How inaccurate is a 555 or 7555 REALLY?

[[email protected]]

Of course I knew how. But the resistors I would have had to use were
0.6" long and 0.2" wide on the board, so it would have wasted space,
not to mention confusing the final test technicians and the service
engineers.

---
You seem to be gravitating toward the "use a PIC" mentality when,
for the OP's purpose, suggesting that he use anything he'd have to
learn to program would be ridiculous. But that's never stopped you
before, huh?
---

A PIC may be programmable, but it isn't programmable logic, and can't
do a lot of things that are easy in programmable logic.

Programming programmable logic can be handled through a variety of
interfaces, depending on the manufacturers programming software
(usually available free for everything except bleeding-edge new parts,
which the Xilinx CoolRunner isn't - Xilinx bought it from Philips).

Most of the ones I've run across have included a graphical option,
which makes the process similar to hooking up logic gates and
bistables.

I prefer to write out a seres of logic equations.

I didn't find any of these approaches difficult to learn - nothing
remotely as difficult as mastering a computer language, where it took
me a week to learn Fortran 4, and nearly a year before I could produce
a well formatted page of output (including printed graphs). The MACRO-8
assembly language for the PDP-8 was much easier - mainly because the
teletype output made more sense.

There is a certain learning curve in learning how to use Boolean logic,
and you need extra time learn how to hook up CMOS parts to realise that
logic - most people would be better off putting the exra time into
learning how to program programmable logic.

The choice of which programmable part should probably be referred to
comp.arch.fpga, but one thing is for sure - you will be able get all
the logic into a single modern PLD.

 

[[email protected]]

Jim Thompson wrote:

On Tue, 05 Dec 2006 04:00:07 GMT, Robert Baer


Jim Thompson wrote:


On Mon, 04 Dec 2006 05:27:34 GMT, Robert Baer



Jim Thompson wrote:



On Mon, 04 Dec 2006 00:03:56 GMT, Robert Baer




Jim Thompson wrote:



On Sun, 03 Dec 2006 19:19:05 GMT, Robert Baer


[snip]


That ratio is temperature sensitive...


What "ratio" is that?

...Jim Thompson

The ratio of the ersistor calues in the (comparitor) divider.


What makes you think resistor ratios have a TC?

Solid ratios is the only reason we can build analog IC's at all.

...Jim Thompson

I suggest that you do some measuring...


I suggest you get you head out of your ass. I've been designing IC's
since the beginning of time... ratiometric is what it's all about.

...Jim Thompson

Do tell; that is ASS-u-ME-ing that the ratios are *constant*.


Who do you think you are, Eeyore or some similarly IGNORANT person?

Please explain on me how the ratios are not. (Assuming you have even
the vaguest clue about resistor TYPES.)

...Jim Thompson
Sounds like you may need an education in electronics...

Just like a Usenet IDIOT to mouth off like an ass instead of giving
the explanation.

I know this really must be a BEAR for you to cope with, but he is
right.

WHO is it you think is right, me or Baer? I can't tell from your
attributions.

Neither. He's being rude to Baer for being wrong, and rude to you for
mouthing off like an ass instead of giving a comprehensible explanation
- preferrably one that covers the fact that the area ratios actually
acheived on an integrated circuit include a manufacturing tolerance.

 

[JoeBloe]

Jim Thompson wrote:

On Tue, 05 Dec 2006 04:00:07 GMT, Robert Baer


Jim Thompson wrote:


On Mon, 04 Dec 2006 05:27:34 GMT, Robert Baer



Jim Thompson wrote:



On Mon, 04 Dec 2006 00:03:56 GMT, Robert Baer




Jim Thompson wrote:



On Sun, 03 Dec 2006 19:19:05 GMT, Robert Baer


[snip]


That ratio is temperature sensitive...


What "ratio" is that?

...Jim Thompson

The ratio of the ersistor calues in the (comparitor) divider.


What makes you think resistor ratios have a TC?

Solid ratios is the only reason we can build analog IC's at all.

...Jim Thompson

I suggest that you do some measuring...


I suggest you get you head out of your ass. I've been designing IC's
since the beginning of time... ratiometric is what it's all about.

...Jim Thompson

Do tell; that is ASS-u-ME-ing that the ratios are *constant*.


Who do you think you are, Eeyore or some similarly IGNORANT person?

Please explain on me how the ratios are not. (Assuming you have even
the vaguest clue about resistor TYPES.)

...Jim Thompson
Sounds like you may need an education in electronics...

Just like a Usenet IDIOT to mouth off like an ass instead of giving
the explanation.

I know this really must be a BEAR for you to cope with, but he is
right.

WHO is it you think is right, me or Baer? I can't tell from your
attributions.

He was the one that wouldn't give the explanation you asked for.
Must be a BEAR for him. :-]

 

[John Fields]

Of course I knew how. But the resistors I would have had to use were
0.6" long and 0.2" wide on the board, so it would have wasted space,

---
Really?

ISTR that 1/8 watt resistors and 1N914s were available back then, so
the entire decoder would have used up the same real estate as an 8
pin DIP, as well as not using nearly the amount of power the TTL
glue you'd have to otherwise make the decoder from would.

 

[[email protected]]

---
Really?

ISTR that 1/8 watt resistors and 1N914s were available back then, so
the entire decoder would have used up the same real estate as an 8
pin DIP, as well as not using nearly the amount of power the TTL
glue you'd have to otherwise make the decoder from would.
---

1N914s weren't a problem, but company policy had fixed on one style of
600mW Philips metal film resistor, and 1/8 watt resistors weren't an
option.

Of course. Unconfusing them takes time ande costs money. All other
things being more or less equal, I'll go for the transparent design
every time.
So you don't use programmable logic parts. Why am I not surprised.

The glue logic approach was the appropriate way to solve the OP's
problem. End of story.

If you say so John. But you do look a bit silly, bent over, with your
head buried in the sand.

 

[John Fields]

1N914s weren't a problem, but company policy had fixed on one style of
600mW Philips metal film resistor, and 1/8 watt resistors weren't an
option.

---
Still, you could have mounted it Jap style.

Oh, well...
---

Of course. Unconfusing them takes time ande costs money. All other
things being more or less equal, I'll go for the transparent design
every time.

---
So you're a proponent of recurrent production costs in lieu of
proper training? How much money do you think you've "saved" over
the years by doing it that way?
---

So you don't use programmable logic parts. Why am I not surprised.

---
I don't know, but you seem to be trying to build up this big case
where it's evil _not_ to use PLDs. For me it's not a big deal since
I usually only have a little glue logic surrounding a
microcontroller and the expense and bother of the PLD isn't worth it
when I can use good ol' 74HC and 4000 parts from _anywhere_ to get
the job done. Cheap, too!
---

 

[[email protected]]

---
With a total of 6520 posts under your belt, I'd be willing to bet
that at least one third of them contain slurs of one kind or
another, consciously or unconsciously made since you just can't seem
to help yourself.
---

So quote a few. With 2173 to chose from, even you should be able to
come up with a few examples.


I don't. I simply haven't seen much about RISC or DSP parts in the
stuff you post,or anythihg about programmable logic, for that matter.

Quite a lot. Try doing the system design for an electron beam
microfabricator sometime, or a stroboscopic electron microscope. Not a
place for a 555-addict.

 

[John Fields]

---
I don't know, but you seem to be trying to build up this big case
where it's evil _not_ to use PLDs. For me it's not a big deal since
I usually only have a little glue logic surrounding a
microcontroller and the expense and bother of the PLD isn't worth it
when I can use good ol' 74HC and 4000 parts from _anywhere_ to get
the job done. Cheap, too!
---

---
Forgot to mention...

This is USENET, Bill, and if you think anyone's going to be
interested in learning PLD when what they really want is a one-off
they can wire up themselves and get working with the least amount of
hassle, then you're just fucking insane.

Also, I just went over to the Xilinx site and looked up prices on
their Cool-Runner stuff.

Pick me up off the floor, OK?

I'm laughing so hysterically it's all I can do to type this without
meaking missteaks!

 

[John Fields]

So quote a few. With 2173 to chose from, even you should be able to
come up with a few examples.

---
Nope. I'm the one willing to bet, so you're the one that has to
prove me wrong.

So, show me 4347 posts that don't contain some vitriol.
---

I don't. I simply haven't seen much about RISC or DSP parts in the
stuff you post,or anythihg about programmable logic, for that matter.

---
That's because I choose not to use it.

What you've seen me post is circuits that are appropriate for USENET
querants who want something simple they can build themselves and
have a fair chance of getting them to work. That doesn't include
DSP, PLD, or RISC because that's not what they want.
---

Quite a lot. Try doing the system design for an electron beam
microfabricator sometime,

---
I'll see your electron beam microfabricator and raise you the system
_and_ circuit design for an interferometer driven laser
photolithographic pattern generator.
---

or a stroboscopic electron microscope.

---
That doesn't sound like such a big deal. What? a couple of
detectors instead of just one, maybe two beams?
Steering magnetics? Duck soup!
---

Not a place for a 555-addict.

---
You sure do seem to harp a lot on that anti-555 crap.

Too bad you were never successful in using it in any of your
designs, (even though it's very easy to use) since if you had been
you might actually appreciate Camendzind's genius. If nothing else,
I think the use of the ratiometric voltage divider in order to
largely eliminate variations in output timing WRT supply voltage and
temperature variations was brilliant, as was the window detector
placed at the 1/3Vcc and 2/3Vcc taps of the divider.

YMMV, but I think you kind of begrudge him his success because you
think you're ever so much smarter than he is and yet...

 

[[email protected]]

Don't be silly. First you libel me, then you claim it is up to me to
prove that your unsupported libel is false.

---
I'll see your electron beam microfabricator and raise you the system
_and_ circuit design for an interferometer driven laser
photolithographic pattern generator.
---

You haven't raised the stakes at all - the electron beam
microfabricator included a laser driven inteferometric stage
positioning system, and hardware to map arbitrarily scaled data
defining the inegrated circuit masks to be written onto the
interoferometer measurements. We did fall short of full generality by
assuming that the wafer/mask to be written was within two degrees of
being square to the interferometer designed grid, but our customers
assured us that that was all the tolerance we needed.

Our electron beam provided better resolution than your
photolithographuc system ever could, and was doing write on the fly. I
think you have just een comprehensively trumped.

---
That doesn't sound like such a big deal. What? a couple of
detectors instead of just one, maybe two beams?
Steering magnetics? Duck soup!
---

Not if you want 0.5nsec wide stroboscopic pulses (which required an
electrostatic beam-blanking system - albeit the boss would not spring
for the wide-voltage range version on which I'm named as the inventor.
Magnetic beam blanking is nice - we used it on the old EBMF 10.5
electron microfabricator - but it won't go sub-nanosecond nor anywhere
near it.

In fact the interesting part of that system, which I first proposed in
1983 (too late to have qualified for a patent) was the "multiple flash
per cycle" feature. We could keep track of up to 1024 phase points, and
build up our waveform/image at the 25MHz sampling rate of the system
(it should have been faster, but we started off with an unrealistic
completion date which created a lot of problems) rather than the repeat
cycle of the process we were following.

And we didn't need two detectors - a sing;e relatively fast
Everhart-Thornley detector above the final lens did everything we
needed. The fast-focussed photo-multiplier tube did need a fast output
amplifier, which incorporated an analog finite-impulse response filter
built around a lumped constant delay line - a trick I've recycled a few
times since then.

Great fun, but I don't know anybody who would describe it as "duck
soup" once they understood what was going on.

---
You sure do seem to harp a lot on that anti-555 crap.

Too bad you were never successful in using it in any of your
designs, (even though it's very easy to use) since if you had been
you might actually appreciate Camendzind's genius.

It never did what I wanted done.

If nothing else,
I think the use of the ratiometric voltage divider in order to
largely eliminate variations in output timing WRT supply voltage and
temperature variations was brilliant, as was the window detector
placed at the 1/3Vcc and 2/3Vcc taps of the divider.

That isn't exactly genius. Anyone whio can do enough calculus to find
minimum sensitivity conditions can demonstrate the same genius on a
wide variety of circuits. I spent a lot design time doing this on
various resistor networks when I was younger and doing serious analog
design.

Camenzind did come up with a great circuit for its time, but the
combination of crummy timer and crummy saturating switch didn't have
much to offer by 1974, when I might have used it, and has had even less
appeal since (except to people who are bit slow to learn new tricks -
when are you going to get into PLDs?).

YMMV, but I think you kind of begrudge him his success because you
think you're ever so much smarter than he is and yet...

I don't begrudge Hans Camenzind his success. Try to find some evidence
to support that daft allegation.

I''ve also got no reason to suppose that I'm smarter than Hans
Camenzind, nor have I ever made any such ridiculous claim.

You don't seem to have a particulary secure grasp of reality, do you.

 

[John Fields]

Don't be silly. First you libel me, then you claim it is up to me to
prove that your unsupported libel is false.

---
If it is, you should be able to prove it.

The reason I don't want to go slogging through your stuff is because
when I did present you with evidence you'd claim that what I found
was taken out of context or that it wasn't what you meant, or any
number of other excuses to try to get out of it.

The other reason I don't want to go slogging through your stuff is
that I just don't have the stomach for it.
---

You haven't raised the stakes at all - the electron beam
microfabricator included a laser driven inteferometric stage
positioning system, and hardware to map arbitrarily scaled data
defining the inegrated circuit masks to be written onto the
interoferometer measurements. We did fall short of full generality by
assuming that the wafer/mask to be written was within two degrees of
being square to the interferometer designed grid, but our customers
assured us that that was all the tolerance we needed.

Our electron beam provided better resolution than your
photolithographuc system ever could, and was doing write on the fly. I
think you have just een comprehensively trumped.

---
Actually, it sounds pretty much like what we were doing, which was
writing patterns generated on a CAD system directly onto an alumina
wafer by ablating its surface with a laser. We also used a laser
interferometer to get the stage's position, which in our case was a
shuttle driven pneumatically back and forth, with the
interferometric data being used to get data from memory which was to
be written at that position.
---

Not if you want 0.5nsec wide stroboscopic pulses (which required an
electrostatic beam-blanking system - albeit the boss would not spring
for the wide-voltage range version on which I'm named as the inventor.
Magnetic beam blanking is nice - we used it on the old EBMF 10.5
electron microfabricator - but it won't go sub-nanosecond nor anywhere
near it.

In fact the interesting part of that system, which I first proposed in
1983 (too late to have qualified for a patent) was the "multiple flash
per cycle" feature. We could keep track of up to 1024 phase points, and
build up our waveform/image at the 25MHz sampling rate of the system
(it should have been faster, but we started off with an unrealistic
completion date which created a lot of problems) rather than the repeat
cycle of the process we were following.

And we didn't need two detectors - a sing;e relatively fast
Everhart-Thornley detector above the final lens did everything we
needed. The fast-focussed photo-multiplier tube did need a fast output
amplifier, which incorporated an analog finite-impulse response filter
built around a lumped constant delay line - a trick I've recycled a few
times since then.

Great fun, but I don't know anybody who would describe it as "duck
soup" once they understood what was going on.

---
Yup, sounds neat.
---

It never did what I wanted done.

---
I suspect that's because there was always some reason you could come
up with why it was never satisfactory. Probably because you
considered it to be so far beneath your lofty designs that you'd
have nothing to do with it.
---

That isn't exactly genius. Anyone whio can do enough calculus to find
minimum sensitivity conditions can demonstrate the same genius on a
wide variety of circuits. I spent a lot design time doing this on
various resistor networks when I was younger and doing serious analog
design.

Camenzind did come up with a great circuit for its time, but the
combination of crummy timer and crummy saturating switch didn't have
much to offer by 1974, when I might have used it, and has had even less
appeal since (except to people who are bit slow to learn new tricks -
when are you going to get into PLDs?).

---
If you mean use them, then when I need to, if ever. They just don't
excite me very much and I've always been able to do what I needed to
without them using cheap, easily obtained parts, so what's the big
deal. I notice from an earlier post that you're itching to get your
hands on some of Xilinx's stuff but you're waiting for an
"opportunity" to come along? Why not just buy what you need and get
started.
---

I don't begrudge Hans Camenzind his success. Try to find some evidence
to support that daft allegation.

---
Just a feeling...
---

I''ve also got no reason to suppose that I'm smarter than Hans
Camenzind, nor have I ever made any such ridiculous claim.\

---
How about the: "That isn't exactly genius."... paragraph above?

You seem to be setting yourself up as a judge of what constitutes
genius and what doesn't, thereby putting yourself above him by
declaring his work "not genius". Strangely, what I said was that it
was "brilliant". The "genius" part was in a different context.
---

 

[[email protected]]

I don't care *that* much about about your opinion.

The reason I don't want to go slogging through your stuff is because
when I did present you with evidence you'd claim that what I found
was taken out of context or that it wasn't what you meant, or any
number of other excuses to try to get out of it.

The other reason I don't want to go slogging through your stuff is
that I just don't have the stomach for it.
---

Oh, come on - this exchange has been going on for a couple of days, and
you seem to have read most of the stuff I've posted. If my posts did
turn your stomach. you'd be too busy retching to respond.

---
Actually, it sounds pretty much like what we were doing, which was
writing patterns generated on a CAD system directly onto an alumina
wafer by ablating its surface with a laser. We also used a laser
interferometer to get the stage's position, which in our case was a
shuttle driven pneumatically back and forth, with the
interferometric data being used to get data from memory which was to
be written at that position.
---

Except that you were working at a larger scale, and slower - we had a
shaped beam electron source, which could write a shape - a rectangle in
the range 100nm to 10um -in less than a microsecond (I can't remember
the exact number) if the area was less than 1 or two square microns.
Part of the design was a gigaword random access memory with 72-bit
words plus eight bits of error correction and detection information. We
managed to publish the design

http://portal.acm.org/citation.cfm?id=45948.45966

---
Yup, sounds neat.
---


---
I suspect that's because there was always some reason you could come
up with why it was never satisfactory. Probably because you
considered it to be so far beneath your lofty designs that you'd
have nothing to do with it.
---

Dream on. The stuff I've worked on has included some very crude fixes -
through we did try and get rid of the cruder stuff. I was never all
that pleased with my driver for the magnetic blanking circuit on the
EBMF 10.5 - it was (just) fast enough, and didn't blow up when the
service engineers shorted the output to ground - but when I dropped in
on Cambridge Instruments (by then renamed) in the late 1990's they were
still using it, some 15 years later, with the lumped constant delay
line, and the largely capacitatively coupled drive to the output MOSFET
and all, none of which I was all that proud of, but hadn't been able to
improve.

---
If you mean use them, then when I need to, if ever. They just don't
excite me very much and I've always been able to do what I needed to
without them using cheap, easily obtained parts, so what's the big
deal.

Fewer parts, less board space, and the facility to offer more
complicated logic than you can reasonably cram in with standard parts.
Back in 1975 I thought up a way of minimising the low frequency noise
coming out of a PWM driver, and couldn't put it into a practical
circuit until 1993 when it just fitted into an ICT 7024 - it is in
figure 7 of my milli-degree controller paper in Measurement Science and
Technology, volume 7 pages 1653-1664 published in 1996.

I notice from an earlier post that you're itching to get your
hands on some of Xilinx's stuff but you're waiting for an
"opportunity" to come along? Why not just buy what you need and get
started.
---

Motivation and time. I've actually got a stick of surface mount parts,
but solder has probably already oxidised the point where they will be a
swine to mount - the idea that I was working out ddn't work out quite
the way I expected, and the next critical point involves doing a messy
mechanical drawing with QCAD, which I've yet to get working.

The application is the thing. The technique he used to get the
application to work is sort of routine for properly trained engineers.

You seem to be setting yourself up as a judge of what constitutes
genius and what doesn't, thereby putting yourself above him by
declaring his work "not genius". Strangely, what I said was that it
was "brilliant". The "genius" part was in a different context.
---

The arguement is about where the ingenious innovation was made. You
seem to be over impressed by elementary calculus, and insufficiently
respectful of of the trick of finding the right combination of features
for the time.

Nobody is asking you to believe the bits you don't understand. That
would be unreasonable, though you'd profit by a less skeptical
approach.

 

[[email protected]]

---
Forgot to mention...

This is USENET, Bill, and if you think anyone's going to be
interested in learning PLD when what they really want is a one-off
they can wire up themselves and get working with the least amount of
hassle, then you're just fucking insane.

I know - anything you can't do by tacking diodes around a 555 is a
hassle.
Other people have learnt to master more than one or two devices.

Do keep in mind that the PLD handles all the logic - there isn't a lot
left to wire up after you have programmed the PLD, and that saves a
load of time, space, money and potential unreliability.

Also, I just went over to the Xilinx site and looked up prices on
their Cool-Runner stuff.

Pick me up off the floor, OK?

I'm laughing so hysterically it's all I can do to type this without
meaking missteaks!

Pity that you couldn't remember the prices that brought on this
hysteria.
I got 15 XCR3032XL-10PCG44C for $1.70 each in June 2006. That doesn't
strike me as expensive for use in a one-off. But then you do design and
price everything as if it was going to manufacturered in thousands -
one of those habits that "professional" designers develop and can't
seem to lose, if you really are an example of this interesting breed.

 

[[email protected]]

Not according to the QA department. This stuff went into power stations
and oli refineries and everybdy involved was rather picky.

Oh, well...
---



---
So you're a proponent of recurrent production costs in lieu of
proper training? How much money do you think you've "saved" over
the years by doing it that way?
---

Quite a lot. In particular, service engineers who are prepared to
travel all over the globe are a rare breed, and both George Kent and
Cambridge Instruments hired as many as they could find. They could
afford to be too picky about the their trainability. The design
engineers understood that keeping the service engineers happy was part
of their job - if the service engineer got fractious, we were next in
line to spend six weeks in Seoul.

The worst I copped was a week in Nice in the middle of winter, and that
was sorting ot a mess that the marketing department had got us into,
but we were all encouraged to be careful.

Final test was a different kind of problem. They worked down the
corridor, and if they got stuck the good ones had a tendency to stick
their head around the door and ask or advice, which used up design
time. The bad ones invented their own solutions to what they perceived
as the problem, which you'd find out about when it appeared in the
"proposed modifications" file - usually some two hundred items long,
which appeared on the desk of any design engineer when he (or she) was
between projects.

If the design wasn't transparent to the final test technicians, you
always ran the risk of the machine going out the door distinctly
maladjusted, and the quality of the final test technicians was always a
bit erratic - if we we doing well, we'd just hired a bunch of new
technicians of variable quality who were still being trained,and if we
were doing badly, the good technicians would get themselves a more
secure job somwhere else.

One time I designed a circuit that used an un-trimmed - thus cheap -
Analog Devices multiplier to do a job, and wrote a procedure that let
me set up the two trimpots required in about ten minutes. I got called
into final test when the first machine went through to find that the
boss of final test and his star technician had been fiddling all day
trying to do the adjustments that I then did in the usual ten minutes.

Total cost (in techniican time) was about $300. I promptly modified the
circuit to use the more expensive laser trimmed multiplier, and did the
offsets on the rest of that batch (about 5 electron microscopes)
myself. We weren't expecting to sell more than about fifty of that
model before we obsoleted it with the first fully computer controlled
electron microscope, so my blunder with the cheap part cost us more
than I could have saved over the whole production run by using the
cheaper part.

 

[JoeBloe]

Jim Thompson wrote:

On Tue, 05 Dec 2006 04:00:07 GMT, Robert Baer


Jim Thompson wrote:


On Mon, 04 Dec 2006 05:27:34 GMT, Robert Baer



Jim Thompson wrote:



On Mon, 04 Dec 2006 00:03:56 GMT, Robert Baer




Jim Thompson wrote:



On Sun, 03 Dec 2006 19:19:05 GMT, Robert Baer


[snip]


That ratio is temperature sensitive...


What "ratio" is that?

...Jim Thompson

The ratio of the ersistor calues in the (comparitor) divider.


What makes you think resistor ratios have a TC?

Solid ratios is the only reason we can build analog IC's at all.

...Jim Thompson

I suggest that you do some measuring...


I suggest you get you head out of your ass. I've been designing IC's
since the beginning of time... ratiometric is what it's all about.

...Jim Thompson

Do tell; that is ASS-u-ME-ing that the ratios are *constant*.


Who do you think you are, Eeyore or some similarly IGNORANT person?

Please explain on me how the ratios are not. (Assuming you have even
the vaguest clue about resistor TYPES.)

...Jim Thompson
Sounds like you may need an education in electronics...


Just like a Usenet IDIOT to mouth off like an ass instead of giving
the explanation.

I know this really must be a BEAR for you to cope with, but he is
right.

WHO is it you think is right, me or Baer? I can't tell from your
attributions.

Neither. He's being rude to Baer for being wrong, and rude to you for
mouthing off like an ass instead of giving a comprehensible explanation

You're an idiot. Anyone with half a brain can tell that it was the
baretard that I was "after" in both cases.

- preferrably one that covers the fact that the area ratios actually
acheived on an integrated circuit include a manufacturing tolerance.

hygroscopic.

It all depends on the voltage. Figure that one out, ditz.

 

[[email protected]]

On Wed, 06 Dec 2006 17:38:15 -0800, JoeBloe

Jim Thompson wrote:

On Tue, 05 Dec 2006 04:00:07 GMT, Robert Baer


Jim Thompson wrote:


On Mon, 04 Dec 2006 05:27:34 GMT, Robert Baer



Jim Thompson wrote:



On Mon, 04 Dec 2006 00:03:56 GMT, Robert Baer




Jim Thompson wrote:



On Sun, 03 Dec 2006 19:19:05 GMT, Robert Baer


[snip]


That ratio is temperature sensitive...


What "ratio" is that?

...Jim Thompson

The ratio of the ersistor calues in the (comparitor) divider.


What makes you think resistor ratios have a TC?

Solid ratios is the only reason we can build analog IC's at all.

...Jim Thompson

I suggest that you do some measuring...


I suggest you get you head out of your ass. I've been designing IC's
since the beginning of time... ratiometric is what it's all about.

...Jim Thompson

Do tell; that is ASS-u-ME-ing that the ratios are *constant*.


Who do you think you are, Eeyore or some similarly IGNORANT person?

Please explain on me how the ratios are not. (Assuming you have even
the vaguest clue about resistor TYPES.)

...Jim Thompson
Sounds like you may need an education in electronics...


Just like a Usenet IDIOT to mouth off like an ass instead of giving
the explanation.

I know this really must be a BEAR for you to cope with, but he is
right.

WHO is it you think is right, me or Baer? I can't tell from your
attributions.

Neither. He's being rude to Baer for being wrong, and rude to you for
mouthing off like an ass instead of giving a comprehensible explanation

You're an idiot. Anyone with half a brain can tell that it was the
baretard that I was "after" in both cases.

Irrelevant. I figure Jim is in more serious need of stirring, and your
semi-literate posts weren't doing the job I wanted done.

It all depends on the voltage. Figure that one out, ditz.

They are diffused resistors and thus voltage dependent, as I've
mentioned before. Try doing some reading before you start slinging
criticism.

 

[John Fields]

Not according to the QA department. This stuff went into power stations
and oli refineries and everybdy involved was rather picky.

---
And mounting the resistor vertically would have made it more likely
to fail? What a bunch of wankers you were.
---

Quite a lot. In particular, service engineers who are prepared to
travel all over the globe are a rare breed, and both George Kent and
Cambridge Instruments hired as many as they could find. They could
afford to be too picky about the their trainability. The design
engineers understood that keeping the service engineers happy was part
of their job - if the service engineer got fractious, we were next in
line to spend six weeks in Seoul.

---
Yeah, right. A service engineer who couldn't understand a 3-input
RDL AND? Get off it Sloman, you're as full of shit as ever.
---

The worst I copped was a week in Nice in the middle of winter, and that
was sorting ot a mess that the marketing department had got us into,
but we were all encouraged to be careful.

Final test was a different kind of problem. They worked down the
corridor, and if they got stuck the good ones had a tendency to stick
their head around the door and ask or advice, which used up design
time. The bad ones invented their own solutions to what they perceived
as the problem, which you'd find out about when it appeared in the
"proposed modifications" file - usually some two hundred items long,
which appeared on the desk of any design engineer when he (or she) was
between projects.

If the design wasn't transparent to the final test technicians, you
always ran the risk of the machine going out the door distinctly
maladjusted,

---
That's ridiculous. There always needs to be someone responsible to
test the equipment before it goes out the door, not some bunch of
half-assed techs who are twiddling pots.
---

One time I designed a circuit that used an un-trimmed - thus cheap -
Analog Devices multiplier to do a job, and wrote a procedure that let
me set up the two trimpots required in about ten minutes. I got called
into final test when the first machine went through to find that the
boss of final test and his star technician had been fiddling all day
trying to do the adjustments that I then did in the usual ten minutes.

---
Then, I suspect, your "procedure" was badly written. Plus, you
should never use pots. When I worked for Racal-Milgo we weren't
allowed to design in pots for _any_ reason. Seems you learned your
lesson the hard way. Well, at least it had a good ending since your
customers didn't wind up inheriting a problem which should never
have been there in the first place.

So you think "transparent" design involves ten minutes of fiddling
with a pair of trimpots? What a load of crap.
---

 

[[email protected]]

The local theory was that the resistors could vibrate on the mounting
wire and eventually the wire could fatigue through.

Life was a little too short to try and persuade QA any different - we
had better things to do.

It takes time to make sense of a complex circuit diagram, and realising
a digital function with analog components doesn't speed up the process.
You are welcome to shit on your service engineers as much as you like.
We treated ours as colleagues. They weren't servicing just one machine,
but a variety of different machines, so they did have to consult the
circuit diagrams pretty frequently.

And - granting our QA department - using that particular trick wouldn't
have saved us anything anyway.

---
That's ridiculous. There always needs to be someone responsible to
test the equipment before it goes out the door, not some bunch of
half-assed techs who are twiddling pots.
---

Grow up. That sort of work is pretty boring, and if you try and get
smart people to do it they get bored and find themselves another job.

It was iterative, and the final test guys didn't follow it. I could
have rewritten it, but one go around had already cost more than using
the untrimmed multiplier was ever going to save.

Plus, you
should never use pots. When I worked for Racal-Milgo we weren't
allowed to design in pots for _any_ reason. Seems you learned your
lesson the hard way. Well, at least it had a good ending since your
customers didn't wind up inheriting a problem which should never
have been there in the first place.

I've designed out a lot of pots in my time, but we knew how much they
cost, and how long final test took to set them (and what that cost). In
the application the untrimmed multiplier, two pots and a ten minute
set-up procedure should have saved money - around $4 per machine.

So you think "transparent" design involves ten minutes of fiddling
with a pair of trimpots? What a load of crap.
---

It looked perfectly transparent to me and to my boss and to his
procedure-reading side-kick(who was a very intelligent guy who was very
good at "misunderstanding" ambiguous procedure descriptions). I still
don't know what threw the technicians - it certainly wasn't worth
spending the time to find out.

No, I don't - the cheaper part was some $10 cheaper than the trmmed
multiplier. Maximum total savings was thus $500 over 50 machines, less
$100 worth of pots and $200 worth of setting-up time, if the
technicians could have set it up as fast as I did.

 

[tv]

Hi all,

My name's ananth, from india, a novice hobby electronics enthusiast .
a year back, i got a PSoC kit to play around with and i implemented a
few of their app notes, including one about operation from 1.5AA
battery as the PSoC includes an FET switch as an onchip peripheral
which can be used to build a boost convertor.
it requires some extra components. i did a simple project from 1.5
everready AA cell (i think some push buttons and led--sorry do not
remember).
the smallest of devices is an 8 pin one and all members of the family
are available in very small packages (though i have not used anything
other than dip).
only some external discrete's are required which can be got in small
packages.
i used a few ic's from 27xxx series which i got as samples. cypress has
a lot of app notes , including an2286 which talks of simulating 555
using psoc and an2097 which talks of using onchip fet as switched mode
pump.
a visit to www.cypress.com/psoc/ might help and may be one could
contact the cypress fae team for more help.
going by what has been discussed here, i feel with a good 32k crystal
the accuracies required may be achievable.

regards
ananth