On the other hand, in the state of FIG. 5B, outside the current i2b, the magnetic field strength due to the current i2a is inversely proportional to (r+d), the magnetic field strength due to the current i2b is inversely proportional to (r?d), and the directions of the induction magnetic fields H2a, H2b are opposite to each other. Therefore, at a distant position separated by a very large distance r (r>>d) from the intermediate position, the influence of the induction magnetic fields H2a, H2b becomes almost the same, and the induction magnetic fields H2a. H2b cancel each other out.
That is, in the example of FIG. 5B, the outside of each position of the currents i2a, i2b becomes a canceling region, and noise can be reduced within that range. However, noise increases in the range on the inner side of each position of the currents i2a, i2b.
<Examples of Waveforms>
FIG. 6 is a time chart illustrating an example of a voltage waveform and a noise waveform.
