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At resonance, what impedance does a parallel LC circuit present?

Maximum, the opposite of series resonance.

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  1. Minimum
  2. Maximum ✔
  3. Exactly zero

Why: A parallel resonant circuit has maximum impedance at resonance, the opposite of a series circuit. The inductor and capacitor effectively cancel each other, so almost no current is drawn from the source.

Huh, didn't know that: With a constant current source, a parallel circuit also develops its maximum voltage at resonance.

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References

Answer: Maximum. A parallel resonant circuit has maximum impedance at resonance, the opposite of a series circuit. The inductor and capacitor effectively cancel each other, so almost no current is drawn from the source.

  1. Engineering LibreTexts, AC Electrical Circuit Analysis, 8.4 Summary eng.libretexts.org/Bookshelves/Electrical_Engineering/Electronics/AC_Electrical_Circuit_Analysis%3A_A_Practical_Approach_(Fiore)/08%3A_Resonance/8.4%3A_Summary
    producing maximum impedance at resonance, and the opposite of the series impedance curve.
    Checked 2026-10-11.
  2. NCVEC 2024-2028 Amateur Extra Question Pool, E5A04 (4th errata, Feb. 4, 2026) www.ncvec.org/downloads/2024-2028%20Extra%20Class%20Question%20Pool%20and%20Syllabus%20Public%20Release%20with%204th%20Errata%20Feb%204%202026.pdf
    A. Approximately equal to circuit resistance
    Checked 2026-10-11.

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