I found the following component but I don't know what it is. In particular, what does the ΩJ unit mean?

photo of component marked 5W 10mΩJ

  • 10
    \$\begingroup\$ the J is likely a separate symbol, probably referring to tolerance. \$\endgroup\$
    – Hearth
    Feb 18, 2022 at 14:36

2 Answers 2


That's not J for joules. It's probably J for 5% tolerance. The component is just a 10 mΩ resistor with a 5 W rating.

  • 3
    \$\begingroup\$ Probably we have a dupe somewhere on the site for this kind of code, but I wasn't able to turn it up with a bit of searching. \$\endgroup\$
    – hobbs
    Feb 18, 2022 at 14:37
  • 5
    \$\begingroup\$ electronics.stackexchange.com/a/484095/47070 \$\endgroup\$
    – JRE
    Feb 18, 2022 at 14:40

"J" means a resistor value tolerance of +/- 5% as per this site.

The resistor in question has a value of 10 milli-ohms (\$m\Omega\$).

It also applies to capacitors as per this wiki site: -

enter image description here


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