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SESK: Stuff Everyone Should Know · sesk.info/hamg-g6a06

Why should wire-wound resistors be avoided in RF circuits?

Their inductance can make circuit performance unpredictable.

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  1. Its tolerance value would not be adequate
  2. It could overheat
  3. Its inductance could make circuit performance unpredictable ✔

Why: A wire-wound resistor is a coil of wire, so it also acts like an inductor. At radio frequencies that unwanted inductance makes the circuit behave unpredictably.

Huh, didn't know that: An inductor operated above its self-resonant frequency becomes capacitive.

The dad joke
What did the man do when he paid for his resistors? He paid ohmage.
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References

Answer: Its inductance could make circuit performance unpredictable. A wire-wound resistor is a coil of wire, so it also acts like an inductor. At radio frequencies that unwanted inductance makes the circuit behave unpredictably.

  1. NCVEC 2023-2027 General Class Pool and Syllabus (6th Errata, Feb 4 2026) ncvec.org/downloads/General%20Class%20Pool%20and%20Syllabus%202023-2027%20Public%20Release%20with%206th%20Errata%20Feb%204%202026.pdf
    The resistor’s inductance could make circuit performance unpredictable
    Checked 2026-10-11.

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