Actually, inductive coupling (Faraday's law) can generate thousand of Volts near ESD events, enough to breakdown insulation barriers! Just get a di/dt of 40 Amps/ns (a 10kV or somewhat less contact discharge) near a loop and see what you get for 50 nH of inductance (not much) E = 40A/ns * 50 nH = 2,000 Volts
Doug Smith Sent from my iPhone IPhone: 408-858-4528 Office: 702-570-6108 Email: d...@dsmith.org Website: http://dsmith.org On Sun, Jan 7, 2018 at 8:09, Cortland Richmond <k...@earthlink.net> wrote: We are sometimes less than precise -- but it leads to interesting discussions. Cheers, Cortland Richmond -----Original Message----- From: Ken Javor Sent: Jan 7, 2018 9:28 AM To: Cortland Richmond , EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] ESD question Re: [PSES] ESD question Cortland: Faraday Law purely inductive coupling from an ESD event doesn't cause potentials that breakdown dielectric barriers; it induces potentials that cause bit shifts. But to answer John Woodgate’s question literally, enough charge buildup with some capacitance eventually yields a potential high enough to cause dielectric breakdown. Since that is basic, I assume I misinterpreted his post. Ken Javor Phone: (256) 650-5261 From: Cortland Richmond <k...@earthlink.net> Reply-To: Cortland Richmond <k...@earthlink.net> Date: Sun, 7 Jan 2018 06:23:07 -0500 To: <EMC-PSTC@LISTSERV.IEEE.ORG> Subject: Re: [PSES] ESD question Induction; I once saw motherboard testers shut down systems under test by just walking away from the work table at lunchtime. Sliding across the cloth chair seats generated a charge, and walking away biased the motherboards and shut everything down. (They didn't have the funds for antistatic protection – so for a few months, we had them spraying the chairs with a solution of water and detergent. You could tell who worked there because the seats of their pants were wet...) Cortland Richmond -----Original Message----- From: John Woodgate Sent: Jan 7, 2018 4:10 AM To: EMC-PSTC@LISTSERV.IEEE.ORG Subject: Re: [PSES] ESD question Philosophical issue there. If the field is really static, what changed to cause the spark to happen when it did, rather than at some other time? (A cosmic ray would breach the stasis.) John Woodgate OOO-Own Opinions Only J M Woodgate and Associates www.woodjohn.uk <http://www.woodjohn.uk> [http://www.woodjohn.uk] Rayleigh, Essex UK On 2018-01-07 03:37, Doug Smith wrote: Hi Ed and Ken, An ESD event can be produced without any direct addition of charge. It only takes an E field and two conductors near each other as in: http://emcesd.com/tt2001/tt060101.htm [http://emcesd.com/tt2001/tt060101.htm] http://emcesd.com/tt2001/tt050101.htm [http://emcesd.com/tt2001/tt050101.htm] <http://emcesd.com/tt2001/tt060101.htm> [http://emcesd.com/tt2001/tt060101.htm] Unobserved discharge not needed and generally is not involved with these type of events. Just a static E field will induce a spark. - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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