A spectral resistor based on the constitute law of “elasticity of electricity” derived from the Riemann-Lebesgue lemma is provided to build a substantial order-∞ resonant tank. The substantial order-∞ resonant tank according to embodiments of the present invention can function as many different roles such as an electric filter, a harmonic and sub-harmonic power waveform distortion filter, a dynamic damper, a dynamic impedance matching circuit and a kind of electromagnetic wave absorbing material. By attaching an order-∞ resonant tank according to the present invention to an ordinary system with equivalent inductance in a suitable topology as an electric filter, a substantial snubber network, or so-called DeLenzor, is obtained. The duality of an electric system can be handled by coupling the system with an order-∞ resonant tank according to the present invention, and thus the disadvantageous effects caused by the duality of the system can be canceled immediately without any drawbacks. Furthermore, the reactive (or so-called regenerated) power caused by the duality of the electric system can be recycled according to embodiments of the present invention.