ESD sensitive devices can have a charge induced on them when moving near a charged object if they are not grounded or in a static shielding bag/faraday cage. The charge is dangerous in that the part now discharges when contacted by a grounded object/person - depending on the rate of discharge (ex. dissipative workbench vs. conductive tool or surface) damage may occur. Mike |---------+------------------------------> | | "Blair K. Hogg" | | | <blair.k.hogg@GAI-T| | | RONICS.COM> | | | Sent by: TechNet | | | <[log in to unmask]> | | | | | | | | | 05/06/2005 02:46 PM| | | Please respond to | | | TechNet E-Mail | | | Forum; Please | | | respond to "Blair | | | K. Hogg" | | | | |---------+------------------------------> >--------------------------------------------------------------------------------------------------------------| | | | To: [log in to unmask] | | cc: | | Subject: Re: [TN] FW: Static and break over voltage spacing standards? | >--------------------------------------------------------------------------------------------------------------| I was under the impression that sensitive devices could be harmed by a close electric charge, that it didn't have to make a jump, due to the effects of the electric field. Could be I was mistaken. Can the plastic panels be coated with a topical antistatic compound? Blair >>> [log in to unmask] 05/06/05 03:23PM >>> Hey, where are the ESD gurus? Can't static electricity go to 30K or 40KV? That is going to need a much bigger gap. How about a section of copper window screen that is grounded? -----Original Message----- From: TechNet [mailto:[log in to unmask]] On Behalf Of Dehoyos, Ramon Sent: Friday, May 06, 2005 3:16 PM To: [log in to unmask] Subject: Re: [TN] FW: Static and break over voltage spacing standards? From a previous life I was taught that a see level a 10KV will jump 1 inch. The higher the elevation the longer the distance that will arc to due to less air or less impediment. But I have seen articles published that say that is less than 1 inch for 10 KV. Regards, Ramon -----Original Message----- From: TechNet [mailto:[log in to unmask]]On Behalf Of Brooks,Bill Sent: Friday, May 06, 2005 11:07 AM To: [log in to unmask] Subject: [TN] FW: Static and break over voltage spacing standards? I hope that someone on the forum may have a comment or two about this subject... and can help John. - Bill -----Original Message----- From: John Smith [mailto:[log in to unmask]] Sent: Thursday, May 05, 2005 7:21 AM To: 'Bill Brooks' Subject: RE: Web site question Thank you for your response Bill, I am trying find out at what voltage and at what distance I need to be concerned about a static discharge from a plastic surface. I have a silicon wafer processing tool and there is concern about static discharge from the exterior plastic panels. I want to be able to determine, the voltage vs.. distance safe point, i.e. (at 500v of charge an arc will not jump at a greater distance than .5") I understand that the type of material, the humidity and other factors make a difference, but there must be some test data some where that points to some generalities. Thanks again for your time bill John -----Original Message----- From: Bill Brooks [mailto:[log in to unmask]] Sent: Wednesday, May 04, 2005 11:03 PM To: 'John Smith' Subject: RE: Web site question http://sprott.physics.wisc.edu/demobook/chapter4.htm see table 4.2 The issue with predicting electrical arcing is in defining the environmental conditions that contribute to the 'break over' voltage. The presence of dry ionizing air, or ionic contamination on a surface can greatly increase the distance at which break over will occur. Once the arc is established, it ionizes an electrical path which is much lower in resistance that the initial break over voltage required to jump across the electrodes and the two points of potential can be moved much farther apart and they will still conduct... What are you trying to do? Bill Brooks -----Original Message----- From: John Smith [mailto:[log in to unmask]] Sent: Wednesday, May 04, 2005 2:09 PM To: [log in to unmask] Subject: Web site question Is there a guideline that references how far a static charge will jump? i.e. a 500v charge could be expected to jump or ark how far? ******************************************************************* This email and any files transmitted with it are confidential and intended solely for the use of the individual or entity to whom they are addressed. If you have received this email in error please notify the system manager. 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