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Possible Duplicate:
Resistors with ends of the same colour

I know the values of resistors if they are gold-colored at the end. When both ends are the same, such as brown-r-bk-bk-brown, I am in problem. How to know which side has the last color and which side is the starting end? Does thickness of band matter?

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Ghufran Khan
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    Usually the tollerance band is distinguished somehow. It might be a little fatter, or there is a bigger space between it and the other bands. – Olin Lathrop May 11 '12 at 11:43
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    @Olin - I often find the difference so small that I don't want to rely on it. The multimeter is always nearby. :-) – stevenvh May 11 '12 at 13:28

2 Answers2

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Try both directions.

Very likely only one of both values is member of the particular E-series.

Sometimes the tolerance ring is somehwhat thicker than the others or its distance to the end of the resistor is smaller, but AFAIK this is not reliable.

If in doubt, measure.

Curd
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brown-red-black-black-brown = 120\$\Omega\$, 1%
brown-black-black-red-brown = 10k\$\Omega\$, 1%

Both are valid E12 values, but the 120\$\Omega\$ is not an E48 (2%) or E96 (1%) value! So most likely 10k\$\Omega\$. A DMM will give you certainty.

E96: ... 113, 115, 118, 121, 124, 127, ...

stevenvh
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  • "the 120Ω is not an E48 (2%) or E96 (1%) value! So most likely 10kΩ". I can't agree with this conclusion. In my experiance 1% resistors with values from the E24 series are extremely common, probablly more so than those with values from the E48 series. – Peter Green May 31 '19 at 17:16