Re: NEEDED: Color-code for carbon-film resistors- update

[Rubywand <rubywand@swbell.net>]

Edhel Iaur, Esq. writes ...
> 
> On Sun, 21 Jun 1998 15:44:05 -0500, Rubywand <rubywand@swbell.net>
> wrote:
> 
> ...
> >Tolerance (4th band)
> >
> >Gold is           5%
> >Silver is        10%
> >no color is      20%
> 
> There's also a new red band used on the tolerance end, isn't there?
> For some value less than 5%, I believe.


     That seems to be correct, although it does not seem to be common
information. I checked a "graphical resistance calculator" web page

http://www.dannyg.com/javascript/res2/resistor.htm

and a couple other sources. None mentions a red tolerance band. However,
a check through our resistor collection produced several with red for
band 4 and all of these measured very close to the value indicated by
bands 1-3.

     All of the red tolerance resistors also had a 5th band (usually
white) which, maybe, indicates temperature coefficient. Anyway, it looks
like we are dealing with an extension of the old EIA code.

     Thanks for the information! Perhaps red = 2%; but, for now, I've
added it to the chart as "<5%".




Color   Digit   Multiplier (when 3rd band)  Example 

Black     0       x1              --  Red Red Black =         22 Ohms
Brown     1       x10             --  Blue Grey Brown =      680 Ohms
Red       2       x100            --  Orange White Red =    3900 Ohms
Orange    3       x1000           --  Yellow Violet Orange = 47k Ohms
Yellow    4       x10000          --  Red Green Yellow =    250k Ohms
Green     5       x100000         --  Orange Orange Green = 3.3M Ohms 
Blue      6       x1000000        --  Red Yellow Blue =      24M Ohms
Violet    7       x10000000       --  ...
Grey      8       x100000000
White     9       x1000000000

Gold      -       x 0.1           -- Brown Brown Gold =      1.1 Ohms
Silver    -       x 0.01          -- Orange White Silver =  0.39 Ohms


Tolerance (4th band)

Red is           <5% (courtesy of Edhel Iaur)
Gold is           5%
Silver is        10%
no color is      20%

Example: Grey Red Orange Gold      is 82k Ohms  +/- 5%
Example: Brown Black Green Silver  is  1M Ohms  +/- 10%

Note: carbon resistors almost always err on the high side.



Rubywand