stion that hopefully someone can shed a little light
>> upon.
>>
>> I have wondered for as long as I've been involved in things electrical,
>> why standard component values are what they are. Text books are of no
>> use and I've done more than a few internet
Another carbon composition resistor anecdote :
In the early days of UL1459, 2nd ed. (c. 1989), with the advent of
overvoltage testing (or as CSA called it, fire hazard testing; now
referred to as power-cross testing) on telecommunications ports, one
manufacturer used GDTs and 5 W series limiting r
_
From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: Wednesday, March 14, 2007 7:30 AM
To: emc-p...@ieee.org
Subject: Re: OT: standard component values
I have heard that carbon composition resistors are no longer allowed to be
used in commercial products because they burn
rg
> Subject: Re: OT: standard component values
>
> Peter and list members,
>
> Related to this subject, many years ago one of
> the electronics magazines published (in text
> format) a Basic program by Jan Axelson that
> calculates standard resistor values for any
> de
huge
response.
Scott B. Lacey
On 13 Mar 2007 at 8:24, Tarver, Peter wrote:
> An off-topic question that hopefully someone can shed a little light
> upon.
>
> I have wondered for as long as I've been involved in things electrical,
> why standard component values are what they a
Hi Ed and all:
Ed asks:
"BTW, does anyone know when component manufacturers started using this
tolerance progression? From my own observation, the system was in place for
1930's era design. Was it codified under some old EIA standard, or is it
even older?"
The EIA did not exist in the '30's.
T
I'd like to thank all contributors to this thread. Little did I know
that such a seemingly small topic it would turn into so lively a
discussion, with so many responses.
Regards,
Peter L. Tarver, PE
ptar...@ieee.org
CONFIDENTIALITY
This e-mail message and any attachments thereto, is intended o
All,
I remember an application where a small value carbon resistor was
placed in a circuit to handle overloads which could result in a fire. This
was reliably demonstrated to fail in an open circuit under the fault
conditions evaluated.
When, at a later date, it w
In message , dated Wed, 14
Mar 2007, Ken Javor writes:
>I have heard that carbon composition resistors are no longer allowed to
>be used in commercial products because they burn when mistreated.
But in many applications they can't be mistreated enough to burn. How do
you burn up a 1 megohm? A
In message
,
dated Wed, 14 Mar 2007, "Price, Ed" writes:
>BTW, does anyone know when component manufacturers started using this
>tolerance progression? From my own observation, the system was in place
>for 1930's era design. Was it codified under some old EIA standard, or
>is it even older?
Fax: (+44) 1245 453571
Mob: (+44) 7801 723735
P Please consider the environment before printing this email.
From: Ken Javor [mailto:ken.ja...@emccompliance.com]
Sent: 14 March 2007 14:30
To: emc-p...@ieee.org
Subject: Re: OT: standard component values
I have heard that carbon composition res
: emc-pstc@listserv.ieee.org
Date: Wed, 14 Mar 2007 06:08:37 -0800
To: emc-p...@ieee.org
Subject: RE: OT: standard component values
From: John Woodgate [mailto:j...@jmwa.demon.co.uk]
Sent: Wednesday, March 14, 2007 1:37 AM
To: emc-p...@ieee.org
Subject: Re: OT: standard component values
From: John Woodgate [mailto:j...@jmwa.demon.co.uk]
Sent: Wednesday, March 14, 2007 1:37 AM
To: emc-p...@ieee.org
Subject: Re: OT: standard component values
In message <45f7a47b.2040...@dctolight.net>, dated Wed, 14 Mar 2007, Fred
Townsend writes:
>Gentlemen what you say may appl
In message <45f7a47b.2040...@dctolight.net>, dated Wed, 14 Mar 2007,
Fred Townsend writes:
>Gentlemen what you say may apply to some components but with regard to
>5, 10, and 20% composition resistors it is dead wrong.
The question was where the 'preferred values' came from. Not how carbon
co
rance resistor.
From: Robert Johnson <mailto:john...@itesafety.com>
Organization: ITE Safety
List-Post: emc-pstc@listserv.ieee.org
Date: Tue, 13 Mar 2007 23:33:27 -0500
To: ted.eck...@apcc.com
Cc: emc-p...@ieee.org
Subject: Re: OT: standard component values
Do I assume th
In message <45f77b17.4070...@itesafety.com>, dated Tue, 13 Mar 2007,
Robert Johnson writes:
>Do I assume this means that a 10% 1K resistor will have values between
>900 and 950 ohms or between 1050 and 1100 ohms since the resistors
>measuring between 950 and 1050 will have been placed in the 5
To: ted.eck...@apcc.com
> Cc: emc-p...@ieee.org
> Subject: Re: OT: standard component values
>
> Do I assume this means that a 10% 1K resistor will have values between
> 900 and 950 ohms or between 1050 and 1100 ohms since the resistors
> measuring between 950 and 1050 will have b
"PSTC 1"
> emc-p...@ieee.org cc
>
>
From: John Woodgate [mailto:j...@jmwa.demon.co.uk]
Sent: Tuesday, March 13, 2007 9:20 AM
To: emc-p...@ieee.org
Subject: Re: OT: standard component values
In message
,
dated Tue, 13 Mar 2007, "Tarver, Peter"
writes:
>Or maybe there's a mathematical reason that hasn'
In message ,
dated Tue, 13 Mar 2007, "Powell, Doug" writes:
>Years ago, I even had a program for my HP-67 calculator that would take
>a desired value and show me the nearest standard value.
There is a small app at:
http://www.miscel.dk/MiscEl/miscel.html
which does a lot more than that. I'm
In message
,
dated Tue, 13 Mar 2007, "Tarver, Peter"
writes:
>Or maybe there's a mathematical reason that hasn't occurred to me, like
>some arithmetic progression, or even simple phobias or prejudices.
Ah, you youngsters! (Strokes long, white beard.)
It's based on geometric progression and
;; 'PSTC 1'
Subject: RE: standard component values
Quote: "These values were supposed to have been derived from the
mathematical series of equally spacing values logarithmically for each
decade."
http://www.eng-tips.com/viewthread.cfm?qid=71035&page=5
Dave Cuthbert
http://www.pc-control.co.uk/resistor-eia.htm
Regards,
Chris
From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of David
Cuthbert
Sent: 13 March 2007 15:38
To: 'Tarver, Peter'; 'PSTC 1'
Subject: RE: standard component values
Quote: "These values were supp
logarithmic; a three AWG size jump
constitutes a resistance change factor of two.
> From: "Tarver, Peter"
> Date: Tue, 13 Mar 2007 08:24:28 -0700
> To: "PSTC 1"
> Subject: OT: standard component values
>
> An off-topic question that hopefully someone can shed a lit
] On Behalf Of Barker, Neil
Sent: 13 March 2007 15:34
To: 'Tarver, Peter'; PSTC 1
Subject: RE: standard component values
Peter,
My understanding is that each series, E12, E24, etc increments approximately
according to the corresponding tolerance such that adjacent values
approximately m
453616
Fax: (+44) 1245 453571
Mob: (+44) 7801 723735
P Please consider the environment before printing this email.
From: Tarver, Peter [mailto:peter.tar...@sanmina-sci.com]
Sent: 13 March 2007 15:24
To: PSTC 1
Subject: OT: standard component values
An off-topic question that hopefully
cc
Subject
03/13/2007 10:24 OT: standard comp
.@ieee.org] On Behalf Of Tarver,
Peter
Sent: Tuesday, March 13, 2007 9:24 AM
To: PSTC 1
Subject: OT: standard component values
An off-topic question that hopefully someone can shed a little light
upon.
I have wondered for as long as I've been involved in things electrical,
why standard compon
An off-topic question that hopefully someone can shed a little light
upon.
I have wondered for as long as I've been involved in things electrical,
why standard component values are what they are. Text books are of no
use and I've done more than a few internet searches on this in th
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