Driver to drive?

Richard The Troll · Dec 7, 2004

On Sun, 05 Dec 2004 11:58:52 -0800, John Larkin wrote:

On Sun, 05 Dec 2004 19:46:44 GMT, Fred Bloggs <nospam@nospam.com
wrote:

Jim Thompson wrote:
On Sun, 05 Dec 2004 19:23:15 GMT, Fred Bloggs <nospam@nospam.com
wrote:

PaulCsouls wrote:

I'll second that. I have the third edition. It provides some good
general guidelines and explanations.

Paul C

Yep- easy to read pablum for schmucks...no wonder you like it..

Goddammit Fred! Take you meds, or be declared extinct ;-)

...Jim Thompson

I am going to amuse myself with a simple jig for measuring VAF...later.

What's a VAF?

(Coupon for one good free insult attached.)

Value Added Fuckwit, obviously.

Rich Grise · Dec 7, 2004

On Sun, 05 Dec 2004 11:57:42 -0800, John Larkin wrote:

On Sun, 05 Dec 2004 12:43:18 -0700, Jim Thompson
thegreatone@example.com> wrote:

On Sun, 05 Dec 2004 19:23:15 GMT, Fred Bloggs <nospam@nospam.com
wrote:

PaulCsouls wrote:
I'll second that. I have the third edition. It provides some good
general guidelines and explanations.

Paul C

Yep- easy to read pablum for schmucks...no wonder you like it..

Goddammit Fred! Take you meds, or be declared extinct ;-)

...Jim Thompson

Yeah, what a sweetheart.

LOL!

Cheers!
Rich

Rich The Philosophizer · Dec 7, 2004

On Mon, 06 Dec 2004 11:47:26 -0800, Winfield Hill wrote:

John Larkin wrote...

Are you claiming that the only way to create a current
is by using a voltage? Shocking, shocking!

Hey, not _that_ much voltage!

Apparently, he's never heard of a dynamo. It's the magnetic movement that
starts the whole thing. All the rest is just modulation.

;^j
Rich

Carl Ijames · Dec 7, 2004

If positive ground is so great for anticorrosion, why did the US auto
industry eventually standardize on negative ground? Are there
disadvantages?

--
Regards,
Carl Ijames carl.ijames at verizon.net

Allan Herriman · Dec 7, 2004

On Mon, 29 Nov 2004 19:40:31 +0100, "Arie de Muynck"
<send.spam.to@spammer.org> wrote:

At least in Europe, most telephone exchanges use a negative voltage
referenced to good old mother Earth.

Why negative? Is it some 'cathodic protection' in case a pinhole leak
occurred?

For > 99.9% of the time, my phone is on-hook, so one of the wires is
at -48V (actually it's about -52V) and the other is within 1V of
earth.

Regards,
Allan

Jim Thompson · Dec 7, 2004

On Tue, 07 Dec 2004 03:20:17 GMT, Rich Grise <rich@example.net> wrote:

[snip]

But when you start talking small-singal,
[snip]

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

Terry Given · Dec 7, 2004

Jim Thompson wrote:

On Tue, 07 Dec 2004 03:20:17 GMT, Rich Grise <rich@example.net> wrote:

[snip]

But when you start talking small-singal,

[snip]

That "small-singal" stuff will get you every time ;-)

...Jim Thompson

Its burned me a few times, but luckily (dy definition really) not badly

Cheers
Terry

Kevin Aylward · Dec 7, 2004

radio913@aol.com wrote:

And how does this contradict the view that the bipolar transistor is
voltage *controlled* which has the nuisance of dealing with the
*effect*
of base current?

Why does it not sink in that there are effects and causes to effects?
Vbe is a cause, base current is an effect.

Why doesn't it sink in that i don't disagree with you
on this point? Maybe you should write a "paper"
on the fact that a voltage induces a current.

You can still consider it a CCCS.

But irrelevant to the issue at hand. To wit, the transistor is a voltage
controlled device. Sure, we can always transform models, but this don't
transform reality.

ALL of the industry uses Beta to describe a
BJT in the data sheets, and NEVER transconductance.

This has already been explained. Transconductance is the same for all
transistor, so why state it?

Bullshit! Gm is the same for all transistors?

Essentially, yes.

It's not even the same for a single transistor, let
alone many of them!

We are discussing the first order approximation, as such gm is
essentially, the same. Its gm=40.Ic at standard temperature.

Sure, there is an internal Re, but over a large current range, the
effect of this is minimal. If we include it, it still don't change the
voltage controlled nature of the device.

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.

Kevin Aylward · Dec 7, 2004

Rich The Philosophizer wrote:

On Mon, 06 Dec 2004 11:47:26 -0800, Winfield Hill wrote:

John Larkin wrote...

Are you claiming that the only way to create a current
is by using a voltage? Shocking, shocking!

Hey, not _that_ much voltage!

Apparently, he's never heard of a dynamo. It's the magnetic movement
that starts the whole thing. All the rest is just modulation.

What part of "excluding magnetic effects" did you miss?

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.

Robert Baer · Dec 7, 2004

John Larkin wrote:

On 6 Dec 2004 03:05:07 -0800, Winfield Hill
hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:

John Larkin wrote...

Winfield Hill wrote:

Second, one will never find Ebers-Moll transconductance parameters
in a datasheet, because being absolutely predicted by kT/qIc,

A 2N2222 has a transconductance roughly 1/15 this value at 500 mA.
Vbe is around 1.3 volts, according to the old green Motorola databook.

Beta, on the other hand, is only down to about 0.4 of its peak value
at the same current.

Your point being?

That the assertion "Gm = kT/qIc" goes to hell a lot faster than "beta
is a constant" does; it can be something like 40:1 off at a
transistor's max rated current. It's actually hard to estimate Gm at
higher currents... the datasheets are generally no help at all. 2N2222
is unusual in that the ancient datasheets had Vbe curves, something
that was rare even in that day and rarer now. Manufacturers *do*
specify min (and often max) beta over the operating range.

There are maybe ten statements that comprise a practical bipolar
transistor model. An engineer should know and use as many as are
applicable to any given situation, but it's silly to apply an advanced
model (or Spice) when all you want to do is turn on a reed relay from
an FPGA pin; in that case, any sensible engineer will use rules 1 and
2 and get on with life.

1. Ic = beta * Ib

2. The b-e junction looks like a diode with nominal 0.7 volt drop.

So stick in a 1K resistor, because it's already on the parts list, and
move on.

John

Check and double check; been doing that since the CK722.

Dec 7, 2004

http://www.zared.com/Regional/Europe/United_Kingdom/Recreation_and_Sports/Transport/Motoring/Advanced_Motorists/

Active8 · Dec 7, 2004

On Mon, 06 Dec 2004 22:10:06 -0700, Jim Thompson wrote:

On 6 Dec 2004 18:44:49 -0800, Winfield Hill
hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:

Jim Thompson wrote...

Sorry to burst your bubble, but gm (for a BJT) is only
a function of current, and NOT the size of the device.

Right, assuming Is is constant across the devices...
(Someone always has to play the devil's advocate).

And WHERE is it that IS figures into gm ???

q
gm = Ie -----
KT

so it figures into Ie

--
Best Regards,
Mike

Frithiof Andreas Jensen · Dec 7, 2004

"Mike Monett" <no@spam.com> wrote in message news:41B4326B.2388@spam.com...

And you can let them know how much you like the new interface here:

Why.do.I.care.?

The IPO is well over and the entire original staff is probably off with
several Millions worth of Eurobonds in their suitcases to look over some
seaside property in Nice.

An evil combine of Reject programmers from MS and Floor Managers from MacD
are left running the shop now ;-)

Paul Burridge · Dec 7, 2004

On 06 Dec 2004 03:11:54 GMT, chrisgibbogibson@aol.com
(ChrisGibboGibson) wrote:

Tell you what......

This is something that has cropped up on this NG with monotonous regularity
over the last few years (do a quick search).

We'll settle it once and for all.

I'll build a circuit using a tranny of my choice. I'll give you *any* data you
want from the datasheet but I won't tell you the tranny. I'll give you the
measured base current and the measured base emitter voltage and I'll also give
you the case temperature after 15 minutes steady state. I won't exceed any
manufacturers maximum parameters.You give me the collector current.

I know *exactly* where my money is on who gets closest. It certainly won't be
the hfe brigade.

Who's up for the challenge?

Go for it, Chris. Sounds like the most exciting thing to happen here
in years!
--

"What is now proved was once only imagin'd." - William Blake, 1793.

Paul Burridge · Dec 7, 2004

On Tue, 07 Dec 2004 03:24:53 GMT, Rich The Philosophizer
<null@example.net> wrote:

On Mon, 06 Dec 2004 11:47:26 -0800, Winfield Hill wrote:

John Larkin wrote...

Are you claiming that the only way to create a current
is by using a voltage? Shocking, shocking!

Hey, not _that_ much voltage!

Apparently, he's never heard of a dynamo. It's the magnetic movement that
starts the whole thing. All the rest is just modulation.

Active8 is similarly ill-acquainted with the facts; perhaps that's why
they get on so well together. :-/
--

"What is now proved was once only imagin'd." - William Blake, 1793.

Rich Webb · Dec 5, 2004

On Sun, 05 Dec 2004 11:57:42 -0800, John Larkin
<jjlarkin@highlandSNIPtechTHISnologyPLEASE.com> wrote:

On Sun, 05 Dec 2004 12:43:18 -0700, Jim Thompson
thegreatone@example.com> wrote:

On Sun, 05 Dec 2004 19:23:15 GMT, Fred Bloggs <nospam@nospam.com
wrote:

PaulCsouls wrote:
I'll second that. I have the third edition. It provides some good
general guidelines and explanations.

Paul C

Yep- easy to read pablum for schmucks...no wonder you like it..

Goddammit Fred! Take you meds, or be declared extinct ;-)

...Jim Thompson

Yeah, what a sweetheart.

Still around here, is he? I never see anything from him anymore unless
he's quoted. Guess I need to cobble together a second-generation kill
file that post-processes and removes the quoted stuff. All in the name
of improving the signal to noise ratio, of course.

--
Rich Webb Norfolk, VA

Active8 · Dec 7, 2004

On Tue, 07 Dec 2004 16:09:45 GMT, Kevin Aylward wrote:

Active8 wrote:
On Mon, 06 Dec 2004 22:10:06 -0700, Jim Thompson wrote:

On 6 Dec 2004 18:44:49 -0800, Winfield Hill
hill_a@t_rowland-dotties-harvard-dot.s-edu> wrote:

Jim Thompson wrote...

Sorry to burst your bubble, but gm (for a BJT) is only
a function of current, and NOT the size of the device.

Right, assuming Is is constant across the devices...
(Someone always has to play the devil's advocate).

And WHERE is it that IS figures into gm ???

q
gm = Ie -----
KT

so it figures into Ie

Not really. It cancels out.

Huh?

--
Best Regards,
Mike

Mark Zenier · Dec 6, 2004

In article <20041206021736.10458.00001120@mb-m25.aol.com>,
K8JLF <k8jlf@aol.com> wrote:

In the USA, you can receive various signals from NIST transmitters (10 MHz
"exactly" is one, I think). However, you must be aware of ionospheric
effects that can cause an apparent frequency shift near sunrise and sunset.

The stations in question are WWV (10Mhz) and WWVH (15Mhz) as far as I know. WWV
broadcasts from Fort Collins, Colorado, and WWVH is based in Honolulu, Hawaii
if I recall correctly. They at least used to be on other frequencies as well.
Mostly good for setting a watch by. They broadcast a tone every second, and a
different one on the minute. I have a piece of equipment somewhere in my garage
that uses their signal to generate a timing output to control something else
(designed for traffic control I think)

No, the atomic clocks use the WWVB VLF transmitter running at 60 kHz.

Try Atmel for the receiver ICs, originally from Telefunken.

The modulation is in the NIST publications 432(?). It's on
their web site. Or in _Reference Data for Radio Engineers_.

Mark Zenier mzenier@eskimo.com Washington State resident

John Fields · Dec 7, 2004

On Tue, 7 Dec 2004 16:19:58 -0000, "Dave Moore"
<dave.m.moore@baesystems.com> wrote:

Hi All,
Ok, this is my problem. I need to run 2 laptops from a 12v 'leisure'
battery via an inverter. The battery is a 12v 110Amh item and the inverter
is a 600W continuous/ 1500W surge item.

The trouble starts when plugging in the laptop AC/DC adaptor into the
inverter output. Even without the laptop connected, this trips out the
inverter, which then starts to click (sounds like a relay switching) in and
out. During this period of about 20 seconds or so it appears that the
inverter is trying to supply enough current but fails and retries. The LED
on the laptop adaptor gets increasingly bright, and then (say after 20
seconds), the inverter stops clicking and works correctly. I can then plug
the adaptor into the laptop and then all is well.

Whilst this gets me running, I'm not happy with this. It appears that the
adapter is pulling a lot of current when power is applied. Once the laptop
is up and running the current load is much less. Does anybody have any cheap
suggestion as to how I might get round this?.

I can think of 2 approaches:
1). Try to limit the current to the adapter. This would have to be done in
the 240V AC part of the system and frankily I'm a bit scared of playing
around with this!.

2). Alternatively, I could replace the 19v laptop adaptor with something
else which doesn't require such a large start-up current.

Any ideas?.

---
Add a 6V 110AH battery in series with the 12V battery you now have and
blow off the inverter.

--
John Fields

Rene Tschaggelar · Dec 7, 2004

Galsaba wrote:

Anyone can refer me to where I can see a schematic diagram of the above?

Sample and hold what ?
The light ?

Rene
--
Ing.Buero R.Tschaggelar - http://www.ibrtses.com
& commercial newsgroups - http://www.talkto.net

Driver to drive?

Richard The Troll

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Rich Grise

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Rich The Philosophizer

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Carl Ijames

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Allan Herriman

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Jim Thompson

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Terry Given

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Kevin Aylward

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Kevin Aylward

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Robert Baer

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Active8

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Frithiof Andreas Jensen

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Paul Burridge

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Paul Burridge

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Rich Webb

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Active8

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Mark Zenier

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John Fields

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Rene Tschaggelar

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