A detuned reactor connected in series with a capacitor (L-C-circuit) creates a resonance frequency "tuned away" from the harmonic frequencies occurring in the mains. For all frequencies above the resonance frequency, the L-C-circuit becomes inductive, i.e. appears no longer as a capacitance: no destructive parallel resonances can occur with other inductances of the mains. At mains frequency, however, the LC-circuit is capacitive and fulfills its power factor correction task.