slavery to
ideas.

I guess it still comes down to "do I have the power to exercise
my options as I see fit?" If not, then you're in a learning
experience, I guess.

There really is a Santa Claus, however, and this is proven
by the fact that a couple of years ago he brought me an RV.
He was in the form of an ordinary man, of course, but when
you look at all the aspects of the situation, there is no
other possibility than that he was an earthly incarnation
of Santa Claus himself.

This has nothing to do with anything, which is why I try
to refrain from getting too too in-depth while so stoned
that it's difficult to play find-your-foot, or peek-a-boo.

In a way it does; most of the discussion so far has to do
with people acting out negative memes. Your Santa was acting
out a positive meme.

Fighting back or even ducking an attack is an effort,
and might make an attacker go to greater lengths, but your
only other option is to meekly absorb the attack.

Or even, and this is the wackiest of all, _cause_
them?

Your suspicion that opposition causes the troubles
you're trying to decide whether or not to struggle against
is the result of extreme Liberal propaganda falsely
equalizing all such struggles. It is a meme designed to
convince you that you have no right to survive.

Oh, boy. Did you intentionally word this this way to push
_my_ "I
am not a meme" button? ;-)

Yes.

But you _do_ recognize that most of what runs through our
minds is a collection of memes, right? At least, until we
learn to think about what we're thinking, and why.

They don't _have_ to be. They might _look_ indistinguishable,
and this can be the tricky part. There's more to everything
than just what it looks like.

Once again, there are little struggles,
and big struggles. Differences of opinion are why there
are horse
races. It's all a continuum, and picking one side or the
other
and adamantly refusing to see the POV of the other side
simply
limits one's own options.

Sure. But you have to be ready to question the
implication that all PsOV are equally valid. Then, you have
to decide what criteria to use to determine validity. But
that flies in the face of so many memes that most people
can't do it at all, and default to their own particular meme
set.

Yeah, this is why alcoholics and other addicts have to hit
bottom before they'll change their mind. Unfortunately, most
of the memes - now that I think about it, "meme" and "addiction"
are almost interchangeable - don't result in the personal
destruction of their host, but rather just a lot of general
malaise all around. And it's so much easier to just blame
somebody for your problems than to accept that what you were
told, that has been the foundation of everything you've based
your life on since you can remember, is wrong.

This is, in my alleged mind, significantly different from
seeing
both PsOV, and picking one because the other one simply
sucks. ;-)

According to what criteria? Which side is refusing to
examine its fundamental assumptions because of emotional
attachment to those assumptions? The usual answer is, "all
of them".

But when you're meme-free, you can deal with the other people's
assumptions, and you don't have to have those "attachments,"
although, what's really wrong with attachments? I think that's
just another scare tactic word. For example, I'm really glad
that all of my parts are firmly attached! (except my head, of
course, thank you peanut gallery ;-) )

Anyway, each person evaluates each situation according to the
criteria that suit that particular individual. That's what
Free Will is. It's really the only way to properly run a
universe. Each entity intrinsically knows what is right for
it. Humans, however, have been teaching the opposite for
quite some time. There simply are no two situations where
the exact same response is appropriate. Any time you act
based on a script rather than what the situstion really
is, right now, you're doing yourself a disservice.

Mr. Shakespeare was obviously channeling a higher
wisdom, but
when you look at the _really_ big picture, even his
inspiration
pales in comparison to the latest revelation extant,

No, it doesn't. "Outrageous fortune" is his way of
delineating those disruptive circumstances that stand out
from the usual run of intrusions Nature has always handed
us, like mosquitoes, gout, and bad weather. Some of them you
can prevent/control/mitigate beforehand, and some you can't.
Some you can affect after the fact, and some you just have
to avoid or run away from, like tornadoes.

OK, now, in one sense, we're talking about entirely different
things, if you're relating a tornado to the 9/11 attack.

Not really; in my following paragraph I mention ignoring
the fact that the opposing entity is human, meaning ignore
their emotional (memetic) motivation and just look at the
mechanics.

Obviously, one could only say "I caused the tornado" if one
were god itself. But tornadoes do seem to preferentially
target trailer parks.

Yup.

Have you ever heard of that ubiquitous character, The School
Bully? Have you ever heard the ULs about one of his victims
sneaking up behind him and sucker punching him right splat
in the nose with a carpenter's hammer?

Yup. No UL; I did that once, except I used a brick.
Fucker never bothered me again.

That's what 9/11 was.

Only now, apparently, Al has only pissed off the bully even
worse. Now the bastard's got _guns_!

Unless you believe that somebody went to all the trouble
of inventing the OBL tape from whole cloth, in which case,
what in the Universe could have been their motivation,
he says very clearly what the motivation for the 9/11
attack was. The neos all call him a liar, and call it
bullshit, but if that's the case, who did the tape, and
why?

Which tape? Not that it matters; analyze his claims for
_objective_ validity. That removes any need to speculate on
its origin. IOW, who benefits? More below.

But interpersonal (and international) relationships
seem very different because of the nature of the disruptive
agent; you seem to have trouble making distinctions between
_their_ justifications and yours. Simply ignore the fact
that the other side is human and look at the effects
directly; would you take a tornado on the chin, figuring it
was your fault because you didn't know you should have been
elsewhere?

Ah - this is the point I was talking about about a paragraph
or two ago. There's tornadoes, there's vandalism, there's
bloody mass murder, and there's war. Unless there was
some kind of official declaration of war, the 9/11 attack
was no more than a heinous criminal attack in precisely the
same manner as the McVeigh/OK City bombing, and the vandals
should have been arrested and prosecuted, except for the
inconvenient
fact that they were all already dead.

That kind of operation requires organization beyond what
the perps could manage alone, _and_ motivation beyond what
will fit within a few minds. Hence the need to find the rest
of the organization and put it out of business.

I wrote that paragraph because so very many people act
solely as a result of the meme assortment in their minds;
they never ever think anything through and might just as
well _be_ the forces of nature I compare them to.

Therefore assessing your chances of survival, and
devising strategies to assure it, come out to the same thing
in both cases. That kind of person can no more devise
counterstrategies on the fly than a tornado can. In fact, if
you know their meme sets, they're easier by far to
manipulate than any natural force because nature is subject
to uncertainty. Minds set in stone are never uncertain.

This is true. Fooling with Mother Nature, now that's an
entirely different issue! One thing you have to admit,
Mother Nature is one horny mama! <leer, snort!>

It would certainly have done to at least have a freaking
_investigation_ before going charging off half-way across
the world with guns blazing, intending to kick ass and
take names later. Especially when "Kick ass" includes
the wanton slaughter of thousands of people who probably
hadn't ever even heard of the World Trade Center anyway!

Do you even notice your choice of phrasing here?
"Charging with guns blazing", "kick ass and take names
later", "wanton slaughter", and so on? Where did you get
those memes?

Oh, it's all from the "America is being taken over by the
fascists and turning into the Fourth Reich" meme-set.

The real issue here is the cause of the attack. You
seem to believe that 9-11 is justifiably the fault of
America, and I don't.

I never said "justifiable."
I'll thank you to refrain from supplying words while alleging
to quote me.

That's why I said "seem", rather than supplying a direct
quote. You seem to spend lots of effort "justifying" it.

Maybe you're using a different form of the word "justifying"
it. I thought maybe it could be _explained_, but that doesn't
_excuse_ anything. When you psychoanalyze a Postal Psycho or
Serial Killer, you try to learn _why_ he did the things he
did, but that doesn't mean he's not still _accountable_.

The "fault" of the airplane crashing into the building is
clearly the fault of the guy, now dead, who drove the
airplane
into the building. So obviously, none of them was killed
by a drunk driver. Right?

But the underlying "cause" of the attack, AKA why did that
crazy barstid and his team hijack an airplane and fly it
into the building? According to one report, it was a pop
in the snoot in response to a decades-long pattern of
oppression, harassment, whatever you want to call it.

"One report" which has been inflated into a righteous
jihad against the Great Satan. You've accepted this meme
wholeheartedly. Why?

It may _look_ like I've accepted some meme wholeheartedly, but
from my POV, it looks like you're running one on me. ;-) I
said "according to one report". I haven't done anything towards
the righteous jihad against the Great Satan other than to root
for the underdog, which my mom, bless her soul, trained me to
do. This makes it hard to enjoy a game when the home team is
winning. )-; And I mentioned that this might be a valid other
way of looking at things, at least to see where the other
guy's coming from.

I mean, if you can find out what a guy wants, and in so doing
save lives, why not? Do you really want to see thousands more
sacrificed at the altar of George Bush's Fragile Ego?

It was a response, unless you want me to stretch my mind
to encompass the possibility that somebody spent hunderds
of thousands of dollars, and sacrificed people, to perform
a simple mugging?

Just for the express purpose of pissing off the most powerful
destructive force ever known in the entire history of
Existence?

Yup. But that's not the desired _end_ of the effect; what
happened next, in _your_ mind? What memes fired off in
direct response? Re-examine your choice of phrasing a couple
paragraphs above.

Even the Japanese, after they found that the declaraiton
of war
didn't get to the prez. on time, realized, "Uh-oh. We've
awakened a sleeping giant."

Yup. They were also a static target. Al Qaeda isn't.

The base at Pearl Harbor was the twin towers. Al Quaeda is
Japan. Would they not have realized that such an attack would
piss off the US?

What purpose could that possibly accomplish?

As I asked, "Who benefits"? Think it through carefully,
keeping in mind that that somebody else's idea of "benefit"
might be different from yours or mine.

Well, yeah - they did it to piss off the US, to trigger their
"go to war" meme, so they can play themselves off as innocent
victims, and recruit thousands into their Jihad armies.

Or, they might have believed that it might have had the
desired effect of making somebody in the US go, "Hey - is
there somebody that doesn't like us? Why could that be?",
although I'd have to admit, that's a pretty unrealistic
expectation.

You have been propagandized into failing to see this
the other way around;

Oh, I see. Now _I've_ been propagandized.

We _all_ have; it just took better in some of us than
others due to our pre-existing meme set (and hopefully, our
ability to analyze it for objective sensibility).

Oh, memes are nothing. Wait till you get to your own _imprints_.

those who participated in that attack are the ones who
"exacerbated" the past low-key business in the Middle East
into actual warfare. This is of course exactly what they
wanted; they have an Armageddon Complex as destructive as do
Xtians.

How stupid have you been programmed to think these people
are?

"Stupid" = "have a different meme set from mine"? That's
how I analyze the usual usage of that word.

They do not have lower-than-average intelligence. They do
however want different things to happen in the future than
do most of the rest of us. They see the cost of making this
happen differently than do you and I.

Well, I see a very deep, broad-based meme here in all this "US
vs THEM" crap. Each person probably wants pretty much the same
things as the next. A home, a family, friends, and most of them
have some kind of church. It's the insane rulers that have to
be watched out for, and well, the bottom line is, if people
get whipped up into a frenzy by their leaders, well, they're
just going to have to do their own karma. Most of them are
grown-ups and supposedly qualified to make up their own mind.

I guess I jumped the gun on this one too. Are you saying
that there was some "low-key business" and they just decided,
up out of the clear blue sky, "Hey, let's launch an
unprovoked
assault on the Biggest Most Powerful And Destructive Military
Machine In All Of Creation, just to watch them bomb us back
to the stone age!"

Rich, the ones who planned 9-11 are not the ones being
bombed anywhere, as you've noted. That's a "benefit" of
their plan. The fact that others are being bombed is also a
benefit, acording to their criteria, because of which memes
fire off in response to it in suitably prepared minds.

OK, so they are pretty sharp - kill two or three birds with
one stone.

Yeah! Sounds like a _real_ fun plan!

Not! (in case anyone was wondering.)

Except those of the planners, who are enjoying the hell
out of it.

And yes, you have shed some new light on the issue, and I'm not
as het up these days as I have been about the whole thing anyway -
I think I just recently popped one of my own spiritual karmic
zits, so I'm feeling much better now. ;-)

Cheers!
Rich

 

[ddwyer]

In article <gi9ip0t8ermfpg6fm0uki9lmpbl6c2ieok@4ax.com>, John Fields
<jfields@austininstruments.com> writes

On Mon, 15 Nov 2004 21:23:29 GMT, donaldun@spamfreepearce.uk.com (Don
Pearce) wrote:


For the other bit, as you say the cables are short so they don't enter
into the situation. The 50 ohm source is transformed by the |MATCH|
bit in the middle - whatever that is - to the conjugate of the load
impedance. It is that conjugate impedance that drives the load, not
the 50 ohms.

---
By that criterion, then, it's the end of the cable that's driving the
load! Picky, picky, picky, but I get your point!

Thanks,

I was involved with sonar in the 60s but the following still holds true.

If you are operating into a uniform non reflective loads like sonar then
careful matching will give efficient transduction with a largely real
load and low transducer heating.
For testing purposes with unknown loads a dynamic matching system to
give a conjugate match would be ideal in practice it may/will be easier
to swamp reactive load with a resistor to protect the transducer and
driver.


--
ddwyer

 

[Active8]

On Mon, 15 Nov 2004 19:29:00 GMT, Rich Grise wrote:

On Mon, 15 Nov 2004 02:20:15 -0500, Active8 wrote:

On Sun, 14 Nov 2004 10:15:13 -0800, Tim Wescott wrote:

Kevin Aylward wrote:


That is, a Colpits oscillator is when, topological, there are caps
across base emitter and collector emitter, with an inductance from base
to collector (Colpits), or where the caps and inducters are swaped
(Hartly).

Argh. Yes, I got the transistor in there wrong -- I was concentrating
on the nifty notion that you draw the circuit free of any entanglements
from bias networks, then you ground whatever point is most convenient
for you.

Oddly enough I almost never do that in practice -- its only when I have
an audience that I screw up in such a stupid way.

@#$%! See Kevin Aylward's comments -- I got my transistor in there
wrong. All other comments apply.

.------o------.
| | |
| --- |
| --- |
C| | ---
C| o-----v \--.
C| | |
| --- |
| --- |
| | |
'------o----------'

What about - I've seen this, but it's an n-fet, not an npn. The c-e
cap isn't part of the tank, per se, but it's a bypass - ?

Yes - the cap is a short for RF, so from the RF's POV, it's the same
circuit.

+---------+
| |
| Bypass |
|/ ---
+----------+------| ---
| | |> |
| --- | |
| --- | |
C| | | |
C| +--------+---- out |
C| | |
| --- |
| --- |
| | |
+----------+------------------+-- GND, IIRC

created by Andy´s ASCII-Circuit v1.22.310103 Beta www.tech-chat.de

Cheers!
Rich

Then there are those osc tranny specs/notes where they hardly add
any components - it runs off junction caps. I think the output cap
is reflected to the input as inductance in significant enough
amounts to affect the tank.

It's one of the amps that do.
--
Best Regards,
Mike

 

[Michael Noone]

John Fields <jfields@austininstruments.com> wrote in
news:gqaip05m63dd5gp1kqff59tg5iovonhnn5@4ax.com:

On Mon, 15 Nov 2004 22:04:22 GMT, Michael Noone
mnoone.uiuc.edu@127.0.0.1> wrote:

Hi - I need to drive a fairly power hungry circuit (I think a couple
hundred ma, but I'm not positive just yet on that) from the output of
a 555 in astable mode. My first thought was a darlington transistor or
a mosfet. Does that seem sensible? I don't know what speed it will be
operating at just yet (haven't been told), but I get the feeling it
should be fairly fast, probabaly in the MHz range, and I'm not sure if
high power darlingtons or fets can operate that fast. So, I was
wondering if somebody here might be able to lend me a little guidance?
A part number would be great, as I have to admit I'm slightly new to
electronics (I'm a second year EE at UIUC)

---
It would probably be better if you got all your ducks in a row before
you start looking for specific hardware but, in general, a 555 is not
a good oscillator for what you want since it's rated at 500kHz fmax as
an astable. Also, "in the MHz range" is pretty broad. Can you get a
little closer?

Damn - I did not know about that limitation of the 555. I may be
entirely incorrect about that speed, as I said it was just a guess. I
was given very vague specs on Friday for it. I'll try to find out more
specific information tomorrow. For higher speeds, what would I use in
place of an 555? The first thing that comes to mind is a
microcontroller, say an AVR or a PIC. Sorry for being so vague, I
promise I'll get better information as soon as I can. Thanks,

-Michael

 

[Joerg]

Hi Michael,

Usually I take 1/6th of a Hex Schmitt trigger and use it as an astable.
The data sheet says how that is done. For PWM control a FET, transistor
or whatever can be hung from the input to ground to steer the pulse
width. A CD40106 may be best here because you can run it at 10V or so
which provide enough drive for a FET.

Of course this is only useful if it is a loop structure. A Schmitt is
not suitable for setting exact pulse widths. If you have a micro
controller on board anyway you can always create a loop to set the pulse
width.

Regards, Joerg

http://www.analogconsultants.com

 

[Joerg]

Hi Michael,

Forgot to mention: What I meant were clean CMOS versions of Schmitt inverters such as the 74HC14 or CD40106.

Regards, Joerg

http://www.analogconsultants.com

 

[Tim Wescott]

Active8 wrote:

Then there are those osc tranny specs/notes where they hardly add
any components - it runs off junction caps. I think the output cap
is reflected to the input as inductance in significant enough
amounts to affect the tank.

It's one of the amps that do.

There are any number of ways to make an oscillator using the parasitic
components in the transistor. Other than overtone crystal oscillators
which use the parasitic C-B capacitor to form a Hartley oscillator
(actually a tuned-base tuned-collector oscillator) between the crystal
on the base and the tank circuit on the collector I haven't actually
used any of that sort.

--

Tim Wescott
Wescott Design Services
http://www.wescottdesign.com

 

[Tom Seim]

John Fields <jfields@austininstruments.com> wrote in message news:<u4uhp0let3kvog2n3h1cnq13fm6mk7uifm@4ax.com>...

On Mon, 15 Nov 2004 17:47:48 +0100, Rene Tschaggelar <none@none.net
wrote:

Piezos are never driven with 50 Ohms, rather with a a bipolar
emiterfollower or Opamp, and some series resistor.

---
Not necessarily true.

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.

Wanna see some pictures of them in action?

By all means!

 

[Winfield Hill]

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.


--
Thanks,
- Win

 

[John Larkin]

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."

John

 

[David Lesher]

Why the concern/spec over PF? Can you even notice that load on the
grid when you have 100's of gas-discharge street lamps running?
--
A host is a host from coast to coast.................wb8foz@nrk.com
& no one will talk to a host that's close........[v].(301) 56-LINUX
Unless the host (that isn't close).........................pob 1433
is busy, hung or dead....................................20915-1433

 

[Rich Grise]

On Mon, 15 Nov 2004 17:44:26 -0800, Jean-Marie Vaneskahian wrote:

Mission Accomplished! I have a CO Detector Wirelessly Sending Out
Alarm Status

I finally got the battery operated Carbon Monoxide detector to also
send a trigger to the house alarm system!

I want to thank everyone who pointed me in the right directoion and
also those that came up with novel ways of making this work.

Here is the setup:

I have already in place in my single family home hardwired
interconnected smoke alarms that are also hardwired to my monitored
alarm system. What I do not have is any Carbon Monoxide detectors. I
found very nice battery operated Carbon Monoxide detectors at "Home
Depot" that would work great as standalone units. I wanted to have
these nice battery operated Carbon Monoxide detectors also fault
independent zones on my monitored alarm system.

My alarm system has wireless contact closure transmitters. If the
wireless transmitters detect a contact closure on the screw terminals
it sends a zone faulted alarm to the alarm system.

The battery operated Carbon Monoxide detectors have two LEDs on the
face, one that blinks every 30 seconds to indicate normal operation
and one that is RED that ONLY turns on in an alarm condition.

I took the PCB out of the battery operated Carbon Monoxide detector
(it snaps right out) and soldered 2 – 24 Gauge, 12 inch wires onto the
anode and cathode of the red LED on the back side of the PCB.

With my voltmeter I saw that the voltage across the red LED when the
battery operated Carbon Monoxide detector when into an alarm condition
was 1.7 – 1.9 Volts. The LED would also flash rapidly because the
voltage would go on and off. In other words the LED would stay fully
lit if it always received the 1.7V and would only turn off when no
voltage was present.

At this point you can really simplify your subsequent circuit. One
of the LED leads should go to a resistor. On the other side of
that resistor, you'll find full supply voltage when it's on.
Or maybe the other way around - the thing is, you've got a
series circuit in the CO alarm of the LED, a resistor, and a
transistor, not necessarily in that order. The voltage across
the LED and resistor will swing from 0 to the full 9V, probably.
You can then run this straight to the 555 trigger input with
a capacitor, with either a pullup or pulldown resistor (depending
on which way it's connected) and a pair of clamp diodes.

Or, if you're feeling brave, you don't really even need the
555 - just have a capacitor charge through a diode, and
discharge through a resistor for 16 seconds. That's sometimes
called a "Poor Man's One-Shot" or PMOS, circuit.

Have Fun!
Rich

 

[Rich Grise]

On Mon, 15 Nov 2004 17:44:26 -0800, Jean-Marie Vaneskahian wrote:

Mission Accomplished! I have a CO Detector Wirelessly Sending Out
Alarm Status
....
My alarm system has wireless contact closure transmitters. If the
wireless transmitters detect a contact closure on the screw terminals
it sends a zone faulted alarm to the alarm system.

A transistor switch gives the same effect as a contact closure.

If the sense lines are DC biased, then with the right polarity,
you could solder those wires directly across the COA output tranny
and toss that whole Rube Goldberg Klooge!

Well, except for that flashing/time delay bit. But could your
alarm base station be programmed to accept an intermittent
contact closure?

In any case, I bet you learned a lot more this way!

Cheers!
Rich

 

[Rich Grise]

On Tue, 16 Nov 2004 02:56:58 +0000, David Lesher wrote:

Why the concern/spec over PF? Can you even notice that load on the
grid when you have 100's of gas-discharge street lamps running?

The I^2*R losses in the wires are very real, indeed. And more than
they would need to be with the power factor corrected.

Cheers!
Rich

 

[Rich Grise]

On Mon, 15 Nov 2004 22:15:26 -0500, KILOWATT wrote:

With the four 1n4007 wired in series, i
should get a peak reverse voltage of about 4Kv isn't? For what i know, a
diode is destroyed once it's PIV is exceeded. I think i missed something
when studying the basic operation theory of a diode. ;-) TIA for any
useful reply.

Just "exceeding the PIV" doesn't automatically destroy a diode.
In fact, that's how Zener diodes are _intended_ to be operated -
in inverse breakdown.

What lets the smoke out is exceeding the power dissipation
ability of the chip. A 1N4007 with 1KV across it and 50
microamps flowing through it would have to dissipate 50
milliwatts, which it would hardly notice, especially
considering that they'll dissipate right about a watt in
the forward direction, at one amp, just in normal operation.
With a proper heat sink, or if the pulse doesn't last very
long, they can pass a surprising amount of current and live
to tell about it. ;-)

Hope This Helps!
Rich

 

[PaulCsouls]

On Tue, 16 Nov 2004 02:23:19 +0000 (UTC), kensmith@green.rahul.net
(Ken Smith) wrote:

For sim. I use LTSpice. For product schematics, I use Orcad for DOS. For
me, Spice is mostly about checking my math.

--

I heard rumors that Orcad for DOS was now freeware.

Paul C

 

[Rich Grise]

On Tue, 16 Nov 2004 05:07:31 +0000, Bob Myers wrote:

"KILOWATT" <kilowatt"nospam"@softhome.net> wrote in message
For what i know, a
diode is destroyed once it's PIV is exceeded. I think i missed something
when studying the basic operation theory of a diode. ;-) TIA for any
useful reply.

I've also given almost the verbatim answer in s.e.d.

KILOWATT, please cross-post instead of multi-posting this sort of
question, so that the answers can propagate to both groups for
the benefit of more people.

You'll note that I've crossposted this one.

If a thread becomes more group-specific, there are more than enough
people around USENET who will be more than happy to kindly remind you
to set your followups appropriately. ;-)

Thanks,
Rich