1983 年 6 巻 38 号 p. 55-61
First, an occurrence region of showering arc in breaking silver contacts was made clear in this paper. In this region, the spectra of voltage waveforms of showering arc and the radio noise E (dB) caused by this arc were measured. Next, from the results of measurements, it was found that ; 1) as the dielectric breakdown voltage V_B increases, E (dB) increases. 2) generally, the damped oscillation appears just after the dielectric breakdown, and this oscillation is one of the main reason of radio noise.