What Ed said made sense in that the ear canal is going to allow a breakdown at a lower potential than elsewhere, so even though the potential difference between phone/earbuds and me was perhaps not as a large as between me and some other object completely isolated from me, it was enough, and as many have noted, the inner ear is going to be more sensitive than other parts of the body that are dryer and less sensitive.
Ken Javor Phone: (256) 650-5261 From: Doug Smith <[email protected]> Reply-To: <[email protected]> Date: Sat, 6 Jan 2018 22:37:58 -0500 To: <[email protected]> Subject: Re: [PSES] ESD question 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/tt050101.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. Doug On Sun, 7 Jan 2018 00:17:35 +0000, Edward Price wrote: Ken: My guess would be that there was an unobserved discharge from the fabric to the dangling earphone cord, which then discharged into your body capacitance in your ear canals (which were extra conductive due to trapped moisture filling the ear canals and the earbud orifices). I wonder if a vapor of perspiration and earwax will fluoresce? Ed Price WB6WSN Chula Vista, CA USA From: Ken Javor [mailto:[email protected]] Sent: Friday, January 05, 2018 6:21 PM To: [email protected] Subject: [PSES] ESD question Just curiosity. Spent a week in the cold frozen north. Single Fahrenheit digits (above and below zero) outside, snow on the ground, 70 degrees inside dry air. Was able to generate some pretty decent lightning simulations walking around and especially stripping a bed that had some sort of fuzzy (no doubt synthetic material) blanket. While stripping the bed, I was listening to a podcast on an iPhone, through wired earbuds. I could hear the discharges through the earbuds. That was some sort of interference, but not the question of interest here. What was interesting is that the bigger sparks not only zapped where I made contact (typically hands) but also from the earbuds to my inner ear (ouch)! That¹s not what I said, but close enough. The iPhone was in a leather pouch suspended from by belt. The hook around the belt was metal, the belt was leather, and there were (denim cotton) pants between the hook on the inside of the belt and my skin. To my understanding, the iPhone and earbuds should have been at near or the same potential I was, and even if not, it was certainly no sort of ground completely isolated from anything except me. So the question is why was there such a potential difference between iPhone and earbuds and me that my ears were zapped? Ken Javor Phone: (256) 650-5261 - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. 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