Charles Barker@I-O INC
03/09/98 01:19 PM

I always thought the "R" stood for a decimal point. i.e. 10R3 meant 10.3
ohms.





[log in to unmask] on 03/07/98 09:41:48 PM

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To:   [log in to unmask]
cc:    (bcc: Charles Barker/US/I-O INC)
Subject:  Re: [TN] Chip resistors




Darcy,
    You pretty much got the basics...3 digits usually are +/- 5% tolerance,
and 4 digits are +/- 1% or better. Most resistor manufacturers try and stay
to
the same standard, but there are still a bunch that have their own way of
marking. To be sure of the value, a good ol' ohm meter can't be beat.
     The colors may indicate a tolerance in some cases, in others they
don't.
You might run across resistors that will have a letter in the middle of the
digits. For example using 10K ohms as the value, you may see something like
this: 10R3
the ten is the significant figure, the R the tolerance, and the 3 is the
number of zeros. Depending on who made it, the R could stand for 5%, or 1%,
or
whatever the resistor manufacturer wants...it makes you wanna scream don't
it?
     At one time in the past, I almost had the rework people wanting to
lynch
me because I had them rework a bunch of resistors that I thought was the
wrong
tolerance. They only had three digits and USUALLY they're 5%, the BOM
called
for a 1% resistor. Come to find out that these were really 1%'ers...the
vendor
who sold them took regular 5% resistors and measured each one screening out
the less precise ones before they taped them up, needless to say, I bought
a
few ladies lunch that day!!  (GRIN)
                                                 I was a bunch O' help,
wasn't
I?
                                                       -Steve Gregory-
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