ESD: IEC 61000-4-2, MIL-STD-461 CS118, ISO 10605, et. al.
The basis for most ESD (electrostatic discharge) tests comes from IEC 61000-4-2, “Testing and measurement techniques–Electrostatic discharge immunity test”. The active 2008 version can be purchased here, with a new version expected in 2025. ISO 10605, “Road vehicles — Test methods for electrical disturbances from electrostatic discharge” (purchase 2023 version here) adopted the test method for the automotive industry. MIL-STD-461 included ESD testing for the first time with Rev G (freely available here) with the CS118 test method–and it looked pretty familiar. See comparisons below.
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If you have questions about ISO10605 or IEC 61000-4-2, you can see if there are answers in the freely available MIL-STD-461G CS118 or related appendix (Section A.5.16) before purchasing from IEC or ISO.
Testing is specified for units that are powered off (representing the danger from discharge when being handled or installed) and when turned on (representing threats present in its operating environment). They also include air and contact discharge, with air discharge generally being more severe. Contact discharge is mating two conductive objects at different potentials together and seeing the surge of charge transfer. Air discharge is when you reach for a metal doorknob on a dry/cold day and feel an actual spark just before you touch the door. Maximum testing voltages should be adjusted based on the expected operating conditions (how often humans interact with the unit, if it is installed in a humidity-controlled environment, etc.).
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ANSI C63.16, “Guide for Electrostatic Discharge Test Methodologies and Acceptance Criteria for Electronic Equipment”, is an available guidance document for ESD testing (the 2016 version is available for purchase here; a new version has been drafted and is currently going through ANSI approvals). It gives additional context
Almost all ESD test standards and commercially available ESD test guns/simulators base their waveforms off the human body model (HBM). The CS118 version is below.
However, there are cases where the main threat does not come from human interaction. Generally speaking the industries have determined that testing based on the HBM is adequate to identify most hardware weaknesses to ESD (although the ANSI C63.16 working group will tell that’s definitely not 100% true). I was once looking into a case where the main threat to a satellite orbiting in Low Earth Orbit was definitely going to be spacecraft charging, and did some research to see if there were other standard models available.
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The only one I was able to find was from an outdated military standard, MIL-STD-1541A (1987) (freely available here). You can see an alternate discharge model below, and the document has information about ways to vary different parts of the circuit to address different threat waveforms.
MIL-STD-331D (download here) includes circuit values for helicopter-based discharges for fuzing systems and ignition protection devices as well, to be inserted into a more traditional IEC 61000-4-2 circuit setup. Appendix A.5.8.3.2 of MIL-STD-464D also has information on helicopter-borne discharges & ordnance.
