resistor nomenclature

Guest
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
 
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)
Click to expand...
---
I think it needs a zero in front of it, like 0R2

JF
 
On Jul 14, 3:08 pm, John Fields <jfie...@austininstruments.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)

---
I think it needs a zero in front of it, like 0R2

JF
Click to expand...

Ah.

http://www.redcircuits.com/Page2.htm

I thought Resistor 18 was a 22 ohm.

Is it 0.22 ohm?

Michael
 
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)
Click to expand...
I'd write it 0R2 myself. Unless it's simply a component reference
designator like R17 which is what it appears to be on that page.

Graham
 
On Mon, 14 Jul 2008 15:25:04 -0700 (PDT), mrdarrett@gmail.com wrote:

On Jul 14, 3:08 pm, John Fields <jfie...@austininstruments.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)

---
I think it needs a zero in front of it, like 0R2

JF


Ah.

http://www.redcircuits.com/Page2.htm

I thought Resistor 18 was a 22 ohm.

Is it 0.22 ohm?

Michael
Click to expand...

I would assume that R18 is 0.22 ohms, based on the general format of
the parts list.

I would much prefer to see the value written as 0R22, so it can't be
confused with R22, the twenty-second resistor in the circuit.



--
Peter Bennett, VE7CEI
peterbb4 (at) interchange.ubc.ca
GPS and NMEA info: http://vancouver-webpages.com/peter
Vancouver Power Squadron: http://vancouver.powersquadron.ca
 
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
Click to expand...
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
 
On Mon, 14 Jul 2008 23:54:30 +0100, "christofire"
<christofire@btinternet.com> wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
news:ugjn7454bj03ii1m975o9eni73ubdpvele@4ax.com...
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)

---
I think it needs a zero in front of it, like 0R2

JF


... and not everyone 'east of the Atlantic' uses a comma for a decimal
point. How crass!
Click to expand...
Not to mention that everyone is east of the Atlantic.
--
John
 
"Paul E. Schoen" <pstech@smart.net> wrote in message
news:487c3475$0$25552$ecde5a14@news.coretel.net...
"John Larkin" <jjlarkin@highNOTlandTHIStechnologyPART.com> wrote in
message news:kq6o74ts5gcvig0fhinsi9nfd9oe4ut8fn@4ax.com...
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.

The problem is that the decimal point can become faint and disappear
when photographic copies are made, or when the schematic is converted to
a graphics format. With just the leading zero above, it is fairly
obvious even if the decimal were not there, but what about 2.2 ohms? I
have become used to the newer convention. You can also use 200 mOhms
(milliohms) to avoid confusion.

Paul
Click to expand...

That is the question as I understand it. What Is the newer convention ?

Wayne
 
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.
Click to expand...
0R2 in this part of the world, always avoiding the decimal point.

Graham
 
Wayne wrote:

That is the question as I understand it. What Is the newer convention ?
Click to expand...
0R2 or 200m (but not 200M). Since some CAD packages I know (Orcad comes to
mind) automatically capitalise, 0R2 would be better.

Graham
 
John Fields 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)

---
I think it needs a zero in front of it, like 0R2
Click to expand...
That is the modern thinking. However, unless I'm looking at a different
part of the page the '2' was simply a reference designator as in in R1,
R2, R3, ... Rn etc.

Graham
 
mrdarrett@gmail.com wrote:

On Jul 14, 3:08 pm, John Fields <jfie...@austininstruments.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)

---
I think it needs a zero in front of it, like 0R2

JF

Ah.

http://www.redcircuits.com/Page2.htm

I thought Resistor 18 was a 22 ohm.

Is it 0.22 ohm?
Click to expand...
Yes. And a bloody odd place to put a resistor too. I assume it's to
'compensate' for the lack of an output coil to decouple the amp from stray
capacitance in the load..

I'd query the integrity of that design.

In place of R18, I'd use about 15-20 turns of reasonable gauge 'magnet
wire' wound on a 3/4" former in parallel with say 8R2. Look at any typical
competent amp design.

Graham
 
Peter Bennett wrote:

I would assume that R18 is 0.22 ohms, based on the general format of
the parts list.
Click to expand...
Yes.


I would much prefer to see the value written as 0R22, so it can't be
confused with R22, the twenty-second resistor in the circuit.
Click to expand...
I totally agree.

Graham
 
christofire wrote:

"John Fields" <jfields@austininstruments.com> wrote in message
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)

---
I think it needs a zero in front of it, like 0R2

JF

... and not everyone 'east of the Atlantic' uses a comma for a decimal
point. How crass!
Click to expand...
The use of the comma and the 'decimal' point as separators is entirely
reversed compared to the UK-US convemtion in some countries. All the more
reason not to use them.

Graham
 
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.

If you use the R after the value there is a further source of possible ambiguity
for those who are satisfied with the use of R as replacing the decimal point.
 
On Mon, 14 Jul 2008 15:25:04 -0700 (PDT), mrdarrett@gmail.com wrote:

On Jul 14, 3:08 pm, John Fields <jfie...@austininstruments.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)

---
I think it needs a zero in front of it, like 0R2

JF


Ah.

http://www.redcircuits.com/Page2.htm

I thought Resistor 18 was a 22 ohm.

Is it 0.22 ohm?
Click to expand...
---
Yes.

JF
 
On Tue, 15 Jul 2008 10:17:58 +0100, Eeyore
<rabbitsfriendsandrelations@hotmail.com> 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
Click to expand...
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.

This 2k7 stuff is for amateurs, who I suppose build things from copies
of copies of bad schematics, like the audio amp referenced above.

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

John
 
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.
Click to expand...
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 !


This 2k7 stuff is for amateurs, who I suppose build things from copies
of copies of bad schematics, like the audio amp referenced above.
Click to expand...
You need to get up to date.

Graham
 
John Larkin wrote:

I do not. I use correct scientific notation, and correct engineering
units, not some weird amateur audio thing.
Click to expand...
You need a serious waking up.

Graham
 
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