Gabi, In my experience these crude spark gaps do work - for a while. The tips of the triangles tend to erode during surge testing, thereby raising the voltage required to jump the gap. I like the fact that you are only thinking of them as an addition rather than as primary protection. There are several drawbacks to be noted.
1) As already mentioned, the pads are fragile and erode with actual usage. 2) The discharge voltage is somewhat unpredictable and varies with dust, humidity, etc. 3) An audible "snap" is heard whenever a spark jumps across the gap. This may be unnerving to a customer who hears this. It may be perceived as a component failure. If cost allows I would recommend using a gas-filled discharge device instead. These are very predictable and repeatable, degrade much more slowly, and are much quieter. Scott Lacey -----Original Message----- From: owner-emc-p...@majordomo.ieee.org [mailto:owner-emc-p...@majordomo.ieee.org]On Behalf Of Gabi Hoffknecht Sent: Wednesday, February 20, 2002 11:33 AM To: emc-p...@majordomo.ieee.org Subject: Using PCB traces as transient voltage suppressor Hi all, I have seen PCB designs with two triangular shaped copper pads pointed towards each other at very close proximity, meant as an air gap discharge path for transients. Does anyone have information about such designs, whether they work and how well ? At a breakdown voltage for air of 1 Megavolt per meter, they should theoretically work: 10mil distance would have a breakdown voltage of only 254V. Such a PCB design basically comes for free, so I was thinking of adding it on top of my already existing series impedance - TVS network. Thanks in advance for your comments. Best regards, Gabi Hoffknecht ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list" ------------------------------------------- This message is from the IEEE EMC Society Product Safety Technical Committee emc-pstc discussion list. Visit our web site at: http://www.ewh.ieee.org/soc/emcs/pstc/ To cancel your subscription, send mail to: majord...@ieee.org with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: emc-p...@hypercom.com Dave Heald: davehe...@mediaone.net For policy questions, send mail to: Richard Nute: ri...@ieee.org Jim Bacher: j.bac...@ieee.org All emc-pstc postings are archived and searchable on the web at: http://ieeepstc.mindcruiser.com/ Click on "browse" and then "emc-pstc mailing list"
