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Author: John FieldsDate: 18:08 14-07-08
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Author: christofireDate: 18:54 14-07-08
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Author: EeyoreDate: 22:49 14-07-08
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Author: Peter BennettDate: 22:52 14-07-08
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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
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
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Author: John LarkinDate: 23:42 14-07-08
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Author: Paul E. SchoenDate: 01:20 15-07-08
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"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
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Author: John O'FlahertyDate: 02:59 15-07-08
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Author: WayneDate: 04:08 15-07-08
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"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
That is the question as I understand it. What Is the newer convention ?
Wayne
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Author: EeyoreDate: 05:17 15-07-08
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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
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Author: EeyoreDate: 05:20 15-07-08
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Wayne wrote:
> That is the question as I understand it. What Is the newer convention ?
0R2 or 200m (but not 200M). Since some CAD packages I know (Orcad comes to
mind) automatically capitalise, 0R2 would be better.
Graham
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Author: EeyoreDate: 05:22 15-07-08
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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
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
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Author: EeyoreDate: 05:27 15-07-08
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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?
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
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Author: EeyoreDate: 05:30 15-07-08
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Peter Bennett wrote:
> I would assume that R18 is 0.22 ohms, based on the general format of
> the parts list.
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.
I totally agree.
Graham
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Author: EeyoreDate: 05:32 15-07-08
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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!
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
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Author: Ross HerbertDate: 06:06 15-07-08
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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.
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Author: John FieldsDate: 07:38 15-07-08
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Author: John LarkinDate: 09:45 15-07-08
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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
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
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Author: John LarkinDate: 09:47 15-07-08
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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
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