We've used an old o'scope to monitor the ESD event. Set it up nearby with a bit of wire for an antenna attached to a channel, adjust to trigger on the ESD event, and watch the waveform. A good contact discharge makes one kind of waveform and nearly good contact makes noticeably different waveform.
- Bill Indecision may or may not be the problem. --- On Fri, 5/29/09, John Woodgate <[email protected]> wrote: From: John Woodgate <[email protected]> Subject: Re: [PSES] ESD testing To: [email protected] Date: Friday, May 29, 2009, 11:19 AM In message <[email protected] <http://us.mc01g.mail.yahoo.com/mc/comp se?to=0ed66cd2c9bd0a459d54fb9119a60567f4a...@mailserver.lecotc.com> >, dated Fri, 29 May 2009, "Kunde, Brian" <[email protected] <http://us.mc01g.mail.yahoo.com/mc/[email protected]> > writes: > Is that true? Has anyone done tests to see the difference of the ESD pulse with a brand new sharp ESD Gun TIP vs a warn-out TIP that is no longer sharp? I would think that as long as you make good contact with the metal that the sharpness of the tip would have no or little affect on repeatability. Yes, 'as long as'. It's not easy to be sure that a non-conducting layer has been fully penetrated, so a sufficiently dull tip may give optimistic results. > > One last question. The TIPs on our ESD gun are made out of Brass and dull very quickly. They are very costly from the manufacturer so our machine shop has been making us new ones out of the same base material. However, because they dull so quickly I would like to have them made out of a harder material, such as Stainless Steel. Has anyone found that changing the tip material affects the repeatability of the ESD test? Figure 3 of IEC 6000-4-2 does not specify the material of the tip. It doesn't even say that it must be conducting! (It actually says that there may be an insulating covering, but I guess it doesn't mean over the sharp point!) I can't see any reason why a hard metal tip should not be used. The hard (austenitic) variety of stainless steel, however, is naturally hard to work. Depending on the machining required, something else might be better. I can't see why the tip has to be 12 mm diameter. Since it is, the body could be a low-cost material, such as alumin(i)um, with a much smaller, interchangeable sharp point embedded. Has anyone got a store of phonograph/gramophone needles? No, not thorn ones, or diamond-tipped! -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk Things can always get better. But that's not the only option. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - ---------------------------------------------------------------- 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] <http://us.mc01g.mai .yahoo.com/mc/[email protected]> > All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html List rules: http://www.ieee-pses.org/listrules.html For help, send mail to the list administrators: Scott Douglas <[email protected] <h tp://us.mc01g.mail.yahoo.com/mc/[email protected]> > Mike Cantwell <[email protected] <htt ://us.mc01g.mail.yahoo.com/mc/[email protected]> > For policy questions, send mail to: Jim Bacher: <[email protected] <http: /us.mc01g.mail.yahoo.com/mc/[email protected]> > David Heald: <[email protected] <http:/ us.mc01g.mail.yahoo.com/mc/[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.ieeecommunities.org/emc-pstc Graphics (in well-used formats), large files, etc. can be posted to that URL. Website: http://www.ieee-pses.org/ Instructions: http://listserv.ieee.org/request/user-guide.html 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]>
