Re: [PSES] ESD question

I also have a copy of those waveforms and a paper Michael King wrote on one of my older Macs, can likely find it if needed. I was lucky to have been mentored by Michael King when I was younger. He is a great scientist/engineer and had a great effect on me. I was fortunate to have four great

Re: [PSES] [SI-LIST] Re: Measurement Dilema - THE EXPLANATION!

egards, Istvan Novak On 1/30/2018 12:06 PM, Douglas Smith wrote: > I did that experiment a long time ago, almost 30 years ago, when > developing this experiment, which is described in my book. > > Reducing ground lead length to near zero eliminates the effect almost > completely

Re: [PSES] EMC tests called up in Safety standards

One common cause of nuisance tripping is EMI line filters whose input capacitance to ground biases GFCIs near the tripping point. I would never power up a computer on a GFCI circuit, asking for trouble. No high voltage pulses needed. Doug Smith Sent from my iPhone IPhone: 408-858-4528 Office:

Re: [PSES] [SI-LIST] Re: Measurement Dilema - THE EXPLANATION!

Hi Istvan, If I connect the oscillator directly to the scope chassis, I get similar readings at different frequencies. I generally get less amplitude as well. The small capacitance between the scope and oscillator is capable of tuning the whole system to a low input impedance on the probe end.

[PSES] Looking for Jeffery Silverberg

I am looking to contact Jeffery as I think his Facebook Messenger account has been compromised in a really bad way. Can anyone give me his real contact info? Doug Smith Sent from my iPhone IPhone: 408-858-4528 Office: 702-570-6108 Email: d...@dsmith.org Website: http://dsmith.org -

Re: [PSES] Measurement dilema

Not really. Full disclosure tomorrow when I get settled in the office. It is actually simpler than one might imagine, just will take me a fair amount of typing so need a real keyboard not an iPhone. Doug Smith Sent from my iPhone IPhone: 408-858-4528 Office: 702-570-6108 Email: d...@dsmith.org

Re: [PSES] [SI-LIST] Youtube channel

Not sure what the problem is. Maybe a Windoz setup problem? 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 28, 2018 at 13:48, Lyndell Asbenson wrote: Doug, Thanks for your

Re: [PSES] Measurement dilema

I was thinking only that people who have had my course not reply because they should already know. Will post the answer discussion later tomorrow. I have really enjoyed the replies and learned from them. And you are right. Ground lead parasitic inductance plays a major part. Doug Smith Sent

Re: [PSES] Measurement dilema

Great quote! It pretty much describes much of medical research in my opinion. The great thing about engineering is the field is “grounded” (pun intended) in fundamentals. No so much in medicine where money and politics matter as much as science. My hobby when I am not doing engineering is

Re: [PSES] Measurement dilema

That is certainly true, but the problem here is there is an error one is not aware of, although this is an extreme example. Doug Smith Sent from my iPhone IPhone: 408-858-4528 Office: 702-570-6108 Email: d...@dsmith.org Website: http://dsmith.org On Fri, Jan 26, 2018 at 17:34, Richard Nute

Re: [PSES] ESD question

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

Re: [PSES] ESD question

o on J Then, of course, there may be attempted legal action – which, is, I guess, a minefield against which to defend if you are the manufacturer /supplier! John E Allen W.London, UK. From: Douglas Smith [mailto:d...@emcesd.com] Sent: 06 January 2018 18:28 To: EMC-PSTC@LISTSERV.IEEE.ORG Subje

Re: [PSES] ESD question

d idea for a new experiment at your workshops. ;-) Cheers, Adam in Atlanta On Sat, Jan 6, 2018 at 2:48 AM, Douglas Smith < d...@emcesd.com [d...@emcesd.com] > wrote: Thus is a common occurrence. The iPhone was not actually connected to you so the large E field induced a different charge on

Re: [PSES] ESD question

BTW, indoor humidity is constant in Boulder City, NV as the dewpoint does not change much summer to winter. It is often 10 degrees F almost any time of year, and conventional air conditioning actually increases indoor relative humidity as they do not remove water (dewpoint too low) but cool the

Re: [PSES] ESD question

Thus is a common occurrence. The iPhone was not actually connected to you so the large E field induced a different charge on you than on the phone and hence the discharge through your ear (the lowest breakdown between the iPhond and you. Such discharges have led to claims of injury that ended up

[PSES] Uncertainty in ESD testing

I recently replied to another post and mentioned uncertainty in ESD testing. I thought it would be good to post it separately to start a wider discussion, so here we go: In ESD testing, the poor specification of the simulator in standards, like IEC 61000-4-2 [tel:61000-4-2] , leads to

Re: [PSES] God EMC practice

How would you relate the tolerance of placement of system components like cables or PCs (in cm) to measurement uncertainty? Just setting up for the next test can make a few dB difference. In a large system, it may even affect antenna placement in the chamber to get the right distance to the

Re: [PSES] Flicker from LED and CFL light bulbs

Hi Ken and the group, The LED bulbs I have, mostly Cree and high quality, take about a second to extinguish completely after power is removed, about the same as an incandescent bulb, obviously there is energy storage in the bulb. I am surprised the Brits are affected by 100 Hz flicker. I could

Re: [PSES] [SPAM] RE: [PSES] EU's new approach directive transitions

I agree with John. Also a search for FMEA produces a lot of references to some music organizations and others. Only if directed to a very narrow audience (not this group!) where everyone knows what is being referenced, should one expect others to spend a total of hours looking up acronyms that

Re: [PSES] SV: [PSES] Fwd: [PSES] Current probe for CM currents

Pretty much everything by Gert looks incorrect or possibly a some typos. More turns on the core gives you less output over most of the frequency range but more output at the very low end of the frequency. Zt = M/L * Zo in the flat region of the frequency response where Zo is the 50 Ohm load on

Re: [PSES] Conducted RF injected on Ethernet cable ... fails

Dan is correct, but first make sure the lab did the test correctly, most do not in my experience leading to often a 6 dB over test. When I have pointed this out to test labs during testing, they always correct their testing when shown the paragraph about the current limit. After the test is run

Re: [PSES] Conducted RF injected on Ethernet cable ... fails

Your option #2 may kill the Ethernet signal unless the beads are 4 or more terminal common mode ones. Doug Smith Sent from my iPhone IPhone: 408-858-4528 [tel:408-858-4528] Office: 702-570-6108 [tel:702-570-6108] Email: d...@dsmith.org Website: http://dsmith.org On Thu, Dec 10, 2015 at 01:26,

Re: [PSES] Conducted RF injected on Ethernet cable ... fails

How much did it fail by? You need to know this. This test is often done in error by test labs resulting in a 6 dB over test. Make sure they are applying the current limit loophole that is allowed for many cases, often for Ethernet cables. Be sure the failure is in your equipment not the aux

[PSES] Repeat free presentation on EMC Lab test errors

Hi All, I will be doing a repeat session on my EMC Test Lab Errors presentation for those who missed the first one, next Wednesday, 27th June at 0930 PDT. Here is the description: Measurement and procedural errors at EMC (and other) test labs can cost your company a lot! Some of the errors

[PSES] Free presentation on EMC test lab errors

Hi All, Measurement and procedural errors at EMC (and other) test labs can cost your company a lot! Some of the errors are egregious and others (more common ones) are worth a few dB to 6 dB typically. These are easy to spot by anyone viewing the test (no special training needed) so I wonder

[PSES] video viewing problems with Mozilla

Hi All, Over the weekend I uploaded a lot of technical podcasts and some videos to my website. The link is: http://emcesd.com/#Podcasts Some of the videos will not play on Mozilla products but work on IE, Safari, and Opera. You can also right click and save on your computer to play with

[PSES] free technical podcasts added

Hi All, I have added many technical podcasts to my site http://emcesd.com. The description and link to the podcasts is just below the University of Oxford material on the site or you can use this link to go directly to that part of the page: http://emcesd.com/#Podcasts There are many

Re: [PSES] Interference Caused by Microwave Oven

Hi Ken, I suspect that the health impact of the microwave popcorn far exceed the leakage from the oven. This stuff is bad, not fit for human consumption. Doug Douglas C. Smith University of Oxford Tutor Department for Continuing Education Oxford,

Re: [PSES] OSM decision

Hi Rich and the group, Even DC power internal busses in equipment are likely to have 1000 Volt transients if hot plug of power supplies and/or loads are allowed. Outside transients are not necessary to have this happen. I have personally observed these EFT

Re: [PSES] Brick power supplies and test errors (two topics)

Hi Ed and the Group, Ed said: "Did you create a write-up on what those errors specifically were, and how it happened that you noticed them in time to control them?" I have not specifically written them up although I do tell them as war

Re: [PSES] electronic design related postings on Twitter

-- On 10/9/14 8:48 PM, Douglas Smith wrote: Hi Everyone, I am going to try sending short "tweets" on electronic design and troubleshooting you may be interested in. If you want to see them, look at: @dougcsmith_ee on Twitter. It

[PSES] electronic design related postings on Twitter

Hi Everyone, I am going to try sending short "tweets" on electronic design and troubleshooting you may be interested in. If you want to see them, look at: @dougcsmith_ee on Twitter. It it proves useful to people I may permanently keep doing it. Just did a

[PSES] retry, links to new video on PCB troubleshooting with RF injection

Hi All, Got an error message from my last post so not sure who may have received it, so here is a retry: I just uploaded my latest video to YouTube on PCB design troubleshooting and finding possible radiated immunity problems using direct RF injection. Here is the link to the video. The

[PSES] new video posted to youtube on ESD generated EMI

Hi All, A few days ago I posted a link to my new video on my website. I have also posted it to youtube. The data rate is better from youtube. The subject is comparing the intensity of ESD directly from human skin to ESD from a piece of metal held in a hand as seen in the EMI generated by

[PSES] Link correction for video

Hi All, Not sure how the link got changed to youtu.be in my last post although it seems to work. The intended link is: https://www.youtube.com/watch?v=4LzLbOUYT-I Doug -- University of Oxford Tutor Department for Continuing Education Oxford, Oxfordshire, United Kingdom

[PSES] Comparing HMM and HBM ESD though its radiated EMI

Hi Everyone, I just posted my September Technical Tidbit titled: Human Metal Model ESD Compared to Direct Skin Discharge (Human Body Model) ESD (Revisited in Video Format) This article is really a video of the live experiment, my first video Technical Tidbit. The video is in flash but if

[PSES] radiated emissions testing may understate actual emissions, an example using a class D stereo amp

Hi Everyone, I just posted my latest Technical Tidbit a few hours ago using a class D stereo amplifier to illustrate a potential problem whereby emission test standards may understate the emissions from a digital device. Here goes: Abstract: Radiated

[PSES] question about overheated/swollen UPS batteries

Hi Everyone, I seem to have a continuing experience with UPS equipment overheating the batteries. Most all of my UPSs have done this at one time or another. Here is an example: At the office, I was to be away for a week and if the power went out, some of my UPSs sound an alarm which can

Re: [PSES] [JunkMail] [PSES] Inexpensive RF generator

Hi Ken and the group, Sounds like a very nice generator. I wish it could be controlled from a web browser for a universal interface, like many scopes these days. My productivity is so much higher on a Mac compared to Windows, that a Windows machine is to

Re: [PSES] test setup for table top ungrounded equipment 61000-4-2 IEC:2008 figure 6 page 20

I don't think 1 or 2 MOhms will make much difference for one second application of ESD pulses. Tc = RC = 10**6 x 100*10**-12 = 10**-4 seconds (100 pF estimated, not calculated between HCP and GRP. Even 10X that capacitance would still yield a Tc of 1 ms,

Re: [PSES] Looking fro New Opportuinity

I can vouch for Don. He is a great engineer and is very knowledgeable. Very good background in engineering fundamentals and inquisitive mind. I have had the pleasure of having him attend one of my seminars. Doug On 11/15/12 6:07 AM, Don MacArthur

[PSES] Novel transmission line equivalent circuit

Hi Everyone, This month my Technical Tidbit is written by Tim Maloney of Intel for publication on my site. He has devised a very good transmission line equivalent circuit than makes it easy to understand transmission line impedance behavior as a function of line length and termination

A method of avoiding ESD problems

Hi All, My Technical Tidbit article for this month discusses avoiding ESD events when system modules or connectors make contact by using static dissipative materials in plastic parts, a technique normally used to reduce static charge in factory environments. Minimizing ESD Events Involving

Shielded loop parasitic coupling

Hi Everyone, I have posted the latest Technical Tidbit on my website http://www.dsmith.org . It should be interesting to EMC folks who use magnetic field probes and to SI people as well since magnetic loops are very useful at finding board layout issues by signal injection thorough mutual

[Fwd: Shielded loop parasitic coupling] the missing link

Date: Wed, 04 Jun 2008 19:39:59 -0700 From: Douglas Smith d...@emcesd.com mailto:d...@emcesd.com Reply-To: d...@dsmith.org Organization: D. C. Smith Consultants To: emc-pstc emc-p...@ieee.org mailto:emc-p...@ieee.org , SI-List si-l...@freelists.org mailto:si-l

Re: Fixes

Hi Lisa and the group, I am on a business trip at the moment, but lucky enough to be at a hotel with high speed internet service. Lisa, I guess you could start with my website at http://emcesd.com where I have posted about 60 papers and articles, many of them on fixing EMI problems. There

Re: grounding schemes EMI

Hi David (and the group), Take a look at the Technical Tidbits section of my site at http://emcesd.com where you will find some experimental evidence for your viewpoint. This month's article (at the bottom of the main page) presents some data and links to two other articles. Doug On