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
_
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
: 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
desired ratio. Either 5% or 1% values can
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.
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
In message c21d7120.52139%ken.ja...@emccompliance.com, dated Wed, 14
Mar 2007, Ken Javor ken.ja...@emccompliance.com 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
In message
e6acec5be8405b4e936c9e9bccac10241b6...@bb-corp-be1.corp.cubic.cub,
dated Wed, 14 Mar 2007, Price, Ed ed.pr...@cubic.com 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
) 1245 453571
Mob: (+44) 7801 723735
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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 resistors
-Post: 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 f...@dctolight.net writes:
Gentlemen what you say may
In message 45f7a47b.2040...@dctolight.net, dated Wed, 14 Mar 2007,
Fred Townsend f...@dctolight.net 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
Johnson mailto:john...@itesafety.com 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 this means that a 10% 1K
In message 45f77b17.4070...@itesafety.com, dated Tue, 13 Mar 2007,
Robert Johnson john...@itesafety.com 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
-0500
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 been placed in the 5
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% or better
stock?
Bob Johnson
ted.eck...@apcc.com wrote:
The standard resistor values are
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
be3336be85968d49be01e66d6e365b1e01b59...@sjc1amfpew01.am.sanm.corp,
dated Tue, 13 Mar 2007, Tarver, Peter peter.tar...@sanmina
In message
be3336be85968d49be01e66d6e365b1e01b59...@sjc1amfpew01.am.sanm.corp,
dated Tue, 13 Mar 2007, Tarver, Peter peter.tar...@sanmina-sci.com
writes:
Or maybe there's a mathematical reason that hasn't occurred to me, like
some arithmetic progression, or even simple phobias or prejudices.
The standard resistor values are selected to ensure that any resistor
manufactured can be marked as a valid part and sold. For 5% resistors,
each value is approximately 10% larger than the previous value. Anything
between 9.5 and 10.5 could be called 10 within 5%. Likewise, the 1%
resistor
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