smd resistors

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raym
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smd resistors

Post by raym » Thu Jan 17, 2002 7:35 pm

does any one know what the last digit is on a smd resistor is? This is the layout 1913 I know that the 191 is 190k but what is the 3 on the end . does it mean the wattage, or tolerance or other
Thanks Ray

L. Daniel Rosa
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Re: smd resistors

Post by L. Daniel Rosa » Thu Jan 17, 2002 9:09 pm

I would guess the last digit to be the multiplier. So 1913 would be 191k. If the fourth digit means something else then the resistonce would read as 190 ohms, not a standard value for three digit resistors. If you measure it with a DMM, that will tell you. Note that this may be a 1% or better resistor and most DMMs are not rated any tighter than this, so if it reads 190k it's within spec for a four digit code.

raym
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Re: smd resistors

Post by raym » Sat Jan 19, 2002 7:52 pm

<blockquote><font size="1" face="Verdana, Helvetica, sans-serif">quote:</font><hr>Originally posted by L. Daniel Rosa:
I would guess the last digit to be the multiplier. So 1913 would be 191k. If the fourth digit means something else then the resistonce would read as 190 ohms, not a standard value for three digit resistors. If you measure it with a DMM, that will tell you. Note that this may be a 1% or better resistor and most DMMs are not rated any tighter than this, so if it reads 190k it's within spec for a four digit code.<hr></blockquote>

Dean Huster
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Re: smd resistors

Post by Dean Huster » Sun Jan 20, 2002 8:01 pm

I had always assumed that 3-significant-figure resistors were 1% or better, but things seem to be changing. I'm finding a lot of 3-significant-figure thru-hole resistors with 5% tolerances. So far, the color codes have always followed the standard 5% values (that is, no 1% values with a 5% tolerance).<p>SMT 1% resistors, aside from the 4-digit value markings (3 significant figures + number of zeros) are usually printed on a blue background while the 5% values are on a black background. Anybody find any variances on this?
Dean Huster, Electronics Curmudgeon
Contributing Editor emeritus, "Q & A", of the former "Poptronics" magazine (formerly "Popular Electronics" and "Electronics Now" magazines).

R.I.P.

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