This discussion clarifies the differences between magnetic resonance and magnetic induction in the context of wireless electricity. Magnetic resonance utilizes oscillating currents in coils to create a non-radiative, near-field magnetic field, allowing for efficient energy transfer over greater distances. In contrast, magnetic induction relies on primary and secondary coils closely positioned to transfer energy, resulting in significant energy loss over longer distances. The resonant method is superior for applications requiring distance, as it maintains oscillation in the coil, unlike non-resonant systems that quickly dissipate energy.
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Resonant transfer works by making a coil ring with an oscillating current. This generates an oscillating magnetic field. Because the coil is highly resonant, any energy placed in the coil dies away relatively slowly over very many cycles; but if a second coil is brought near it, the coil can pick up most of the energy before it is lost, even if it is some distance away. The fields used are predominately non-radiative, near field (sometimes called evanescent waves), as all hardware is kept well within the 1/4 wavelength distance they radiate little energy from the transmitter to infinity.
Non-resonant coupled inductors, such as typical transformers, work on the principle of a primary coil generating a magnetic field and a secondary coil subtending as much as possible of that field so that the power passing though the secondary is as close as possible to that of the primary. This requirement that the field be covered by the secondary results in very short range and usually requires a magnetic core. Over greater distances the non-resonant induction method is highly inefficient and wastes the vast majority of the energy in resistive losses of the primary coil.