Chip with simple program for Toy

[Paul E. Schoen]

"petrus bitbyter" <pieterkraltlaatditweg@enditookhccnet.nl> wrote in
message news:48b9b7c0$0$3112$e4fe514c@dreader26.news.xs4all.nl...

The D/A is not that easy.
The most simple solution will be PWM. You'll need a very good low pass
filter to get rid of the sample frequency which in turn will make output
changes slow.
A good and rock-stable way is an R/2R network. You'll need 14 resistors
and 7 output pins to achive 100 (128 to be excact) step resolution. Both
are described in:
http://ww1.microchip.com/downloads/en/AppNotes/00655a.pdf
A more attractive way is using a D/A-convertor. A TC1320 for instance is
a good choice. But the 8-pins chip uses an I2C interface which will be
hard to inplement for a beginner. You can however find example code at
Microchips. For the PIC a PIC12f629 will do.
In all solutions described above you will need an amplifier if you need
an output voltage >5.5V.

I agree with your recommendations, but I found that it is possible to make
a voltage doubler with the PWM output that can be programmed for a range of
about 4 VDC to 6 VDC. It requires only two capacitors, two resistors, and
a diode. It might need to be monitored by one of the ADCs and trimmed, or
if the load is stable, you could make a table of PWM values and output
voltages. The LTspice ASCII for the circuit is at the end. The simulated
outputs with a 10 kHz PWM into a 5 kOhm load after 100 mSec are as follows:

0% 4.07 VDC
5% 4.24 VDC
10% 4.40 VDC
20% 4.72 VDC
30% 5.04 VDC
40% 5.33 VDC
50% 5.62 VDC
60% 5.86 VDC
70% 6.05 VDC
80% 6.09 VDC
85% 5.98 VDC
90% 5.64 VDC

Paul

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

Version 4
SHEET 1 880 680
WIRE -32 16 -64 16
WIRE 160 16 32 16
WIRE 80 80 32 80
WIRE 160 80 160 16
WIRE 160 80 144 80
WIRE 256 80 160 80
WIRE 544 80 336 80
WIRE 608 80 544 80
WIRE 608 128 608 80
WIRE -64 144 -64 16
WIRE 32 144 32 80
WIRE 544 144 544 80
WIRE -64 256 -64 224
WIRE 32 256 32 224
WIRE 32 256 -64 256
WIRE 80 256 32 256
WIRE 544 256 544 208
WIRE 544 256 80 256
WIRE 608 256 608 208
WIRE 608 256 544 256
WIRE 80 304 80 256
FLAG 80 304 0
SYMBOL voltage 32 128 R0
WINDOW 3 13 107 Left 0
WINDOW 123 0 0 Left 0
WINDOW 39 37 52 Left 0
SYMATTR InstName V1
SYMATTR Value PULSE(0 5 100n 100n 100n 80u 100u 2000)
SYMATTR SpiceLine Rser=200
SYMBOL cap 144 64 R90
WINDOW 0 0 32 VBottom 0
WINDOW 3 32 32 VTop 0
SYMATTR InstName C1
SYMATTR Value 1ľ
SYMBOL cap 560 208 R180
WINDOW 0 24 64 Left 0
WINDOW 3 24 8 Left 0
SYMATTR InstName C2
SYMATTR Value 10ľ
SYMBOL schottky -32 32 R270
WINDOW 0 32 32 VTop 0
WINDOW 3 0 32 VBottom 0
SYMATTR InstName D1
SYMATTR Value 1N5818
SYMATTR Description Diode
SYMATTR Type diode
SYMBOL res 592 112 R0
SYMATTR InstName R1
SYMATTR Value 5k
SYMBOL voltage -64 128 R0
WINDOW 123 0 0 Left 0
WINDOW 39 0 0 Left 0
SYMATTR InstName V2
SYMATTR Value 5
SYMBOL res 352 64 R90
WINDOW 0 0 56 VBottom 0
WINDOW 3 32 56 VTop 0
SYMATTR InstName R2
SYMATTR Value 1k
TEXT 118 280 Left 0 !.tran 200m startup

 

[Bob Eld]

"Hammy" <spamme@hotmail.com> wrote in message
news:ihrjb41jjo6t36gerjo2pm785j45jagtfa@4ax.com...

Does anybody know why this would oscillate?

Schematic 5.1V LDO 2Ma - 15Ma

http://i36.tinypic.com/fk78ub.png

According to the bode plot this loop should be stable (85 deg PM, 74
kHz crossover at 20db/decade).

http://i35.tinypic.com/ndwwwk.png

I'm using a 4.7uf ceramic X5R cap (C2) on the output.R11 and C4 place
a zero at 8kHz. I thought it might just be the EA model but I bread
boarded it and yep she's definitely unstable.

Spice transient 2mA to 15mA load step.

http://i37.tinypic.com/2lk2y5x.png

What am I missing?

This circuit has positive feedback with a time constant and far greater than
unity gain. That's how you make oscillators.

How is U7 connected and why is C4, R11 connect from the output to the
non-inverting input of the op-amp.

If this thing didn't oscillate, there would be something wrong.

 

[Rod Speed]

John Fields <jfields@austininstruments.com> wrote

Rod Speed <rod.speed.aaa@gmail.com> wrote

John's original, still right at the top, is just plain wrong
on WHEN that collection of silly senile old farts realised
that the earth does in fact revolved around the sun.

Sorry for the confusion.

There is no confusion and there still isnt. You were and still are just plain wrong.

What I was referring to was the Roman Catholic Church's
official admission that Geocentrism was wrong

Yes, that was always clear.

and, AIUI, that acknowledgement only occurred a few years ago.

And that is where you were always just plain wrong. It happened a LONG time before that.

Like I said, what actually happened only a few years ago, was that
they did officially admit that Galileo had been very badly treated.

Small comfort for Galileo, who knew he was right, beyond a shadow of doubt,

And he wasnt alone in recognising that at that time. The evidence was very clear.

but was forced to perjure himself

He didnt even perjure himself.

in order to not be killed by the Nazis of that time.

You wouldnt know what a real Nazi was if one bit you on your lard arse.

And you, "Rod Speed", what do you have to offer?

Never ever could bullshit its way out of a wet paper bag.

 

[Paul E. Schoen]

"Randy Day" <randy.day@shaw.cax> wrote in message
news:MPG.2323a04deca2783b989681@shawnews.ss.shawcable.net...

I downloaded some stuff on how to use
USB from:

http://pe.ece.olin.edu/ece/projects.html

I want to make a PIC act as an HID
keyboard, but I've come up with a couple
questions before I get too deep into this.

1) Most of the schematics I see show an
external xtal running the clock; is this
necessary. or is the onboard clock
adequate for short data xfers?

USB clocks need to be very accurate, so the external crystals are the way
to go.

2) Prof. Minch's code simply keeps sending
the same text over and over. What's the
simplest way to have the computer send a
char to the PIC saying 'OK, send me the
next batch!'.

Thanks. This stuff is like trying to
swallow an elephant!

I got a USB development kit from Microchip that can be configured as a
keyboard, mouse, game port, or a USB to Serial converter. They have pretty
good tutorials, but I attended an introductory class on USB when I went to
their MASTERs conference a few years ago, and then I went to another local
full-day training class that helped me understand a bit more.

The microchip forums are also good resources for USB questions, if you are
using Microchip products such as the PIC18F4550.

You might check the Microchip website for a training class in USB From
Scratch (390 USB). There are some coming up soon in Cleveland, Boston, and
LA.

Another good USB resource is www.beyondlogic.org.


Paul

 

[Andrew Holme]

"Hammy" <spamme@hotmail.com> wrote in message
news:sjtkb49lroa1cvdfrtfk7cbqqsfhnb9qh8@4ax.com...

On Sat, 30 Aug 2008 18:33:48 -0700, "Bob Eld" <nsmontassoc@yahoo.com
wrote:


This circuit has positive feedback with a time constant and far greater
than
unity gain. That's how you make oscillators.

How is U7 connected and why is C4, R11 connect from the output to the
non-inverting input of the op-amp.

If this thing didn't oscillate, there would be something wrong.

I'm following the example here.

Basic P-MOS LDO. Ask The Applications Engineer-37

http://i38.tinypic.com/1o64hz.png

I'm following this Appnote from National for using a ceramic cap. They
have an NPN output driving the pass PNP. Would you recommend this.

http://i35.tinypic.com/4t33uq.png

AN-1482 LDO Regulator Stability Using Ceramic Output Capacitors

http://www.national.com/an/AN/AN-1482.pdf

The regulator is stable with 20mV ripple when I use two 2.2uf Tant
caps with 1.75 ohms esr. And a small integrator cap from the positive
terminal to output and a small cap across the top of the divider.

I thought I would try to use one 805 ceramic mainly for it's small
size.

The P-mosfet (U7) is connected source to input drain to output gate to
MCP6002 output through a 10 ohm R.It is on a breadboard with some long
leads.

Could you reccomend any other application notes or material that goes
in more detail on stabilizing LDO's with ceramic output caps.

Thanks

The Rcomp and Ccomp feedback needs to be negative i.e. it needs to go to the
inverting input. This means you need a resistor in series with the Vref, or
you add an NPN output transistor with suitable collector resistor to
discharge the PMOS gate.

 

[petrus bitbyter]

"Paul E. Schoen" <pstech@smart.net> schreef in bericht
news:48b9f098$0$31984$ecde5a14@news.coretel.net...

"petrus bitbyter" <pieterkraltlaatditweg@enditookhccnet.nl> wrote in
message news:48b9b7c0$0$3112$e4fe514c@dreader26.news.xs4all.nl...

The D/A is not that easy.
The most simple solution will be PWM. You'll need a very good low pass
filter to get rid of the sample frequency which in turn will make output
changes slow.
A good and rock-stable way is an R/2R network. You'll need 14 resistors
and 7 output pins to achive 100 (128 to be excact) step resolution. Both
are described in:
http://ww1.microchip.com/downloads/en/AppNotes/00655a.pdf
A more attractive way is using a D/A-convertor. A TC1320 for instance is
a good choice. But the 8-pins chip uses an I2C interface which will be
hard to inplement for a beginner. You can however find example code at
Microchips. For the PIC a PIC12f629 will do.
In all solutions described above you will need an amplifier if you need
an output voltage >5.5V.

I agree with your recommendations, but I found that it is possible to make
a voltage doubler with the PWM output that can be programmed for a range
of
about 4 VDC to 6 VDC. It requires only two capacitors, two resistors, and
a diode. It might need to be monitored by one of the ADCs and trimmed, or
if the load is stable, you could make a table of PWM values and output
voltages. The LTspice ASCII for the circuit is at the end. The simulated
outputs with a 10 kHz PWM into a 5 kOhm load after 100 mSec are as
follows:

<snip spice list>

Think this comes very close to the OPs requirements. It'll be a challenge to
keep the voltage stable while measuring the frequency but even a 12F629 has
two timers available so it wil not be that hard. There's no need to drive a
PIC to its limits by using 5.5V power. Ordinary stabilized 5V will do. Where
did you got this idea from?

petrus bitbyter

 

[Bob Eld]

"Hammy" <spamme@hotmail.com> wrote in message
news:sjtkb49lroa1cvdfrtfk7cbqqsfhnb9qh8@4ax.com...

On Sat, 30 Aug 2008 18:33:48 -0700, "Bob Eld" <nsmontassoc@yahoo.com
wrote:


This circuit has positive feedback with a time constant and far greater
than
unity gain. That's how you make oscillators.

How is U7 connected and why is C4, R11 connect from the output to the
non-inverting input of the op-amp.

If this thing didn't oscillate, there would be something wrong.

I'm following the example here.

Basic P-MOS LDO. Ask The Applications Engineer-37

http://i38.tinypic.com/1o64hz.png

I'm following this Appnote from National for using a ceramic cap. They
have an NPN output driving the pass PNP. Would you recommend this.

http://i35.tinypic.com/4t33uq.png

AN-1482 LDO Regulator Stability Using Ceramic Output Capacitors

http://www.national.com/an/AN/AN-1482.pdf

The regulator is stable with 20mV ripple when I use two 2.2uf Tant
caps with 1.75 ohms esr. And a small integrator cap from the positive
terminal to output and a small cap across the top of the divider.

I thought I would try to use one 805 ceramic mainly for it's small
size.

The P-mosfet (U7) is connected source to input drain to output gate to
MCP6002 output through a 10 ohm R.It is on a breadboard with some long
leads.

Could you reccomend any other application notes or material that goes
in more detail on stabilizing LDO's with ceramic output caps.

Thanks

Note that in the above circuits that the overall feedback is negative and
that the compensation is also negative feedback around the internal op-amp
to the inverting input.

I think that is right, it looks like U7 is connected source to the positive
voltage source and the drain to the output. That makes sense from a voltage
drop point of view but it does add an inversion in the signal path.

That additional inversion causes confusion about which input is inverting
and which is noninverting on the op-amp. Overall, the + and - switch but
locally around the amp, they don't. In other words, the compensation is
simply to the wrong input pin on the amp.

In general circuits with emitter or source follower outputs perform better
than collector or drain outputs because the output impedance is lower even
without feedback and no additional voltage gain is added to an already very
high gain op-amp circuit.

All gain stages add an additional pole to the frequency response. Op-amps
normally have two internal gain stages giving a two pole response with a
maximum phase shift of 180 deg. When you add a third gain stage, you
automatically add an addional phase shift ultimately to 270 degrees at the
highest frequencies. You also give more total gain to deal with.

This makes compensation more difficult and adds concerns with overshoot,
undershoot, rise time, and poor damping. I suspect that even if you get the
circuit to work ok in the steady state, that it will have poor transient
response and be unable to quickly and accurately respond to changes line and
load conditions.

 

[Andrew Holme]

"Hammy" <spamme@hotmail.com> wrote in message
newsb8lb415evq9fevi4uh4v4cfmhljq4s55p@4ax.com...

On Sun, 31 Aug 2008 12:48:47 +0100, "Andrew Holme" <ah@nospam.co.uk
wrote:

The Rcomp and Ccomp feedback needs to be negative i.e. it needs to go to
the
inverting input. This means you need a resistor in series with the Vref,
or
you add an NPN output transistor with suitable collector resistor to
discharge the PMOS gate.



Yes thank you I think that does it

I'm not sure I'm calculating the gain required for a desired crossover
frequency correctly. For example this is the open loop Bode plot of
the regulator (uncompensated).

http://i35.tinypic.com/4g2qkg.png

From this I read a crossover Frequency of 20 kHz and a PM of 14.267.
if I wanted a crossover at say 100kHz the bode plot says I need to
provide 26dB (19.953) of gain.

New schematic with compensation components.

http://i36.tinypic.com/1qk8sx.png

R3= 1k

So for a gain of 19.953

R4= R3 x 19.953
=19.953k ohms

To place a zero Fz at say 6kHz.

C4= 1/R4xFz
= 1/R4x 6Khz
=8.353nf

According to this bode plot:

http://i35.tinypic.com/2my6tms.png

The calculated components give a crossover frequency at 6.5341kHz,PM
of 79.619.What am I doing wrong?

For one thing, you're missing a factor of 2*PI. You must use angular
frequency w = 2*PI*f = 1/R/C

Another thing is you calculated the required gain BEFORE you inserted the
zero. The Bode plot is different after you add the zero so you need to
iterate!

Are you including the transconductance of the PMOS and the load resistance
R10 and the R1/R2 voltage divider in your loop gain equation? Just
checking.

 

[stan]

BretCahill@peoplepc.com wrote:

Of course, your idea of "intelligent participation" and
"flaming" might be quite different from mine, or someone else. ?I
don't think there's any real formula here.

There may be an issue as to what is on topic for a group but the OP
and end of branch posting profile are purely objective.

I'm curious. This is the first indication I've seen that you have any
awareness of appropriate behavior on usenet. Are you saying that you are
aware and understand that different newsgroups exist to discuss
different topic and that crossposting is rude and unwanted?

Google could easily provide baseball style stats for each poster,

1. The number of OPs.

2. The number of OPs/response postings.

3. The number of responses/OP.

4. The average number of different posters/OP.

5. The above stats over time, a graph to show improvement.

Someone suggest the above to Google.

We could call it the troll index.

 

[stan]

BretCahill@peoplepc.com wrote:

Just google the name.

Is the name always found in the OP of many controversial / popular
threads?

This indicates an active mind.

Or a confused and simple mind, limited by obstinance.

Or is the name always flaming out at the ends of branchs?

If the poster isn't really interested in technology, or fancies it as
something other than what it really is, then he'll always wind up
saying something stupid and, after it's pointed out how stupid it was,
he'll flame out at the end of a branch.

Even more, anyone who is posting to a tech group but isn't really
interested in technology is irrational *per se.*

I think the easiest way to identify someone posing as qualified is to
check the number of crossposted groups. The more groups the more
confusion; the metric simply never fails.

 

[Rod Speed]

BretCahill@peoplepc.com wrote:

Google already gives out posting activity of posters on news groups,
the total number of posts over a certain period of time.

This could be supplemented with other difficult to compile but public
stats and search information.

The number of OP posts as well as the number of OP/total posts ratio,
for example.

The average number of responses and number of different names received
by a poster's OP posts.

The number of BE (branch endings) as well ast the BE/total posts.

A search box could be included to pull up all of a poster's OP posts,
and all the posts in a selected group to show the OP posts are on
topic.

A search box could be included to pull up all a poster's BE posts to
see if the the branch ended because the poster won a debate or flamed
out.

If a poster is flaming out in 95% of his posts then everyone will be
able to quickly see he has nothing to contribute to a tech discussion.

Harder to quantify the silly little children who do nothing like
puerile coat trailings and who get the response those deserve tho.

 

[Rod Speed]

BretCahill@peoplepc.com wrote

Just google the name.

Doesnt help with those who use lots of nyms.

All the nyms of a single person will fit the same profile

Wrong, as always.

which will out those using nyms.

Only in your pathetic little pig ignorant drug crazed fantasyland.

Is the name always found in the OP of many controversial / popular threads?

This indicates an active mind.

Nope, just a pathetic excuse for a troll/complete raving loony most of the time.

Then let's out these trolls and raving loonies by encouraging to Google
to compile and publish OP/branch stats on each poster's profile.

No point, its obvious who those are.

Everyone would know the number of your OPs, your OPs/total
posting ratio, the number of times you flame out at the end a
branch, number of branch endings/total postings, etc.

It aint just the number that matter. So do choose to let the air
out of the silliest posts and it isnt feasible for groups.google to
work out which are the silliest posts that deserve to be flamed.

Or even which is the spam either.

<reams of your puerile coat trailing flushed where it belongs>

Or is the name always flaming out at the ends of branchs?

The most that can indicate is a short fuse/doesnt tolerate fools/trolls.

Has flaming out at the end of a branch ever shut up any fools or trolls?

Yep, that does work with plenty of them.

Trying something over and over that doesn't work is the definition of insanity.

Nope.

<reams of your puerile coat trailing flushed where it belongs>

If the poster isn't really interested in technology, or fancies
it as something other than what it really is, then he'll always
wind up saying something stupid and, after it's pointed out
how stupid it was, he'll flame out at the end of a branch.

FAR more often its just whats inevitable with any discussion, no
one changes their original position and the style of the ending has
a lot more to do with the nature of usenet than anything else.

Mostly they just dodge / change the issue.

Thread drift is endemic with any viable discussion.

That's why the issue must be raised again in a new OP.

The puerile coat trail, actually.

Even more, anyone who is posting to a tech group but
isn't really interested in technology is irrational *per se.*

Wrong again. Some arent interested in the tech but are interested in discussing other things

Then why aren't they discussing those "other things" on other groups?

Because the other groups have fuck all participating in them.

If there is no other group for their "issue" then why don't they start one?

Because hardly anyone will even notice that they have done that.

And hordes of very narrowly focussed groups works very badly indeed.

 

[Rod Speed]

Bret Cahill <BretCahill@aol.com> wrote:

Is the name always found in the OP of many controversial / popular
threads? This indicates an active mind.

Nope,

If no one started any threads, you wouldn't be able to type,

Wrong again. I'd be able to do that in any thread, not just those that have just been started, stupid.

 

[Rod Speed]

BretCahill@peoplepc.com wrote:

They didn't give a driving profile but if that claim held for the
open highway, that would be $100/day for a 600 mile day, $180 for a
1000 mile day and even without the green write offs the savings
would more than make the tractor payments.

In town the savings of a hybrid could be great but not so much on
the highway.

30-40% savings sounds very high for an average truck journey.

Not gonna happen on the highway, not even with full series which would
only work on flat land anyway.

But the hybrid tractor, series or parallel, will prevail if only
because sooner or later trains will electrify and a lot or most long
haul trucking will disappear.

Trucking will eventually consist of a lots of short trips to the rail
yard.

That wont happen, because transport fuels are perfectly viable.

 

[Rod Speed]

BretCahill@peoplepc.com wrote:

They didn't give a driving profile but if that claim held for the
open highway, that would be $100/day for a 600 mile day, $180 for a
1000 mile day and even without the green write offs the savings
would more than make the tractor payments.

In town the savings of a hybrid could be great but not so much on
the highway.


? ? ? The link qwerty provided talked about short run delivery trucks
and bucket trucks like the utility companies use. ?Nothing about the
OTR trucks unless I missed it.

Hybridization is a minor advantage on the highway. An old diesel
Rabbit gets slightly less mpg as a new Prius on the highway.

What matters is what the best diesels get, and its better than a new Prius on the highway.

Nevertheless, if it becomes politically correct to go up a 6% grade at < 8 mph,

Thats never going to happen.

a full series hybid truck may appear.

Nope, because it wont and biodiesel will be used instead.

On the down hill the energy could be regenerated to recharge the
battery instead of overheating the brakes. But right now a series
hybrid truck would require a multi ton battery to get 80,000 lbs over a
mountain at what is currently considered an acceptable speed ~ 35 mph.

Still would even with <8mph.

Maybe series hybridization would make some sense on OTR routes
restricted to the midwest or below the Southern Crescent, N.O. - DC.
Instead of a 400 hp diesel running well below its "sweet spot" a tweaked
100 hp engine might use 10 -15% less fuel in a full series hybrid.

We'll use biodiesel or CNG/LPG instead.

In any event trains will pick up a lot of long haul

Bet they dont with the sort of stuff moved by trucks.

which should increase demand for hybrid truck tractors on
short haul to the rail yard. Peterbilt made a smart move.

Nope. Bet its a flop and anyone with a clue uses biodiesel or CNG/LPG instead.

One of the web pages claimed that the Peterbilt drive
train could run on batteries only for limited periods of time.

Just because some fool claims it doesnt make it gospel.

The battery farm tractor drive train is already in production.

Any conventional farm tractor can run on diodiesel with no modification.

We just need a way to recharge it, either by partial trolly or battery exchange.

Makes a lot more sense to use biodiesel instead.

It seems like there are a growing number of trucks running about 63 mph.

The big trucking companies changed all the governors on
their fleets to save fuel. If you see a company semi going
over 62, it's because it is going downhill without brakes.

Just another of your pathetic little drug crazed pig ignorant fantasys.

even on I-80 here in Nebraska. The speed limit is 75.

In CA the speed is 55 for trucks

More fool CA.

but supposedly CHP won't ticket below 63.

That's why all the governors are set at 62.

So they clearly arent set to save fuel, stupid.

A few trucks I've seen have a single wheel instead of duals
on the trailers. I guess the fuel saving is something like 2%.

You mean single axle or single tire?

Wheel/tire.

Single axle might be cost effective for low weight loads as DOT limits the weight/axle.

Single tire might not be an efficiency issue. It's just that it can be hauled between furrows.

Thanks for that completely superfluous proof that you have never ever had a fucking clue.

Only a minority of crops even have furrows.

 

[Rod Speed]

John Fields <jfields@austininstruments.com> wrote

Rod Speed <rod.speed.aaa@gmail.com> wrote
John Fields <jfields@austininstruments.com> wrote
Rod Speed <rod.speed.aaa@gmail.com> wrote

John's original, still right at the top, is just plain wrong
on WHEN that collection of silly senile old farts realised
that the earth does in fact revolved around the sun.

Sorry for the confusion.

There is no confusion and there still isnt. You were and still are just plain wrong.

OK, then, instead of your bluster, let's see your evidence.

YOU made the original stupid claim.

YOU get to provide the evidence.

THATS how it works.

What I was referring to was the Roman Catholic Church's
official admission that Geocentrism was wrong

Yes, that was always clear.

and, AIUI, that acknowledgement only occurred a few years ago.

And that is where you were always just plain wrong. It happened a LONG time before that.

OK, then, instead of your bluster, let's see your evidence.

YOU made the original stupid claim.

YOU get to provide the evidence.

THATS how it works.

Like I said, what actually happened only a few years ago, was that
they did officially admit that Galileo had been very badly treated.

OK, then, instead of your bluster, let's see your evidence.

YOU made the original stupid claim.

YOU get to provide the evidence.

THATS how it works.

Small comfort for Galileo, who knew he was right, beyond a shadow of doubt,

And he wasnt alone in recognising that at that time. The evidence was very clear.

That's not the point.

Corse it is.

but was forced to perjure himself

He didnt even perjure himself.

In order to save his life, he was forced to lie about his
beliefs before a legislating body, which is perjury.

Wrong, as always.

<reams of your puerile shit flushed where it belongs>

 

[stan]

Bret Cahill wrote:

Of course, your idea of "intelligent participation" and
"flaming" might be quite different from mine, or someone else. ?I
don't think there's any real formula here.

There may be an issue as to what is on topic for a group but the OP
and end of branch posting profile are purely objective.

I'm curious.

That's only because you don't know me. If you had the stats on me you
would either go to other threads ("this Cahill loser does nothing but
flame out at the ends of branches and everyone knows it") or if you
_did_ post to my threads you'ld spend less time flaming and more time
making a contribution to the debate.

Under what definition do you consider this a debate?

This is the first indication I've seen that you have any
awareness of appropriate behavior on usenet.

Who decides what is appropriate behaviour?

Clearly you don't care, so why do you ask?

<snip>

Who decides if and what crossposting is bad?

Again, why do you ask?

Instead of debating all these subjective issues it is much better to
just give out the stats and profiles of posters, maybe a cross posting
index as well. Mine might be high but my philosophy is
multidisciplinarity solves problems.

Do you understand the concepts of interest and efficiency ? What
problems have you solved? Hasn't your trolling created problems?

I'd be happy for everyone to know I often cross post.

I still wonder if you ever DON'T crosspost. How about it, have you ever
not crossposted?

Google could easily provide baseball style stats for each poster,

1. ?The number of OPs.
2. ?The number of OPs/response postings.
3. ?The number of responses/OP.
4. ?The average number of different posters/OP.
5. ?The above stats over time, a graph to show improvement.

Someone suggest the above to Google.
We could call it the troll index.

Maybe have some hands off automatic kill file for those with the
"wrong" stats.

Now we agree. I sent google a suggestion that they kill trolls at the
source. Simply not allow crossposting through their often abused portal.

Right now a lot of thin skinned types are kill filing posters merely
because they couldn't take the truth.

Sort of seems like a real lack of imagination and intelligence to be
unable to come up with other possibilities for not wanting to waste time
on off topic posts. To be that limited it must be difficult.

Life is short, consequently time is precious. The immature and boorish
behavior of trolls is an unacceptable time sink that should be mostly
avoided.

I'll offer an observation. Those with the least to say are often the
loudest, most prolific, and most persistent. I can only guess but I
think they must be driven by a need for attention. I'm truly glad most
people grow out of that childhood phase.

 

[stan]

Rod Speed wrote:
<snip>

Trying something over and over that doesn't work is the definition of insanity.

Nope.

Now here you have some credibility. What is the correct definition?

<snip>

Because the other groups have fuck all participating in them.

Could that be lack of interest?

If there is no other group for their "issue" then why don't they start one?

Because hardly anyone will even notice that they have done that.

And hordes of very narrowly focussed groups works very badly indeed.

I read several groups you aren't disturbing and they work quite well. I
guess you can't see any groups you don't disturb so you will never see
how well they can work. That's truly sad.

 

[Bob Eld]

"Hammy" <spamme@hotmail.com> wrote in message
news:4iolb4t28j2jaoopme2u6u7lk5sgou1hsk@4ax.com...

On Sun, 31 Aug 2008 07:55:21 -0700, "Bob Eld" <nsmontassoc@yahoo.com
wrote:


Note that in the above circuits that the overall feedback is negative and
that the compensation is also negative feedback around the internal
op-amp
to the inverting input.

I think that is right, it looks like U7 is connected source to the
positive
voltage source and the drain to the output. That makes sense from a
voltage
drop point of view but it does add an inversion in the signal path.

That additional inversion causes confusion about which input is inverting
and which is noninverting on the op-amp. Overall, the + and - switch but
locally around the amp, they don't. In other words, the compensation is
simply to the wrong input pin on the amp.

In general circuits with emitter or source follower outputs perform
better
than collector or drain outputs because the output impedance is lower
even
without feedback and no additional voltage gain is added to an already
very
high gain op-amp circuit.

All gain stages add an additional pole to the frequency response. Op-amps
normally have two internal gain stages giving a two pole response with a
maximum phase shift of 180 deg. When you add a third gain stage, you
automatically add an addional phase shift ultimately to 270 degrees at
the
highest frequencies. You also give more total gain to deal with.

This makes compensation more difficult and adds concerns with overshoot,
undershoot, rise time, and poor damping. I suspect that even if you get
the
circuit to work ok in the steady state, that it will have poor transient
response and be unable to quickly and accurately respond to changes line
and
load conditions.


Well after a bit of experimentation this gives me 32kHz BW,PM of 50.

http://i33.tinypic.com/2afegbb.png

Simulated transient response. This is the worst case load for it 38kHz
10% duty. 2mA to 15mA load step.

http://i34.tinypic.com/2u9mqkl.png

This is the actual measured ripple with worst case load.I'm pretty
sure that those narrow spikes are inductive from all the long leads on
my breadboard.

http://i38.tinypic.com/2zjhny0.jpg

At least I have something to work with I can play with it some more
once I do a layout. CH2 BLUE is the output ripple 20mV division. CH1
is the gate pulses to a FET for a pulsed load.

Thanks for your help everyone any further advice is welcome

The "ripple" pic, http://i34.tinypic.com/2u9mqkl.png doesn't look right to
me. If I read the time axis right (big if) it looks like it is oscillating
at about 30kHz. I doubt that has anything to do with lead inductance. If
true, I suspect amplifier stability is questionable for the reasons I
mentioned above. It is ALWAYS troublesome to add another gain stage to an
op-amp as that circuit does because of the increased loop gain and
accumulating phase shift.

 

[Rod Speed]

stan <smoore@exis.net> wrote

Rod Speed wrote

Trying something over and over that doesn't work is the definition of insanity.

Nope.

Now here you have some credibility.

Unlike you.

What is the correct definition?

There is no nice tidy definition thats anything like as simple as that.

Even more, anyone who is posting to a tech group but
isn't really interested in technology is irrational *per se.*

Wrong again. Some arent interested in the tech but are interested in discussing other things

Then why aren't they discussing those "other things" on other groups?

Because the other groups have fuck all participating in them.

Could that be lack of interest?

Its more that usenet has always had a real tendency to collect groups of individuals
in particular newsgroups where the newsgroup name only quite losely describes
their general interests and a lot more than that does get discussed.

And there are always a few obsessively anal that hate that too.

If there is no other group for their "issue" then why don't they start one?

Because hardly anyone will even notice that they have done that.

And hordes of very narrowly focussed groups works very badly indeed.

I read several groups you aren't disturbing and they work quite well.

Irrelevant to what was being discussed there.

I guess you can't see any groups you don't disturb so you will never see how well they can work.

Guess again. They do tend to get crossposted ocassionally.

That's truly sad.

Thats truly pathetic, as always with you.