Strong resonance

A resonance that has relatively low loss. An impedance plot will show a low dip at series resonance (i.e., low impedance) and high peak at parallel resonance (i.e., high impedance), as compared to a weak resonance.

If a strong resonance is near the nominal operating frequency of the power supply, then the power supply may tend to run at this strong resonance, even if this resonance is not the primary resonance.