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Yageo's SMT capacitor datasheet lists the ESR vs. Frequency Curve show below:

enter image description here

Note that impedance (Z) is listed in units (W). How can this be understood? Why is impedance seemingly not measured in Ohms, as is customary?

Jacob R
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  • Does this answer your question? [What is impedance?](https://electronics.stackexchange.com/questions/3941/what-is-impedance) – tuskiomi Feb 03 '20 at 07:36
  • it's a very common inter-character set typo error, you get used to seeing it. – Neil_UK Feb 03 '20 at 07:39

2 Answers2

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W just means \$\Omega\$, so Ohms.

The small letter omega: \$\omega\$ looks a bit like a "w".

It is possible that a "W" was typed at the Y-axis of the graph but that this wasn't converted into the Greek character \$\Omega\$ when the pdf file was made.

Bimpelrekkie
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    This is a very common error seen in many datasheets, most likely a general issue with fonts or other parts of the process making the PDF. It does not take long before brains start to auto-correct that. – Justme Feb 03 '20 at 07:39
  • Omega maps to W in Windows Symbol font (IIRC), so it's likely that at some point a font substitution was made and "Symbol" was replaced by an ordinary font. These day there are better ways of inserting Greek letters but old methods are often still used – Chris H Feb 03 '20 at 16:46
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In addition to Bimpelrekkie's answer:

I wonder if it is a conversion error by PDF. The µ from µF is converted correctly. So, probably, the tool to make the graph didn't support Greek letters and therefore the author decided to use a letter coming closest to the Ω.

Huisman
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  • That or the author didn't double check when they generated the graph (as an embedded image) and *that* contained the non-converted "Ω", while actual text such as the legend up top with the proper Greek "µ" as originally entered came across just fine because Acrobat *is* capable of dealing with Greek characters and other oddities like that. – Doktor J Feb 03 '20 at 16:01