Subject: | |
From: | |
Reply To: | TechNet E-Mail Forum. |
Date: | Sat, 7 Mar 1998 22:41:48 EST |
Content-Type: | text/plain |
Parts/Attachments: |
|
|
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-
################################################################
TechNet E-Mail Forum provided as a free service by IPC using LISTSERV 1.8c
################################################################
To subscribe/unsubscribe, send a message to [log in to unmask] with following text in the body:
To subscribe: SUBSCRIBE TechNet <your full name>
To unsubscribe: SIGNOFF TechNet
################################################################
Please visit IPC web site (http://jefry.ipc.org/forum.htm) for additional information.
For the technical support contact Dmitriy Sklyar at [log in to unmask] or 847-509-9700 ext.311
################################################################
|
|
|