Driver to drive?

Jim Thompson · Nov 6, 2004

On Sat, 06 Nov 2004 08:00:47 -0600, John Fields
<jfields@austininstruments.com> wrote:

[snip]

However, it does appear that there's a third alternative, that being
for you to (as you're laboriously working your way through all the
headers you've downloaded) simply skip over the thread with only OT in
the subject line. Simple, huh?

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Kevin Aylward · Nov 6, 2004

Klaus Vestergaard Kragelund wrote:

"Kevin Aylward" <salesEXTRACT@anasoft.co.uk> wrote in message
news:jc6jd.29818$Fu2.1103@fe1.news.blueyonder.co.uk...
Tilmann Reh wrote:
Kevin Aylward schrieb:

I would *not* suggest MOSFETs due to their large G/S capacity,

This is misleading. A bipolar transister with an ft of say, 200Mhz,
at 300ma has a Cin of around 10nf, to wit.

Not in emitter follower circuit.

Ho hummm...

Snip

Ho hummm...A "large" mosfet able to take the power will usually still
have much lower capacitances than a bipolar. It why the standard
device in SMPS are mosfets, not bipolar. You can switch them an
order of magnitude faster. End of story.

Not according to my oppinion.

Which apparently, is as useful as your spelling.

The reason MOSFETs are used in
switch-mode supplies are more that they are easy to drive

One factor, but not the fundamental reason for their use.

(no gate
current). Ofcourse the low capacitance is a second order effect

You obviously don't understand what you have just wrote. They have low
gate current *because* they have low capacitances. Yeah, sure, the lack
of a static current is useful, but not much if you have to drive them
with 10 times the static current in pulses to switch them on an off.

The fundamental reason mosfets are used are that they are much faster.
Its that simple. Your trying to teach your grandpa to suck eggs dude

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.

Ratch · Nov 7, 2004

"John Larkin" <jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote in
message news:0q9ro0tr24l1doulid2gh1qa55t8ru0nhr@4ax.com...

On Sun, 07 Nov 2004 03:57:28 GMT, "Ratch" <Watchit@Comcast.net> wrote:

Such was the feeling in Germany circa 1939.

Yes, but what was the reason behind that feeling,

Standard bigotry.

I thought it was whipped up unreasoned hatred.

and what did they do
about it?

Standard concentration camps and gas chambers.

Shame on them. Ratch

John

Rich The Philosophizer · Nov 10, 2004

On Tue, 09 Nov 2004 18:35:36 -0600, John Fields wrote:

On Wed, 10 Nov 2004 00:24:10 GMT, "Clarence" <no@No.com> wrote:

"Reg Edwards" <g4fgq.regp@ZZZbtinternet.com> wrote in message
news:cmrmrt$609$1@titan.btinternet.com...
Actually I'm an ass. <smiley
----
Reg.

PLONK! ! !

---
When you plonk someone, why do you find it necessary to post that you
did?

That's how he punishes us.

Rich The Philosophizer · Nov 6, 2004

On Sat, 06 Nov 2004 09:45:47 +0000, Daniel Haude wrote:

On Fri, 05 Nov 2004 18:29:09 GMT,
Ratch <Watchit@Comcast.net> wrote
in Msg. <VDPid.572820$8_6.82085@attbi_s04

Hey Ratch, I think you're having such a hard time in this argument because
so far you've failed to properly define the terms "aberrant" and "deviant"
on which you base your argument. But let me help ypu and look it up:

aberrant:
1. Deviating from the proper or expected course.
2. Deviating from what is normal; untrue to type.

deviant:
Differing from a norm or from the accepted standards of a society.

Well, there you are. It all boils down to your personal matter of taste,
or to some very vague concepts as "accepted standards of society".

Well, I'd say "deviating from what is normal" puts about 99.999999999%
of the human population in that category, if "normal" means "in the
middle of the bell-shaped curve".

;^j
Cheers!
Rich

Rich The Philosophizer · Nov 6, 2004

On Sat, 06 Nov 2004 23:58:52 +1300, Terry Given wrote:

Daniel Haude wrote:

On Fri, 05 Nov 2004 18:29:09 GMT,
Ratch <Watchit@Comcast.net> wrote
in Msg. <VDPid.572820$8_6.82085@attbi_s04

Hey Ratch, I think you're having such a hard time in this argument because
so far you've failed to properly define the terms "aberrant" and "deviant"
on which you base your argument. But let me help ypu and look it up:

aberrant:
1. Deviating from the proper or expected course.
2. Deviating from what is normal; untrue to type.

deviant:
Differing from a norm or from the accepted standards of a society.

Well, there you are. It all boils down to your personal matter of taste,
or to some very vague concepts as "accepted standards of society".

Hey, just recently I met someone who rides a monocycle to work every day
(in public!). This behavior certainly fits the above definitions of
aberrant and deviant. Does that mean that public monocycling should be
banned?

--Daniel

Fucking monocyclists, its THEIR fault. Banned? kill them all I say, and
leave their severed heads on poles as a warning to all propsective
deviants - CONFORM. The neighbourhood watch officer will be around to
collect urine samples in the morning.

How is a monocycle different from a unicycle? I rode a unicycle
around the MIT[0] campus the 6 months before I flunked out.

Cheers!
Rich
[0] Minnesota Institute of Technology. ;-)

Mark Fergerson · Nov 4, 2004

John Fields wrote:

On Thu, 04 Nov 2004 08:05:29 GMT, john_c@tpg.com.au (John Crighton)
wrote:

Sorry but you are wrong.
You are confusing the term "union" with employee.
Employees may go on strike whether they are union members or not.
A union does not go on strike.
Employees may go on strike if they wish.
Are we speaking the same language now?

---
Usually, when a shop goes union the entire shop goes union (becomes
what's known as a "closed shop") and the individual employees agree to
allow the union to negotiate any and all matters which may come up
between them (the individual employee) and management. This includes
working conditions, increases in compensation, medical benefits,
punitive actions the company may take against employees (for
infractions of union-allowed rules), severance benefits, everything.

Consequently, after the union comes into power (and it's _just_ that)
no employee may discuss anything with management without union
representation being present.

Without the permission of the union, no single member or group of
members can go on strike, and when the _union_ decides to go on strike
it does. There _is_ the formality of the ratification of the action
by the members of the union, but that's usually a fait accompli since
disagreement with union _management_ (LOL!) is severely frowned upon.

Bottom line is, the union wants to wrest all control from the company
and wants to make sure those dues keep rolling in.

Close. It wants to wrest all control from the _employees_
and charge them for the privelige of making their decisions
for them.

Mark L. Fergerson

Jim Thompson · Nov 4, 2004

On Thu, 4 Nov 2004 15:59:16 -0500, Active8 <reply2group@ndbbm.net>
wrote:

On Thu, 4 Nov 2004 10:52:23 -0800, Joel Kolstad wrote:

"Paul Burke" <paul@scazon.com> wrote in message
news:2uukkhF2d5084U1@uni-berlin.de...
But if it's a school exercise, use the freeware you already have- your
brain. An 8 input map is cumbersome, but not impossible, and you'll soon
realise why most people use HDLs these days.

I wasn't aware that Karnaugh maps could be (systematically) used for more
than 5 variables? Can they be? Back when I was in school we used the
'table method' (I've forgotten the real name) beyond 4.

And 4 is enough to convince people of the value of HDLs, I think!

Yeah, and the K-map apps I've found are only free for lower numbers
of inputs, though some of them are pretty cool apps.

480)460-2350 | |
| E-mail Address at Website Fax

Airy R. Bean · Nov 10, 2004

Top-posting makes sense because you don't need to
move from the "next" button to the "page down" button
and back again to see what's there.

If you peruse ooo 2,000 NG posts every day, then you haven't
got time to pay much attention to every one, but a quick flip
through with the "next" button lets you skim through
for the ones that are relevant.

It is a bad habit of the bottom posters to quote so much that their
response is off the bottom of the screen.

Net Result - THE BOTTOM POSTER'S CONTRIBUTION IS IMMEDIATELY
IGNORED - it can't be seen and is skipped over.

Moral - if you want to be read by others, then top post!

Another reason not to be associated with the bottom-posters is because of
their insulting attitude.

"Guy Macon" <http://www.guymacon.com> wrote in message
news:10p36bk75cvbh02@corp.supernews.com...

A: Because it messes up the order in which people normally read text.
Q: Why is top-posting such a bad thing?
A: Top-posting.
Q: What is the most annoying thing on Usenet?

Tim Williams wrote:

And any newsreader I know of starts you at the top of the message,
both reading and writing.

That's to make it easy for us to trim the quoted material before
bottom posting our reply.

"Posting at the top because that's where the cursor
happened to be is like shitting in your pants because

Michael · Nov 5, 2004

Jim Thompson wrote:

On Thu, 4 Nov 2004 10:52:23 -0800, "Joel Kolstad"
JKolstad71HatesSpam@Yahoo.Com> wrote:

"Paul Burke" <paul@scazon.com> wrote in message
news:2uukkhF2d5084U1@uni-berlin.de...
But if it's a school exercise, use the freeware you already have- your
brain. An 8 input map is cumbersome, but not impossible, and you'll soon
realise why most people use HDLs these days.

I wasn't aware that Karnaugh maps could be (systematically) used for more
than 5 variables? Can they be? Back when I was in school we used the
'table method' (I've forgotten the real name) beyond 4.

And 4 is enough to convince people of the value of HDLs, I think!

Naaah! 8 is easy as long as you are neat with your partitioning. But
I'm going to have to learn some HDL of some flavor or another... a lot
of my recent CMOS analog chip designs require a lot of addressing,
sometimes 12-wide :-(

...Jim Thompson

I'm on your side of the fence, Jim.

I still have grid squares on overhead foils for up to 8x8 (I think),
printed with a laser printer. I used them for years to do all my
K-maps. Did do 8x8's ... several times. Write on the foils with grease
pencil; wipe 'em off when you're done.

Guy Macon · Nov 10, 2004

Airy R. Bean wrote:

It is a bad habit of the bottom posters to quote so much that their
response is off the bottom of the screen.

I see that you have gfailed to read the webpages I referenced,
which address this very point in detail.

Fred Bartoli · Nov 5, 2004

"Kevin Aylward" <salesEXTRACT@anasoft.co.uk> a écrit dans le message de
news

VFid.22885$Fu2.18127@fe1.news.blueyonder.co.uk...

Indeed. How about looking at spice model data

Typically jfets are set to Vtotc=-2.5m (Vto temp co) and Betatce=-500m
(transconductance exponential temp co). i.e. ID = Beta.(Vgs-Vto)^2

Note: Beta = Beta_0 x 1.01 x exp(Betatce.(T-Tnom)). This is the PSpice
formula, and implemented in SS, but probably not implemented in most
other spices other than LTSpice. However, the last time I checked
LTSpice did not implement this PSpice specific temp co for
gasfets/mesfets, unlike SS

Do you know where does the 1.01 factor come from ?

--
Thanks,
Fred.

Ratch · Nov 5, 2004

"Fred Bloggs" <nospam@nospam.com> wrote in message
news:418B95D6.7060308@nospam.com...

Ratch wrote:

Yeah- but you don't mention being against stealing, bullying, or
other antisocial acts because those are characteristics of your
candidate.

Then you obviously did not educate yourself on the facts, did you? Or
else you would know that is exactly what Bush is.

Au contraire, I did. And also his opponent. I made what I thought was
the best selection.

He/she would not be my candidate selection if they were a party to
the above.

You can take GWB and shove him up your ass BTW.

It is YOU who has a problem with him. Just about every citizen of
this planet will be affected to a certain degree by what he does.
You should wish him the best. He has a hard job. Ratch

I want to see him placed under arrest!

On what charge? Get real!

I have seen enough of the kind of
job he does.

If you think he does/did a lousy job, that is not a reason for arrest
or impeachment.

The election has accomplished nothing productive-

What a crock! It determined who will be president for the next four
years.

it has
only succeeded in transforming what was a feeling of total disgust for
Bush into a true *hatred*-

There was that before the election selection.

those idiots in the Congress are dreaming if
they think anyone will be united as a result of the election. You idiots
seem to be overlooking the FACT that probably 55 million voters
*passionately* voted to eject this administration from office- and it
was *true* passion that exceeds anything his dull minded support is
capable of- this is anything but a mandate - it is another Bush atrocity
to even suggest that word has meaning. The same facts that gave cause to
this massive uprising against Bush are still there- the election has
changed nothing!

If there was so much passionate feeling agains Bush, how come so many
young people who registered did not vote? Hard to believe there was such of
a huge groundswell against him if so many of the other electorate did not
vote either. Ratch

>

John Crighton · Nov 6, 2004

On Fri, 05 Nov 2004 22:44:55 GMT, Rich The Philosophizer
<null@example.net> wrote:

<snip>

and the individual employees agree to
allow the union to negotiate any and all matters which may come up
between them (the individual employee) and management.

Not true. You will have to show me that written down somewhere.

---
I don't have to show you anything. On the contrary, if I make a
statement which you think is bogus on _you_ to prove that it is.

Come On. Do you have any idea how ludicrous this is?

snip
Rich

Hello Richard and John,
lets not get all heated up.

I will try an give John an explanation. I think John is
referring to a closed shop scenario.

There are many union members who are quite content
to just pay their dues and let the more active members of
the union get involve in negotiations with management.

There are closed shop environments where *all*
members are just not interested in taking an active
part in negotiations with management due to apathy,
language barriers, embarrassment about voicing their
opinions that they leave all negotiations to the union
head office.

THIS then appears as though union bosses control
the membership.

Lack of communication between union head office and
the union members especially if there is no shop floor
delagate to distribute information to the members also
adds to this *myth* that union bosses control the union
membership.

Regards,
John Crighton
Sydney

Andrew Holme · Nov 10, 2004

Steven O. <null@null.com> wrote

I thought it was implied that since we have flip-flops, the logic is
sequential and not combinatorial. But if I make that explicit -- this
is sequential logic -- then how does the answer to my question come
out?

State machines contain combinatorial logic and flip-flops. The sum of
the parts is sequential logic.

Jim Thompson · Nov 3, 2004

On Wed, 03 Nov 2004 21:30:25 GMT, "Norm Dresner" <ndrez@att.net>
wrote:

"Jim Thompson" <thegreatone@example.com> wrote in message
news:uvfio05fpp6fpknog6tcebo6t7uol1nopb@4ax.com...
On Wed, 03 Nov 2004 20:24:15 GMT, Joerg
notthisjoergsch@removethispacbell.net> wrote:

Hi Rich,

Vt\Vp can vary several hundred percent so this one off batch means
nothing. You can expect huge variations. Your "design" is an accident
waiting to happen.

So, in other words, are you saying, as was I, that coming off the
line, even with care in the production process, there is still so much
variation in the cutoff current that makes it such that you'd have
to individually test each unit? (which, of course, jacks the price
up a bunch)

As Kevin said it is the lot to lot tolerance that really spoils the
broth here. If you take all the FETs from one lot you may be ok. But
that is not a viable concept for long term production.

Processes may be a bit better controlled than 20 years ago but when you
look at the data sheet of, say, ye olde BF245 there should be some goose
pimples on the designer's skin when it is used in a single-FET current
source.

Regards, Joerg

http://www.analogconsultants.com

I don't know the OP's desired current range, but why not an LM317 plus
a resistor? Quite accurate.

I'm the OP. That's fine IIRC for currents in the 5+ ma range but useless
for less than a milliamp. Is an LM317 in a TO-92 package really that much
cheaper than an LM334? Or more effective?

Norm

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| E-mail Address at Website Fax

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