Engineers who are good at handling high voltage are in high demand from the industries. On the other hand, the students who have experience dealing with high voltage are becoming rare. High voltage engineering is based on the basics of electrical engineering, for instance, electromagnetics and electrical circuits. Even complicated phenomena at high voltage can often be clarified by analogy with an equivalent electrical circuit model. In this paper, we constructed a high-voltage education tool as a subject of the tracking phenomenon of the insulator surface. The phenomena were replaced with the electrical circuit model, and a simple numerical analysis was performed using the circuit model. The educational tool was used for high school and university students. In the test conducted before the lecture, about 40% of the students were able to replace the tracking phenomenon with the electrical circuit model. After the lecture, the questionnaire results showed that the experiment helped understand the phenomenon, but there were small barriers to the replacement with the electric circuit model. According to the comments from the students, it is inevitable that the electric circuit model has improved the understanding.

Most of the lighting in houses and commercial facilities has replaced to white LED lighting. Therefore, creatures such as moths attracted to fluorescent light and mercury lamp in the past are no longer less attracted. However, Parasteatoda tepidariorum are flocking to white LED lighting and nesting. We expected that the factor is Parasteatoda tepidariorum shows positive phototaxis to the wavelength contained in the white LED lighting. We investigated the phototaxis by the attraction experiment and the visibility by the electroretinogram (ERG) signal measurement. As a result of the investigation, we got the characteristics of Parasteatoda tepidariorum that high visibility and high attraction rate of the wavelength contained in the white LED. Therefore, we conclude that Parasteatoda tepidariorum will flock to the LED lighting devices because of positive phototaxis to the light of white LED.

In 1989 the International Electrotechnical Committee (IEC) adopted contact discharge testing of an electrostatic discharge (ESD) generator to reduce the variations in air discharge test results, and specified in IEC 61000-4-2 only the four waveform parameters (the rise time of the first peak current, the current value of the first peak, the current values at 30 ns and at 60 ns), also schematically showing a typical contact discharge current waveform. In 2008 the IEC offered an ideal contact current waveform along with a Heidler’s formula that allows calculating the current waveform from an ESD generator, whereas its scientific rationale is not provided. In this paper, human air discharges at charging voltages of ±8 kV are measured to validate the IEC ideal current waveform through waveform comparison. The result shows that measured current waveforms from human air discharges greatly change depending on the spark length, and the current waveform does not have the second peak in addition to the falling edge of the first peak seen in the IEC ideal current waveform. Nevertheless, there exists the first rising peak current with a rise time that satisfies the IEC standard, coming closest to the IEC ideal current. Furthermore, air discharge currents having almost the same rise times as those of the IEC ideal currents at different test voltages, which are calculated from an equivalent circuit previously proposed for human air discharges based on the IEC standard, are shown to be moderately consistent with the ideal current waveforms and also to meet with all the IEC specified requirements. This finding supports the validity of the IEC ideal current waveform in a sense that the IEC specified waveform reflects natural phenomena of human air discharges.

The air discharge currents from two humans having different physique with a wide range of charging voltages from ±1 kV to ±15 kV are measured via an IEC specified electrode to reveal that a specific relationship holds between the peaks per kV and rise-times regardless of human physique, charging voltages, polarities and spark lengths, which is also shown by analyzing a simplified equivalent circuit for human air discharge based on the IEC standard. This derives the specification required for the first peak waveform of the contact discharge method.