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[SOLVED] Resistor marked value vs. actual outside tolerance?

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RobAinscough

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I purchased a variety pack of resistors 1/4w 1% tolerance ranging from 0\[\Omega\] to 10M\[\Omega\]. I haven't tested every single resistor, but I did test many in the lower end from 0.5 to 10\[\Omega\] and most of them were not as marked and outside tolerance ... for example:

0.5 marked was 0.8 actual resistance
1.0 marked was 1.3 actual resistance

outside the 1% tolerance ... once I got above 10\[\Omega\] marked they started to fall within tolerance.

Is this common? Just a bad resistor manufacturer or something else?

Cheers, Rob.
 

Note that the same difference of above 0.3Ω happens in both, don't seem it could be due to the resistance of the multimeter cable?
 
Resistances smaller than 1 ohm may be tricky to measure accurately with a conventional multimeter. You need to use a 4-point probe.

But I am surprised that resistors in the range 1-10 are also not showing accurately. Did you check with the multimeter specs?
 
Thanks for the responses, took me a while to check with my Oscilloscope, but it does indeed seem to be my DMM has about 0.3\[\Omega\] in cables and/or internal ... Mystery solved.

Cheers, Rob.
 

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