The International Electrotechnical Commission (IEC) has published a standard for high-voltage test techniques, which is IEC 60060-1:2013. This standard provides general definitions and requirements for high-voltage testing of electrical equipment and systems. The standard is divided into several parts, and Part 1 covers the general definitions and requirements.
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The sound was a physical blow, like a giant snapping a whip inside the room. The air smelled of ozone. On the oscilloscope screen, a bright green line traced a perfect arc. Smooth. Clean. iec 60060-1 pdf
IEC 60060-1: High-voltage test techniques – Part 1: General definitions and test requirements.
He froze.
You can download the PDF version of IEC 60060-1:2013 from the IEC website or other online sources.
He looked at his data. His peak was fine. His tail time was 48 microseconds—acceptable. But his front time? THWACK
The PDF described the "Virtual Origin" ($O_1$). It explained how to draw a line through the 30% and 90% points of the rising curve to determine the effective start of the impulse.