Wah??? You had to actually touch the TV to change the channel? From: John Woodgate [mailto:[email protected]] Sent: Wednesday, June 20, 2018 11:52 AM To: [email protected] Subject: Re: [PSES] ESD question
It's probably not ethnicity directly, but skin resistance. This varies greatly between people. Long years ago, when we had touch-contact channel change on TVs, we had to double the sensitivity so that one particular person in the lab could work it. When we took sets to a show, someone turned up who couldn't work it. We found it necessary to double the sensitivity again. If you think about a person standing in the ESD field as a large (poorly-) conducting body, you can see why the effect can occur. John Woodgate OOO-Own Opinions Only J M Woodgate and Associates www.woodjohn.uk<http://www.woodjohn.uk> Rayleigh, Essex UK On 2018-06-20 14:06, Jim Hulbert wrote: Somewhere, I have copies of the discharge waveforms (captured on a scope) from human subjects that Michael King recruited during his studies. As I recall, the amplitude of the ESD pulses was limited to about 10kV as the subjects started to balk. I believe Michael’s studies also led to the development of the Andy Hish 255 probe. The waveform from that probe, which was a long wand grasped in the hand, was influenced by the human body capacitance of the technician performing the tests. There was a situation some years ago in our EMC Lab, where my associate and I both consistently passed a product for ESD using the Andy Hish probe, which was our corporate standard tester at the time. However, an intern working with us consistently failed the product. We did our best to make sure we were all following the exact same test technique. The only difference my associate and I could think of was that the intern was of a different ethnicity than us. We didn’t dare mention that, however. Jim Hulbert - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]<mailto:[email protected]>> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe)<http://www.ieee-pses.org/list.html> List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]<mailto:[email protected]>> Mike Cantwell <[email protected]<mailto:[email protected]>> For policy questions, send mail to: Jim Bacher <[email protected]<mailto:[email protected]>> David Heald <[email protected]<mailto:[email protected]>> - ---------------------------------------------------------------- This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list. To post a message to the list, send your e-mail to <[email protected]> All emc-pstc postings are archived and searchable on the web at: http://www.ieee-pses.org/emc-pstc.html Attachments are not permitted but the IEEE PSES Online Communities site at http://product-compliance.oc.ieee.org/ can be used for graphics (in well-used formats), large files, etc. Website: http://www.ieee-pses.org/ Instructions: http://www.ieee-pses.org/list.html (including how to unsubscribe) List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected]> Mike Cantwell <[email protected]> For policy questions, send mail to: Jim Bacher: <[email protected]> David Heald: <[email protected]>
