FIG. 26 illustrates an attenuation curve 26-1 of resonant energy when the operation of an LC resonant circuit of the wireless power transmitter 100 suspends in a state that there exist only the wireless power receiver 200 (in a state that the LC resonant circuit is short-circuited) and the wireless power transmitter 100 without an external metal material 300.
FIG. 27 is a view illustrating a waveform in which a current waveform of FIG. 23 and a current waveform of FIG. 26 overlap, wherein it is seen that the attenuation curve 23-1 of resonant energy in FIG. 23 and the attenuation curve 26-1 of resonant energy in FIG. 26 are not affected by the existence or non-existence of the wireless power receiver 200 (in a state that the LC resonant circuit is short-circuited). In other words, it is seen that the attenuation factor of resonant energy in FIG. 23 and the attenuation factor of resonant energy in FIG. 26 are not so different from each other.
