RE: [JunkMail] 1500 ohms 100 pF gun?
Hey! We never discharged the EUT after the event. Rev Dr E From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 3:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: [JunkMail] 1500 ohms 100 pF gun?
This is turning into a GREAT thread! Cortland Richmond KA5S - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: [JunkMail] 1500 ohms 100 pF gun?
Dang it! Me too!! Best Regards Charles Grasso Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: 3032042...@vext.com Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org From: Conway, Patrick R (Houston) [mailto:p.con...@hp.com] Sent: Friday, June 23, 2006 10:23 AM To: Grasso, Charles; Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Good question. Two data points: Heaviside and Einstein. Both were unconventional in their thinking. Both were initially received with skepticism. But both were right. However, Heaviside was brilliant when young, but quite the crack-pot when he got older. Also, Einstein's major contributions were all out in public by the time he was 30 yrs old. So, the conclusion I draw is that yes, unconventional thinkers are right, but only when they are young. Rats. Too late for me!! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: Friday, June 23, 2006 3:55 AM To: Conway, Patrick R (Houston); Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? So - does that mean that only unconventional engineers are right?? :-) Best Regards Charles Grasso Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: 3032042...@vext.com Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 1:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? I wonder if Michael would explain how the discharge energy gets back >from the equipment being zapped to the source. It seems very mysterious. Actually, not mysterious at all. But does require some thinking outside of what is considered "normal" current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a batter
RE: [JunkMail] 1500 ohms 100 pF gun?
And you can also try "spreading inductance" - those units are in henries/square...!! Best Regards Charles Grasso Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: 3032042...@vext.com Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Shinn, John Sent: Friday, June 23, 2006 11:22 AM To: Conway, Patrick R (Houston); Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? I love the "ohms per square" term. It drives the non-EE nuts. John Shinn, P.E. From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Friday, June 23, 2006 9:22 AM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? If the clear, logical explanation does not work, then try my fall-back plan: If it is an ME try this: "Oh, think of ESD as the electrical equivalent to the study of thermal gradients in non-homogeneous stratified media". (or pick another incomprehensible subject in their area of expertise- but you gotta do it with a straight face!!) My favorite story about the EE / ME rift is about units. I know more than a few ME's who just cringe when they hear the term from shielding: "Ohms per square". They are left hanging, waiting for you to complete the sentence. "Ohms per square... WHAT?" they ask. They just can't conceive a system of measurement that has a variable in the units! Can't help but find humor in that. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:58 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Thank you Sir, I have toughest time of my career explaining this to my co-workers (Mechanical engineers: I apologize for If unknowing I will hurt the feeling of any mechanical engineer) who possess mysterious thinking about ESD. Sudhakar Wasnik From: Conway, Patrick R (Houston) [mailto:p.con...@hp.com] Sent: Thursday, June 22, 2006 12:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patric
RE: [JunkMail] 1500 ohms 100 pF gun?
I love the "ohms per square" term. It drives the non-EE nuts. John Shinn, P.E. From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Friday, June 23, 2006 9:22 AM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? If the clear, logical explanation does not work, then try my fall-back plan: If it is an ME try this: "Oh, think of ESD as the electrical equivalent to the study of thermal gradients in non-homogeneous stratified media". (or pick another incomprehensible subject in their area of expertise- but you gotta do it with a straight face!!) My favorite story about the EE / ME rift is about units. I know more than a few ME's who just cringe when they hear the term from shielding: "Ohms per square". They are left hanging, waiting for you to complete the sentence. "Ohms per square... WHAT?" they ask. They just can't conceive a system of measurement that has a variable in the units! Can't help but find humor in that. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:58 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Thank you Sir, I have toughest time of my career explaining this to my co-workers (Mechanical engineers: I apologize for If unknowing I will hurt the feeling of any mechanical engineer) who possess mysterious thinking about ESD. Sudhakar Wasnik From: Conway, Patrick R (Houston) [mailto:p.con...@hp.com] Sent: Thursday, June 22, 2006 12:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? I wonder if Michael would explain how the discharge energy gets back >from the equipment being zapped to the source. It seems very mysterious. Actually, not mysterious at all. But does require some thinking outside of what is considered "normal" current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For thi
Re: [JunkMail] 1500 ohms 100 pF gun?
I think it is more than coincidence that the two examples cited were not really engineers, but scientists. Brilliant scientists tend to crest early, whereas good engineers, like fine wine, just get better. But the coincidence I see is between the examples of scientists and the science of ESD. Just the fact that there have been so many waveforms and so many refinements to the test procedure lead me to the conclusion that ESD is a science, it is not mature enough to be termed an engineering discipline. > From: "Conway, Patrick R (Houston)" > Date: Fri, 23 Jun 2006 11:22:33 -0500 > To: "Grasso, Charles" , "Sudhakar Wasnik" > , "John Woodgate" , > > Subject: RE: [JunkMail] 1500 ohms 100 pF gun? > > Good question. > Two data points: Heaviside and Einstein. > Both were unconventional in their thinking. > Both were initially received with skepticism. > But both were right. > However, Heaviside was brilliant when young, but quite the crack-pot when he > got older. > Also, Einstein's major contributions were all out in public by the time he was > 30 yrs old. > > So, the conclusion I draw is that yes, unconventional thinkers are right, but > only when they are young. > > Rats. Too late for me!! > > > Best Regards, > Patrick Conway, NCE. > > 281.514.2259 > 281.524.5473 (fax) > p.con...@hp.com > > -Original Message- > From: Grasso, Charles [mailto:charles.gra...@echostar.com] > Sent: Friday, June 23, 2006 3:55 AM > To: Conway, Patrick R (Houston); Sudhakar Wasnik; John Woodgate; > emc-p...@ieee.org > Subject: RE: [JunkMail] 1500 ohms 100 pF gun? > > So - does that mean that only unconventional engineers are right?? :-) > > Best Regards > Charles Grasso > Compliance Engineer > Echostar Communications Corp. > Tel: 303-706-5467 > Fax: 303-799-6222 > Cell: 303-204-2974 > Pager/Short Message: 3032042...@vext.com > Email: charles.gra...@echostar.com; > Email Alternate: chasgra...@ieee.org > > -Original Message- > From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, > Patrick R (Houston) > Sent: Thursday, June 22, 2006 1:47 PM > To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org > Subject: RE: [JunkMail] 1500 ohms 100 pF gun? > > Ah, ha. > > Glad to find another engineer who thinks like I do - unconventional! > > anecdote- > One time I visited a large, well respected IT company who was having an ESD > problem with a new product. > They could not release to production because they could not pass the ESD test. > I made one change to their test procedure and they were able to pass. > Nothing spectacular really, just a little applied unconventional thinking! > I observed that their test engineer was doing the test and then discharging > the EUT after each strike (battery operated EUT). > The EUT passed each and every strike, but had an upset during his connection > of the discharge wire. > The discharge wire had no resistors in line. > It was a straight dump to the horizontal coupling plane. > > I explained to the team, showed them the failures were only during post-test > charge dump. > I explained that the discharge event is uncontrolled. > It could have more ore less rise time, more or less fall time, more or less > peak amplitude. > It is uncontrolled. > If they wanted to test with that waveform- no problem. > But it is not required for CE Mark (their target). > Everyone was happy! > Much rejoicing. > > Anyway- clear evidence that even the post-test discharge needs to be done > correctly. > And, evidence that more training is always a good thing! > > > Best Regards, > Patrick Conway, NCE. > > 281.514.2259 > 281.524.5473 (fax) > p.con...@hp.com > > -Original Message- > From: Sudhakar Wasnik [mailto:swas...@sandisk.com] > Sent: Friday, June 23, 2006 3:14 AM > To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org > Subject: RE: [JunkMail] 1500 ohms 100 pF gun? > > You are correct sir, > > The current flow is from higher potential to lower potential. > So with repetitive zaps, the system accumulates the charge (potential) higher > than Gun potential, So current will flow from Object being zapped to the Gun > (Source). > That's why standard requires removing the unspent charge from the EUT by > manual discharge before applying next zap. > > If we consider this is same as lightening event, Then John is correct. > It is mysterious even to think that the earth (Load) (earth) will pump current > in to Clouds (Source) during repetitive lightening strikes. > > Sudhakar Wasnik > > Phone. : 408-542-2928 > > -Original Message- &g
RE: [JunkMail] 1500 ohms 100 pF gun?
Good question. Two data points: Heaviside and Einstein. Both were unconventional in their thinking. Both were initially received with skepticism. But both were right. However, Heaviside was brilliant when young, but quite the crack-pot when he got older. Also, Einstein's major contributions were all out in public by the time he was 30 yrs old. So, the conclusion I draw is that yes, unconventional thinkers are right, but only when they are young. Rats. Too late for me!! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: Friday, June 23, 2006 3:55 AM To: Conway, Patrick R (Houston); Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? So - does that mean that only unconventional engineers are right?? :-) Best Regards Charles Grasso Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: 3032042...@vext.com Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 1:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? I wonder if Michael would explain how the discharge energy gets back from the equipment being zapped to the source. It seems very mysterious. Actually, not mysterious at all. But does require some thinking outside of what is considered "normal" current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller "pop" sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you
RE: [JunkMail] 1500 ohms 100 pF gun?
If the clear, logical explanation does not work, then try my fall-back plan: If it is an ME try this: "Oh, think of ESD as the electrical equivalent to the study of thermal gradients in non-homogeneous stratified media". (or pick another incomprehensible subject in their area of expertise- but you gotta do it with a straight face!!) My favorite story about the EE / ME rift is about units. I know more than a few ME's who just cringe when they hear the term from shielding: "Ohms per square". They are left hanging, waiting for you to complete the sentence. "Ohms per square... WHAT?" they ask. They just can't conceive a system of measurement that has a variable in the units! Can't help but find humor in that. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:58 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Thank you Sir, I have toughest time of my career explaining this to my co-workers (Mechanical engineers: I apologize for If unknowing I will hurt the feeling of any mechanical engineer) who possess mysterious thinking about ESD. Sudhakar Wasnik From: Conway, Patrick R (Houston) [mailto:p.con...@hp.com] Sent: Thursday, June 22, 2006 12:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? I wonder if Michael would explain how the discharge energy gets back from the equipment being zapped to the source. It seems very mysterious. Actually, not mysterious at all. But does require some thinking outside of what is considered "normal" current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the devi
RE: [JunkMail] 1500 ohms 100 pF gun?
Thank you Sir, I have toughest time of my career explaining this to my co-workers (Mechanical engineers: I apologize for If unknowing I will hurt the feeling of any mechanical engineer) who possess mysterious thinking about ESD. Sudhakar Wasnik From: Conway, Patrick R (Houston) [mailto:p.con...@hp.com] Sent: Thursday, June 22, 2006 12:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? I wonder if Michael would explain how the discharge energy gets back >from the equipment being zapped to the source. It seems very mysterious. Actually, not mysterious at all. But does require some thinking outside of what is considered "normal" current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller "pop" sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what was the "Return path", since the EUT cord was removed? Why is it that the simulator no longer discharges? Those last two questions have the same answer. Maybe the normal loop model, "source-destination-return-to-source", does not apply? Hmm. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell m
RE: [JunkMail] 1500 ohms 100 pF gun?
Charles, It is not a question of right or wrong. It is about having logical rational explanation. Sudhakar From: Grasso, Charles [mailto:charles.gra...@echostar.com] Sent: Thursday, June 22, 2006 12:55 PM To: Conway, Patrick R (Houston); Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? So - does that mean that only unconventional engineers are right?? :-) Best Regards Charles Grasso Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: 3032042...@vext.com Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 1:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? I wonder if Michael would explain how the discharge energy gets back >from the equipment being zapped to the source. It seems very mysterious. Actually, not mysterious at all. But does require some thinking outside of what is considered "normal" current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller "pop" sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what was the "Return path", since the EUT cord was removed? Why is it that the simulator no longer discharges? Those last two questions have the same answer. Maybe the normal loop model, "source-destination-return-to-source", does not apply? Hmm. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - Thi
RE: [JunkMail] 1500 ohms 100 pF gun?
So - does that mean that only unconventional engineers are right?? :-) Best Regards Charles Grasso Compliance Engineer Echostar Communications Corp. Tel: 303-706-5467 Fax: 303-799-6222 Cell: 303-204-2974 Pager/Short Message: 3032042...@vext.com Email: charles.gra...@echostar.com; Email Alternate: chasgra...@ieee.org From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 1:47 PM To: Sudhakar Wasnik; John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? I wonder if Michael would explain how the discharge energy gets back >from the equipment being zapped to the source. It seems very mysterious. Actually, not mysterious at all. But does require some thinking outside of what is considered "normal" current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller "pop" sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what was the "Return path", since the EUT cord was removed? Why is it that the simulator no longer discharges? Those last two questions have the same answer. Maybe the normal loop model, "source-destination-return-to-source", does not apply? Hmm. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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 li
RE: [JunkMail] 1500 ohms 100 pF gun?
Ah, ha. Glad to find another engineer who thinks like I do - unconventional! anecdote- One time I visited a large, well respected IT company who was having an ESD problem with a new product. They could not release to production because they could not pass the ESD test. I made one change to their test procedure and they were able to pass. Nothing spectacular really, just a little applied unconventional thinking! I observed that their test engineer was doing the test and then discharging the EUT after each strike (battery operated EUT). The EUT passed each and every strike, but had an upset during his connection of the discharge wire. The discharge wire had no resistors in line. It was a straight dump to the horizontal coupling plane. I explained to the team, showed them the failures were only during post-test charge dump. I explained that the discharge event is uncontrolled. It could have more ore less rise time, more or less fall time, more or less peak amplitude. It is uncontrolled. If they wanted to test with that waveform- no problem. But it is not required for CE Mark (their target). Everyone was happy! Much rejoicing. Anyway- clear evidence that even the post-test discharge needs to be done correctly. And, evidence that more training is always a good thing! Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com From: Sudhakar Wasnik [mailto:swas...@sandisk.com] Sent: Friday, June 23, 2006 3:14 AM To: Conway, Patrick R (Houston); John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? I wonder if Michael would explain how the discharge energy gets back from the equipment being zapped to the source. It seems very mysterious. Actually, not mysterious at all. But does require some thinking outside of what is considered "normal" current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller "pop" sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what was the "Return path", since the EUT cord was removed? Why is it that the simulator no longer discharges? Those last two questions have the same answer. Maybe the normal loop model, "source-destination-return-to-source", does not apply? Hmm. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send you
RE: [JunkMail] 1500 ohms 100 pF gun?
You are correct sir, The current flow is from higher potential to lower potential. So with repetitive zaps, the system accumulates the charge (potential) higher than Gun potential, So current will flow from Object being zapped to the Gun (Source). That's why standard requires removing the unspent charge from the EUT by manual discharge before applying next zap. If we consider this is same as lightening event, Then John is correct. It is mysterious even to think that the earth (Load) (earth) will pump current in to Clouds (Source) during repetitive lightening strikes. Sudhakar Wasnik Phone. : 408-542-2928 From: emc-p...@ieee.org [mailto:emc-p...@ieee.org] On Behalf Of Conway, Patrick R (Houston) Sent: Thursday, June 22, 2006 11:15 AM To: John Woodgate; emc-p...@ieee.org Subject: RE: [JunkMail] 1500 ohms 100 pF gun? I wonder if Michael would explain how the discharge energy gets back >from the equipment being zapped to the source. It seems very mysterious. Actually, not mysterious at all. But does require some thinking outside of what is considered "normal" current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller "pop" sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what was the "Return path", since the EUT cord was removed? Why is it that the simulator no longer discharges? Those last two questions have the same answer. Maybe the normal loop model, "source-destination-return-to-source", does not apply? Hmm. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
RE: [JunkMail] 1500 ohms 100 pF gun?
I wonder if Michael would explain how the discharge energy gets back from the equipment being zapped to the source. It seems very mysterious. Actually, not mysterious at all. But does require some thinking outside of what is considered "normal" current flow. A simple experiment (real or just a thought experiment) can show the answer. Try this experiment- run a normal ESD test for table top equipment. For this, doesn't matter what test standard. Must use a battery operated EUT. Make sure the EUT power cord is disconnected. Now discharge the ESD simulator to the EUT one time. Discharge works fine, no observable variance in the ESD. But, continue to zap the device. Notice that the observable characteristics of the ESD pulses become less severe. Smaller "pop" sound, plus the simulator tip has to get closer to the device to discharge. Eventually, you can no longer discharge to the EUT. So, what was happening? For all of those discharges what was the "Return path", since the EUT cord was removed? Why is it that the simulator no longer discharges? Those last two questions have the same answer. Maybe the normal loop model, "source-destination-return-to-source", does not apply? Hmm. Best Regards, Patrick Conway, NCE. 281.514.2259 281.524.5473 (fax) p.con...@hp.com - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: [JunkMail] 1500 ohms 100 pF gun?
In message <449ab954.1060...@emcesd.com>, dated Thu, 22 Jun 2006, Doug Smith writes >Michael tried to respond but not being a member of the list, his reply >bounced. I have forwarded it below. I wonder if Michael would explain how the discharge energy gets back >from the equipment being zapped to the source. It seems very mysterious. -- OOO - Own Opinions Only. Try www.jmwa.demon.co.uk and www.isce.org.uk 2006 is YMMVI- Your mileage may vary immensely. John Woodgate, J M Woodgate and Associates, Rayleigh, Essex UK - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
Re: [JunkMail] 1500 ohms 100 pF gun?
Hi All, Michael tried to respond but not being a member of the list, his reply bounced. I have forwarded it below. Doug From Michael King: >Greetings, >When we (David Reynolds, Andy Hish and myself) determined the >waveforms of ESD, we researched several "typical" applications: Human >finger-tip direct; Humans with small metallic intervening objects >(e.g. keys, coins, pens); and, Humans with large mobile furnishings >(e.g. chairs and push carts). > >Our intention was to present the concept that probes that would >replicate these events, would be applied to products where the >specific type of contact would be prevalent. Keyboards, for example, >would be typical of "finger-tip" events; areas with supervisor locks >requiring keys (such as on POS terminals) would receive the >humans-metal-object events; and some regions where a cart (e.g. >grocery cart) would be tested with that much higher current replication. > >As is universally recognized today, we discovered that there were two >essential characteristics to the ESD event: an "early event" with a >very low source impedance; and, a "trailing event" with a higher >impedance. (I'm using the terms we had in our private discussions >together circa 1979.) > >The early event for human finger-tip direct has a typical source >impedance of about 200 Ohms, with the trailing event having a total >source impedance of about 1,200 Ohms. > >The early event for humans with a small metallic object is about 20 >Ohms with the trailing event about 420 Ohms. > >Desk chairs and push carts tend to exhibit source impedances in the >early event of about 10 Ohms, and for the whole of the event about 50 >to 75 Ohms. > >So, Andy Hish who was successful in producing a test generator that >essentially replicated these events even as they shifted waveforms at >various ESD amplitudes (I have the historical data) decided to assign >probes for his ESD-255 as: > >P-255-0 for the finger tip event; > >P-255-1 for the human/metal object event; and, > >P-255-3 for the "furnishings" event. > >When we revealed our results to various corporations circa 1980, the >landslide of interest from management was only for the P-255-1 probe, >with a few having interest also in the P-255-3 probe. To the best of >my knowledge, only ONE P-255-0 probe was ever produced, and that one >was the full-build prototype that we used to verify that the >replication for that condition could be achieved. That probe was lost >to history decades ago. > >We later collaborated with Peter Richman, then V-P of engineering and >founder of KeyTek, and he had assigned various DN numbers for probes >of his "true ESD" K2020 (by memory) test set. The DN-10, I seem to >remember, was for the human metal/object probe, and although he knew >of our numbers for the finger tip probe, to the best of my knowledge >as was in the case with Andy Hish, no one ever ordered the >"finger-tip" equivalent probe from him as well. > >BTW, the construction of the "finger-tip" probe is quite tricky >because of the distribution of the "distributed capacitance field >source" for the "early event". While it was possible to adapt Andy >Hish's P-255-1 probe (by Andy's internal processes) to the ~3x higher >resistance numbers that were in the multiple element distributed line >(that looked like a probe externally), the 200 Ohms "early event" we >found could only be replicated by something like a resistively lossy, >graphite impregnated, hemisphere at the "tip" of the probe, >presenting a diameter of about 5cm on the major axis and the depth of >about 2cm on the minor axis, with the graphite saturation set to >about 200 to 300 Ohms/square when measured on the surface. > >Michael > >At 06:11 PM 6/21/2006, Doug Smith wrote: >>Hi Cortland and the group (from vacation in Orange County, CA), >> >>I remember using such a network in a home built ESD simulator many >>years ago at Bell Labs, a human "finger" model. Electronic >>telephones that had no problem with such a simulator did not come >>back for warrantee repairs. The IEC network, which models a piece of >>metal in the hand, is much more severe and is often an overtest of >>small plastic items like telephones and PDAs. >> >>I have copied Michael King on this. He is an early pioneer in ESD >>and perhaps can shed some light on this in addition to what I have >>said above. Much of what we now do in ESD was laid out by Michael >>decades ago and is still valid. >> >>Doug >> >>Cortland Richmond wrote: >>>Was looking for one for some military testing at work. I seem to recall >>>that the Andy Hish ESD-255 used this network in one of its probes. Am I >>>wrong? >>> >>>Cortland Richmond >>>KA5S >>>- >>> >>>This message is from the IEEE Product Safety Engineering Society >>>emc-pstc discussion list.Website: http://www.ieee-pses.org/ >>>To post a message to the list, send your e-mail to emc-p...@ieee.org >>>Instructions: http://listserv.ieee.org/r
Re: [JunkMail] 1500 ohms 100 pF gun?
Hi Cortland and the group (from vacation in Orange County, CA), I remember using such a network in a home built ESD simulator many years ago at Bell Labs, a human "finger" model. Electronic telephones that had no problem with such a simulator did not come back for warrantee repairs. The IEC network, which models a piece of metal in the hand, is much more severe and is often an overtest of small plastic items like telephones and PDAs. I have copied Michael King on this. He is an early pioneer in ESD and perhaps can shed some light on this in addition to what I have said above. Much of what we now do in ESD was laid out by Michael decades ago and is still valid. Doug Cortland Richmond wrote: > Was looking for one for some military testing at work. I seem to recall > that the Andy Hish ESD-255 used this network in one of its probes. Am I > wrong? > > > Cortland Richmond > KA5S > > - > > This message is from the IEEE Product Safety Engineering Society > emc-pstc discussion list.Website: http://www.ieee-pses.org/ > > To post a message to the list, send your e-mail to emc-p...@ieee.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 emcp...@ptcnh.net > Mike Cantwell mcantw...@ieee.org > > For policy questions, send mail to: > > Jim Bacher: j.bac...@ieee.org > David Heald:emc-p...@daveheald.com > > All emc-pstc postings are archived and searchable on the web at: > > http://www.ieeecommunities.org/emc-pstc > > -- ___ _Doug Smith \ / ) P.O. Box 1457 = Los Gatos, CA 95031-1457 _ / \ / \ _TEL/FAX: 408-356-4186/358-3799 / /\ \ ] / /\ \ Mobile: 408-858-4528 | q-( ) | o | Email: d...@dsmith.org \ _ /]\ _ / Web: http://www.dsmith.org - This message is from the IEEE Product Safety Engineering Society emc-pstc discussion list.Website: http://www.ieee-pses.org/ To post a message to the list, send your e-mail to emc-p...@ieee.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 emcp...@ptcnh.net Mike Cantwell mcantw...@ieee.org For policy questions, send mail to: Jim Bacher: j.bac...@ieee.org David Heald:emc-p...@daveheald.com All emc-pstc postings are archived and searchable on the web at: http://www.ieeecommunities.org/emc-pstc
