resistor nomenclature

On Tue, 15 Jul 2008 16:06:36 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

John Larkin wrote:

I do not. I use correct scientific notation, and correct engineering
units, not some weird amateur audio thing.

You need a serious waking up.

Graham
Click to expand...
I design critical electronics for the biggest scientific and aerospace
enterprises on the planet. I'm not about to look like some hobbyist
when I present my stuff to senior scientists at national laboratories,
or Fellows of giant aerospace conglomerates.

What do you have against SI units and scientific notation?

http://en.wikipedia.org/wiki/Si_units#SI_writing_style

John
 
On Tue, 15 Jul 2008 16:05:50 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

John Larkin wrote:

Eeyore wrote:
John Larkin wrote:
mrdarrett@gmail.com wrote:

http://en.wikibooks.org/wiki/Practical_Electronics/Resistors

So does R2 mean 0.2 ohms? (0,2 ohms for those of you east of the
Atlantic)

Michael

Horrible circuit, horrible nomenclature.

The right way to write 0.2 ohms is "0.2" or "0.2R", if you can't make
the omega symbol.

0R2 in this part of the world, always avoiding the decimal point.

Graham

The physicists and chemists and aerospace engineers of the world use
scientific notation, and their decimal points don't fall off the page
and pile up on the rug. I work with these people, and I'd rather use
their notation than something made up by some european hobbyist
magazines.

It has nothing to do with hobby magazines and everthing to do with the IEC
AIUI.
Click to expand...
YDUI.

http://en.wikipedia.org/wiki/Si_units

John
 
John Larkin wrote:

Eeyore wrote:
John Larkin wrote:

I do not. I use correct scientific notation, and correct engineering
units, not some weird amateur audio thing.

You need a serious waking up.

I design critical electronics for the biggest scientific and aerospace
enterprises on the planet. I'm not about to look like some hobbyist
when I present my stuff to senior scientists at national laboratories,
or Fellows of giant aerospace conglomerates.

What do you have against SI units and scientific notation?
Click to expand...
I have everything FOR them and unambiguous values like 0R33 form part of
that. Decimal points have no place on schematics.

Grahgam
 
John Larkin wrote:

Eeyore wrote:
John Larkin wrote:
Eeyore wrote:
John Larkin wrote:
mrdarrett@gmail.com wrote:

http://en.wikibooks.org/wiki/Practical_Electronics/Resistors

So does R2 mean 0.2 ohms? (0,2 ohms for those of you east of the
Atlantic)

Michael

Horrible circuit, horrible nomenclature.

The right way to write 0.2 ohms is "0.2" or "0.2R", if you can't make
the omega symbol.

0R2 in this part of the world, always avoiding the decimal point.

Graham

The physicists and chemists and aerospace engineers of the world use
scientific notation, and their decimal points don't fall off the page
and pile up on the rug. I work with these people, and I'd rather use
their notation than something made up by some european hobbyist
magazines.

It has nothing to do with hobby magazines and everthing to do with the IEC
AIUI.

YDUI.

http://en.wikipedia.org/wiki/Si_units
Click to expand...
I see nothing there that contradicts my very sensible view.

Would you you care to elabotate ?

Graham
 
On Jul 15, 6:47 am, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
On Tue, 15 Jul 2008 10:06:47 GMT, Ross Herbert



rherb...@bigpond.net.au> wrote:
On Mon, 14 Jul 2008 20:42:51 -0700, John Larkin
jjlar...@highNOTlandTHIStechnologyPART.com> wrote:

:On Mon, 14 Jul 2008 14:56:03 -0700 (PDT), mrdarr...@gmail.com wrote:
:
:>http://en.wikibooks.org/wiki/Practical_Electronics/Resistors
:
:>So does R2 mean 0.2 ohms? (0,2 ohms for those of you east of the
:>Atlantic)
:
:>Michael
:
:Horrible circuit, horrible nomenclature.
:
:The right way to write 0.2 ohms is "0.2" or "0.2R", if you can't make
:the omega symbol.
:
:John

I don't agree John :)

If you can't make the Omega symbol you either use "0.2 ohms" or "0R2" where the
R replaces the decimal point.

I do not. I use correct scientific notation, and correct engineering
units, not some weird amateur audio thing.

John
Click to expand...

So you spec 2E-1 for your 0.2 ohm resistors?

I actually do agree with you, being an SI kind of guy myself...

0.0821 L-atm/(mol K), or 8.314 J/(mol K)? (just kidding)

Michael
 
On Tue, 15 Jul 2008 23:04:24 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

mrdarrett@gmail.com wrote:

So you spec 2E-1 for your 0.2 ohm resistors?

Believe it or not, that style was briefly once used.
Click to expand...
---
Hell, I use it all the time on LTspice schematics.

JF
 
On Tue, 15 Jul 2008 17:12:22 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

Decimal points have no place on schematics.

Grahgam
Click to expand...
So how do you express 33.25 MHz? 95.2 nanoseconds? Turns ratio of
2.5:1?

33MHz25

95ns2

2T5:1

but if decimal points slide off the page, I suppose colons do, too.

And of course, comments and notes can't have periods.

John
 
John Larkin wrote:
And of course, comments and notes can't have periods.
Click to expand...

No, but Donkeys do, and quite often.


--
http://improve-usenet.org/index.html

If you have broadband, your ISP may have a NNTP news server included in
your account: http://www.usenettools.net/ISP.htm

Sporadic E is the Earth's aluminum foil beanie for the 'global warming'
sheep.
 
On Jul 15, 3:04 pm, Eeyore <rabbitsfriendsandrelati...@hotmail.com>
wrote:
mrdarr...@gmail.com wrote:
So you spec 2E-1 for your 0.2 ohm resistors?

Believe it or not, that style was briefly once used.

Graham
Click to expand...

What's wrong with that style? I kinda like it - lots more than R2 or
0R2.

Michael
 
On Tue, 15 Jul 2008 06:47:48 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

:On Tue, 15 Jul 2008 10:06:47 GMT, Ross Herbert
:<rherber1@bigpond.net.au> wrote:
:
:>On Mon, 14 Jul 2008 20:42:51 -0700, John Larkin
:><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
:>
:>:On Mon, 14 Jul 2008 14:56:03 -0700 (PDT), mrdarrett@gmail.com wrote:
:>:
:>:>http://en.wikibooks.org/wiki/Practical_Electronics/Resistors
:>:>
:>:>So does R2 mean 0.2 ohms? (0,2 ohms for those of you east of the
:>:>Atlantic)
:>:>
:>:>Michael
:>:
:>:Horrible circuit, horrible nomenclature.
:>:
:>:The right way to write 0.2 ohms is "0.2" or "0.2R", if you can't make
:>:the omega symbol.
:>:
:>:John
:>
:>
:>I don't agree John :)
:>
:>If you can't make the Omega symbol you either use "0.2 ohms" or "0R2" where
the
:>R replaces the decimal point.
:
:I do not. I use correct scientific notation, and correct engineering
:units, not some weird amateur audio thing.
:
:John
:

So, if your documentation specifies say a "0.2R" resistor and the decimal point
goes missing in printing, the result is then "0 2R". How can you claim that this
is not ambiguous? You need to get with the times John. I can say this with
impunity because I am 68 and have been working in electronics since the mid 50's
and a new idea which makes written resistor values non-ambiguous seems wise to
me.
 
On Wed, 16 Jul 2008 02:48:35 GMT, Ross Herbert
<rherber1@bigpond.net.au> wrote:

On Tue, 15 Jul 2008 06:47:48 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

:On Tue, 15 Jul 2008 10:06:47 GMT, Ross Herbert
:<rherber1@bigpond.net.au> wrote:
:
:>On Mon, 14 Jul 2008 20:42:51 -0700, John Larkin
:><jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:
:
:>:On Mon, 14 Jul 2008 14:56:03 -0700 (PDT), mrdarrett@gmail.com wrote:
:>:
:>:>http://en.wikibooks.org/wiki/Practical_Electronics/Resistors
:>:
:>:>So does R2 mean 0.2 ohms? (0,2 ohms for those of you east of the
:>:>Atlantic)
:>:
:>:>Michael
:>:
:>:Horrible circuit, horrible nomenclature.
:>:
:>:The right way to write 0.2 ohms is "0.2" or "0.2R", if you can't make
:>:the omega symbol.
:>:
:>:John
:
:
:>I don't agree John :)
:
:>If you can't make the Omega symbol you either use "0.2 ohms" or "0R2" where
the
:>R replaces the decimal point.
:
:I do not. I use correct scientific notation, and correct engineering
:units, not some weird amateur audio thing.
:
:John
:

So, if your documentation specifies say a "0.2R" resistor and the decimal point
goes missing in printing, the result is then "0 2R". How can you claim that this
is not ambiguous?
Click to expand...
How about if the "2" goes missing? Then what do you do?


You need to get with the times John.
Click to expand...
Get with the times? I use a CAD program that doesn't lose characters.
And a B-size laser printer that prints like pages from Sunset
magazine. Our digital copier is so good that the only way you can tell
the copies from the original is that they're warmer; it even feeds,
collates, and staples the copy, or emails you a PDF of the original.
But we seldom copy schematics; the printers and the copiers are
networked, so it's easier to just spool another one from the library
server, finish your latte, then go pick it up.

Are you still drawing schematics on butcher paper with dull pencils,
and copying them on the fly-spec'd machine at the supermarket? Or
exposing blueprints in sunlight?

I can say this with
impunity because I am 68 and have been working in electronics since the mid 50's
and a new idea which makes written resistor values non-ambiguous seems wise to
me.
Click to expand...
One of the first things they taught us in engineering school was to
make clear decimal points. It's surprising how many people can't
master the technique.

But the real issue is that, in a professional outfit, a schematic is a
reference drawing, and does not control configuration. What does
control configuration is an assembly drawing and a bill of materials.
And the BOM doesn't call out resistors by value, it calls them out by
stock number. Since it's common for an ECO to change a BOM, or to have
several dash-numbered versions of one pcb assembly, each with its own
BOM, the schematic can't be relied on to call out the actual
resistance, if R112 is indeed installed at all. Production doesn't
pull a 4.99K 0805 1% resistor; they pull stock number 302-3761.


John
 
On Tue, 15 Jul 2008 20:43:24 -0700, John Larkin
<jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

:
:One of the first things they taught us in engineering school was to
:make clear decimal points. It's surprising how many people can't
:master the technique.
:
:

Since my main point is that "the decimal point can go missing" I will
concentrate on that.

It may be all well and good while the ONLY documentation is that provided by
yourself - which I am sure will be perfectly legible and accurate. The problem
comes when establishments down the track make photo-copies of your documentation
for other purposes, perhaps of dubious quality. This is where the decimal point
can go missing and the ambiguity will arise. While there may be no need at all
to copy YOUR documentation and the problem may NEVER arise in your case, the
same can not be said for other establishments. It is therefore wise to establish
a standard which applies to everyone and which can not become ambiguous.
 
On Tue, 15 Jul 2008 16:05:50 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> wrote:

John Larkin wrote:

Eeyore wrote:
John Larkin wrote:
mrdarrett@gmail.com wrote:

http://en.wikibooks.org/wiki/Practical_Electronics/Resistors

So does R2 mean 0.2 ohms? (0,2 ohms for those of you east of the
Atlantic)

Michael

Horrible circuit, horrible nomenclature.

The right way to write 0.2 ohms is "0.2" or "0.2R", if you can't make
the omega symbol.

0R2 in this part of the world, always avoiding the decimal point.

Graham

The physicists and chemists and aerospace engineers of the world use
scientific notation, and their decimal points don't fall off the page
and pile up on the rug. I work with these people, and I'd rather use
their notation than something made up by some european hobbyist
magazines.

It has nothing to do with hobby magazines and everthing to do with the IEC
AIUI.

Heck, even John Fields with whom I've crossed swords a few times agrees it's
the best method. And he's right !
Click to expand...
---
The best method in _some_ instances, like ASCIImatics on USENET, where
terseness matters.

1K2, for example, is one space shorter than 1.2K, making a line wrap
less likely on a wide drawing.

If you've ever seen any of the "formal" drawings I've published on
abse you might recall that I use SI notation and military reference
designations, as I also do on any drawings I supply to my clients.

JF
 
On Wed, 16 Jul 2008 11:21:21 GMT, Ross Herbert
<rherber1@bigpond.net.au> wrote:

On Tue, 15 Jul 2008 20:43:24 -0700, John Larkin
jjlarkin@highNOTlandTHIStechnologyPART.com> wrote:

:
:One of the first things they taught us in engineering school was to
:make clear decimal points. It's surprising how many people can't
:master the technique.
:
:

Since my main point is that "the decimal point can go missing" I will
concentrate on that.
Click to expand...
OK, but proper hand-drawn decimal points never went missing, nor do
CAD decimal points. What a strange compulsion.

It may be all well and good while the ONLY documentation is that provided by
yourself - which I am sure will be perfectly legible and accurate. The problem
comes when establishments down the track make photo-copies of your documentation
for other purposes, perhaps of dubious quality. This is where the decimal point
can go missing and the ambiguity will arise. While there may be no need at all
to copy YOUR documentation and the problem may NEVER arise in your case, the
same can not be said for other establishments. It is therefore wise to establish
a standard which applies to everyone and which can not become ambiguous.
Click to expand...
We rarely provide schematics to outside organizations, and if the do
it's as PDF files, not paper. I assume that my customers can afford
decent printers, too.

The "standard" is SI units and nomenclature. The "no decimal points"
mess is an amateur affectation. My customers are scientists and
aerospace engineers; they would think I'd gone senile if I started
putting 0R118 next to R118.

John
 
On Jul 16, 7:08 am, John Larkin
<jjlar...@highNOTlandTHIStechnologyPART.com> wrote:
The "standard" is SI units and nomenclature. The "no decimal points"
mess is an amateur affectation. My customers are scientists and
aerospace engineers; they would think I'd gone senile if I started
putting 0R118 next to R118.
Click to expand...
But, R118 is a NAME that has to be looked up in an
associated table to find out what it refers to. 0R118 is
a VALUE (and an odd one, who uses 0.118 ohm
resistors - the number of digits suggests a sub-1%
part).

In 'R118' the R designates a resistor. In '0R118', it
designates a radix point.

When time comes to look inside my thermostat, the little
glued-into-the-lid schematic would be more useful if
it has a blurry '0R118' next to a resistor symbol than
if it tries to fit in a full specification (size, fire rating,
value, tolerance, etc). Certainly the lid of the thermostat
doesn't have room for a tabulated parts list.

There's a place for clear engineering documents, and
a place for slapdash notations glued inside access
panels. Both are useful. If the lack of standards is
bothersome, let's write one up. RFC-0R118, perhaps?
 
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