Driver to drive?

[RogerN]

If I remember correctly, college was 25 years ago, if I had 5V and 6V in a
741 OpAmp with a gain of 1, I'd get 6V out, a 1V differential plus a 5V
offset of the non-inverting input. I'm wanting rid of the offset to get the
differential out with respect to ground.

Is this a 741 problem or would all differential amps have the non-inverting
voltage offset?

 

In sci.physics Le Chaud Lapin <jaibuduvin@gmail.com> wrote:

On Sep 13, 7:05?pm, bg_fisted <bg_fis...@hotmail.com> wrote:
On Sep 13, 2:54?pm, Le Chaud Lapin <jaibudu...@gmail.com> wrote:
But this is your doing, your choice: You refuse to give any details,
but what few details you have given in this thread are inconsistent
and sound unrealistic, then when pressed for details, you dodge giving
real answers, but you continue to take the attitude that we're all
wrong, and then you conclude that we are "predisposed" against new
ideas? Hey, it doesn't work that way. First show me an idea that has
merit, show that it works, and give real answers, not vague hand
waving.

There is already sufficient history in this thread and elsewhere that
a significant percentage of pilots have preemptively rejected any
claim to anything that might be new.

-Le Chaud Lapin-

Like the man said, first show an idea that has merit, show that it
works, and give real answers, not vague hand waving

Here's three simple questions for you:

What would your fly-by-wire GA class airplane be able to do that any
modern GA airplane like the Cirrus SR22 can't do?

What materials would you use to contruct your airframe?

If you encounter significant turbulence, what is the first thing
you do and why?


--
Jim Pennino

Remove .spam.sux to reply.

 

[Nico Coesel]

Joerg <notthisjoergsch@removethispacbell.net> wrote:

Eeyore wrote:

That's like most pubs. Break-even on most meals but the millisecond you
order a drink they've got ya.

In the UK it's more the other way round.


Well! Do they have good food in pubs there?

duck and run ...

A few years ago the company send me to Wales (in the UK) for a few
days. I was more than a bit worried about the food. But it turned out
even a small pub can serve an excellent meal for a reasonable price. I
just order woater to go with it

--
Programmeren in Almere?
E-mail naar nico@nctdevpuntnl (punt=.)

 

[Nico Coesel]

"Jon Slaughter" <Jon_Slaughter@Hotmail.com> wrote:

I have a few ideas(one in particular that I'd like to use this trick on)
that I believe could be useful. One definitely has potential and solves a
well known problem(nation wide if not international problem that plagues
people... basically deals with property theft). For sake of argument, assume
the idea has some ground instead of assuming it is worthless.

The first thing a good idea needs is someone willing & capable of
selling it.

--
Programmeren in Almere?
E-mail naar nico@nctdevpuntnl (punt=.)

 

[Bob Eld]

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message
news:48CD3CC6.7DB7874E@hotmail.com...

Bob Eld wrote:

"Phil Allison" <philallison@tpg.com.au> wrote

** Read the fucking data -

you RIDICULOUS STUPID CUNT !!

** Go get fucked - you pile of vacuous pommy shit.

you blind as a fucking bat POMMY ASSHOLE

..... Phil

I see Phyllis is getting "technical" again. Maybe we can all learn from
her
erudite scientific discussion.

I'd like to know why Nat Semi quote 94V (no signal) and 84V with signal.
Since
signal level isn't specified, are they saying 1mV of input @ 94V will kill
it ?

Someone at Nat Semi needs to be shot.

Anyway, I suggested a better option, also from National.

Graham

Probably second break down. As you know, bipolars can only take a reduced
amount of current for a reduced amount of time as the collector to emitter
voltage is increased. The highest voltage is specified at a low collector
current and high collector currents are specified at reduced collector
voltage, power dissipation not withstanding.

Second breakdown occurs in the region of both high current and high voltage
on the device for a specified amount of time. Power amplifiers, power supply
pass elements and similar applications require close attention to second
breakdown. I suspect the 94 volt number is with quiescent current only. An
unspecified signal could send the device into the second break down region
when driving a load.

It does seem like a nutty way to specify max voltage though. Max voltage
should ALWAYS include worst case max current under load, or actually under
short circuit, current limiting conditions if you want the device to
survive.

 

[Mike Monett]

John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

The neon won't fully discharge the cap, so the rate will be
higher.

Yes, I realized that just after posting. Searching google for the
extinguishing voltage gives values all over the map. But I think the
bulb will light at about 90V and go out around 60V. So the equation
should be

dt = C * dv / dt
= 0.047e-6 * (90 - 60) / 1e-6
= 1.41 seconds

or thereabouts. The small voltage drop should have little effect on
a 12KV electrostatic filter.

And the firing voltage won't be dependable, especially if the bulb
is in the high side.

I mentioned it should go in the ground side to prevent corona. The
firing rate will vary with different bulbs, and probably other
factors such as temperature. The cap will also have a tolerance. And
you monitor the firing visually, so it's not going to be anywhere
near the accuracy of a dvm.

But it's just a monitor, basically to alert you to problems. The
current drain of an electrostatic filter can vary by many orders of
magnitude, depending on leakage on the insulators from dirt or
contamination, ambient humidity, how much corona there is from sharp
points, etc. So it's more than good enough for the application.

My biggest problem is mounting the filter in the window and trying
to keep the rain out. Raindrops hit the window ledge and make a fine
mist. This gets sucked into the filter and shorts the high voltage
to ground. I was trying to measure the voltage by holding a grounded
lead near the electrode and estimating how much gap it would jump.
But the loud bang made me nervous every time it arced over. The NE-2
seems like a much better idea. Simple, reliable, and much quieter

John

Mike Monett

 

[Mike Monett]

Monitoring the current in an elecrostatic air filter can be a
problem.

If you use an external dvm in series with the high voltage lead, you
are exposed to a potential arcover that could give a very bad jolt,
or even cost your life.

If you put the dvm in the ground lead, accidentally removing one of
the leads can place dangerous voltages on the remaining connections.

US patent 7258729 has a neat solution. It uses a NE-2 bulb is in
parallel with a capacitor, which goes in series with the high
voltage. (It probably should go in the ground lead to help minimize
corona from sharp points and small lead diameter on the
connections.)

The capacitor can be adjusted to suit the expected current.

The patent uses a 0.047uF cap. Assuming the NE-2 fires at 90VDC, and
the current drain is 1uA, the bulb would fire every

dt = 0.047e-6 * 90 / 1e-6
= 4.23 seconds

which is fast enough to monitor visually.

This is a very simple solution to what can be a difficult problem.

Best Regards,

Mike Monett

 

[Mike Monett]

Mike Monett <None@here.adr> wrote:

dt = C * dv / dt

Sorry, typo. Should read

dt = C * dv / I

But you knew that already

 

[Phil Allison]

"Bob Elderly Fool "

Probably second break down.

** BOLLOCKS.

Much more likely to be simple Vce breakdown if one of the output devices is
ever subjected to 90 volts or more.

The LM3886 chip *includes* fast SOA limiting to prevent "second
breakdown".




...... Phil

 

[Mike Monett]

John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Sun, 14 Sep 2008 17:47:49 -0500, John Fields
jfields@austininstruments.com> wrote:

So you're measuring it something like this:

Vin>---+
|
[49.5R]
|
+-----<<---+
| |
[0.5R] [SCOPE]
| |
GND>---+-----<<---+

or, maybe:

Vin>--+--<<--+
| |
| |
[50R] [1/100]-->>--[SCOPE]--+
| | |
| | |
GND>--+--<<--+----->>-----------+

JF

No, just a 40 dB, 18 GHz SMA attenuator. The scope is a Tel 11801
with a 20 GHz sampling head.

John

That still doesn't explain how you hooked it up.

The photo cleverly doesn't show the entire waveform, so you can't
tell if it's a positive or negative-going pulse, or what the duty
cycle is.

Assuming the gates are driven from a low impedance, that probably
means a pulse generator with 50 ohm source impedance, perhaps
driving an attenuator to further reduce the Thevenin impedance at
the gates. The case of the generator is at ground, so the 2N7002
sources would be at ground also.

So the only thing left to wiggle is the drains. And that is a
problem.

The attenuator is a 40 dB 18 GHz attenuator, so it has an input
impedance of 50 ohms.

There doesn't seem to be a coupling cap between the drain and the
attenuator, since the waveform shown goes from zero to +0.5V.

The attenuator case is grounded, so you are probably not connecting
the center pin of the attenuator to +50V and driving the outside
shield with the drain of the 2N7002. That would mean lifting the
scope off ground, which is difficult to do at 1GHz.

If you connected the input pin directly to the drains of the 2N7002,
you would need to connect a 50 ohm resistor to a 100V supply in
order to get a 50V swing at the drain.

But that would burn out the attenuator if the 2N7002's were left
off.

But with the 2N7002's turned on, the 50 ohm drain resistor would
dissipate 200 watts.

That would mean you are using a very good high frequency resistor,
since there is little or no overshoot in the waveform. That would be
very expensive.

You might be cheating a bit by switching the circuit on briefly to
capture the waveform, then turning it off to save the resistor. But
that seems unlikely.

The 2N7002's are only rated for 60V VDSS, so there's not much room
for other approaches that might involve higher supply voltages.

So it's not definite how you are getting the waveform, but it is
possible to eliminate many of the options due to bandwidth, cost, or
power considerations.

That leaves few remaining alternatives, so your circuit has to be in
one of them.

So what's your trick?

Best Regards,

Mike Monett

 

[Jenn]

In article <8phrc4p4eb9clm3m2gsm6ps59hodaglvkp@4ax.com>,
John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

On Mon, 15 Sep 2008 01:39:36 +0100, anything@contractorcom.com wrote:

On Sun, 14 Sep 2008 20:30:40 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:


John Larkin wrote:

Goofy never goes out of fashion.


What do you expect out of burnt out old musicians? If they were any
good, they would be too busy to hang around a newsgroup, and making
fools of themselves.

Ahem. The same caould be said of burnt out (or would that be 'fried')
old electricians.

Pete

In both cases, what matters is the quality of the product.

John

a

 

[Mike Monett]

John Larkin <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

Why is that a problem? It is, as I've said, transformer coupled.

So why was JF fooling with direct coupling. And why did you say you
couldn't post the schematic?

Anyway, I figured you had to be using a transformer while taking a
shower.

I got XNews to retrieve the whole thread, and found it. Should have
done that at the beginning

You invert the output signal to show a positive-going pulse. That's
what threw me off.

And a very low duty cycle to avoid burning out the attenuator.

So what's your trick?

Like I said: two 2N7002's driving a transmission-line isolation
transformer, with brutal gate drives. The point being that mosfets
can be made to switch a lot faster than their datasheets usually
suggest.

Next time, we're going to use a GaN fet. That should really
scream.

Nice. Please post the pictures so we can enjoy!

John

Mike Monett

 

[Jenn]

In article <RpWdnYKp7tPoSFDVnZ2dnUVZ_srinZ2d@earthlink.com>,
"Michael A. Terrell" <mike.terrell@earthlink.net> wrote:
a

anything@contractorcom.com wrote:

On Sun, 14 Sep 2008 20:30:40 -0400, "Michael A. Terrell"
mike.terrell@earthlink.net> wrote:


John Larkin wrote:

Goofy never goes out of fashion.


What do you expect out of burnt out old musicians? If they were any
good, they would be too busy to hang around a newsgroup, and making
fools of themselves.

Ahem. The same could be said of burnt out (or would that be 'fried')
old electricians.


There are old electricians.

There are bold electricians.

There are no bold, old electricians.

Electricians don't design electrons, anyway.

Some electrical engineers do have a wicked sense of humor.

 

[Damon Hill]

"Martin Riddle" <martin_rid@verizon.net> wrote in news:kAjzk.149$3e1.68
@trnddc02:

http://projects.dot.state.mn.us/35wbri

Looks better, and somewhat more robust, than the old design.
Two spans instead of one, as well.

Okay, that's one big bridge in short order, how many hundreds
more we got that're about to fall down on no notice?

--Damon

 

[TheM]

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message news:48CDC654.2688CF07@hotmail.com...

John Larkin wrote:
Don't start up that European superiority nonsense again. What it makes
you is fatheaded.

Of course it was about trade; the gunships and the armies made sure of
it.

There were I believe never any more than 30,000 British soldiers in India when the
population was around 300 million.

That's a ratio of 1 British soldier to 10,000 Indians. Care to explain how you can
subjugate a population with those numbers ?

Never mind we brought democracy to over 50 nations.

Graham

Indeed, traveling around the world I get impression that British colonies were
handled well. And when left they usually remain in very good relations with
the ex motherland for the mutual benefit and even mostly colonie's benefit.

Belgian colony of DR Congo was another matter, it was the king's personal
property. Plantage slaves not reaching their daily quotas had their arms
chopped off and things like that, millions killed and many more after they were
left to their own devices (which is what they wanted) so they could engage
in a lasting conflict, totaling more dead than any other war after WW2.

Anyone claiming superiority is ridiculous. Put it in perspective, 1000 years is
just a mouse fart. And things change faster than that.

M

 

[TheM]

"Martin Riddle" <martin_rid@verizon.net> wrote in message news:Rvhzk.231$1a2.230@trnddc04...

That's the Li-ion surprise, probably the cell voltages are too low, thus the charger wont charge.
You can try booting into the BIOS and see if there is a Battery learning tool in there, but my guess is that you need a new
battery.
I would go to a larger retailer on the internet, what you want is newly manufactured batteries not old ones. these li-ion
batteries age from the date manufactured, keep them 60-75% charged and they should last for more than 2-3 years. Throw the
battery in the refrigerator next time you store it.

Cheers

And those nutcases think they'll work in a car for 5-10 years...

M

 

[TheM]

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message news:48CDC654.2688CF07@hotmail.com...

John Larkin wrote:
Don't start up that European superiority nonsense again. What it makes
you is fatheaded.

Of course it was about trade; the gunships and the armies made sure of
it.

There were I believe never any more than 30,000 British soldiers in India when the
population was around 300 million.

That's a ratio of 1 British soldier to 10,000 Indians. Care to explain how you can
subjugate a population with those numbers ?

Never mind we brought democracy to over 50 nations.

Graham

Indeed, traveling around the world I get impression that British colonies were
handled well. And when left they usually remain in very good relations with
the ex motherland for the mutual benefit and even mostly colonie's benefit.

Belgian colony of DR Congo was another matter, it was the king's personal
property. Plantage slaves not reaching their daily quotas had their arms
chopped off and things like that, millions killed and many more after they were
left to their own devices (which is what they wanted) so they could engage
in a lasting conflict, totaling more dead than any other war after WW2.

Anyone claiming superiority is ridiculous. Put it in perspective, 1000 years is
just a mouse fart. And things change faster than that.

M

 

[TheM]

"Martin Riddle" <martin_rid@verizon.net> wrote in message news:Rvhzk.231$1a2.230@trnddc04...

That's the Li-ion surprise, probably the cell voltages are too low, thus the charger wont charge.
You can try booting into the BIOS and see if there is a Battery learning tool in there, but my guess is that you need a new
battery.
I would go to a larger retailer on the internet, what you want is newly manufactured batteries not old ones. these li-ion
batteries age from the date manufactured, keep them 60-75% charged and they should last for more than 2-3 years. Throw the
battery in the refrigerator next time you store it.

Cheers

And those nutcases think they'll work in a car for 5-10 years...

M

 

[TheM]

"Eeyore" <rabbitsfriendsandrelations@hotmail.com> wrote in message news:48CDC654.2688CF07@hotmail.com...

John Larkin wrote:
Don't start up that European superiority nonsense again. What it makes
you is fatheaded.

Of course it was about trade; the gunships and the armies made sure of
it.

There were I believe never any more than 30,000 British soldiers in India when the
population was around 300 million.

That's a ratio of 1 British soldier to 10,000 Indians. Care to explain how you can
subjugate a population with those numbers ?

Never mind we brought democracy to over 50 nations.

Graham

Indeed, traveling around the world I get impression that British colonies were
handled well. And when left they usually remain in very good relations with
the ex motherland for the mutual benefit and even mostly colonie's benefit.

Belgian colony of DR Congo was another matter, it was the king's personal
property. Plantage slaves not reaching their daily quotas had their arms
chopped off and things like that, millions killed and many more after they were
left to their own devices (which is what they wanted) so they could engage
in a lasting conflict, totaling more dead than any other war after WW2.

Anyone claiming superiority is ridiculous. Put it in perspective, 1000 years is
just a mouse fart. And things change faster than that.

M

 

[TheM]

"Martin Riddle" <martin_rid@verizon.net> wrote in message news:Rvhzk.231$1a2.230@trnddc04...

That's the Li-ion surprise, probably the cell voltages are too low, thus the charger wont charge.
You can try booting into the BIOS and see if there is a Battery learning tool in there, but my guess is that you need a new
battery.
I would go to a larger retailer on the internet, what you want is newly manufactured batteries not old ones. these li-ion
batteries age from the date manufactured, keep them 60-75% charged and they should last for more than 2-3 years. Throw the
battery in the refrigerator next time you store it.

Cheers

And those nutcases think they'll work in a car for 5-10 years...

M