Just side comments to hopefully get discussion going... (See Gabi's email below)
1. Can anyone else verify the breakdown voltage of 1Megavolt/meter for air? Seems different than what I can remember; but I don't have a reference handy. It also seems to me that this would be very dependent upon humidity and pollution degree? 2. I'm assuming that 10mil means .010". I would think that such a small gap would be considered a potential problem in certain circuits. If this design were used in a hazardous circuit, wouldn't a safety test lab short out the gap just to see if a hazard develops? 3. I've seen this done before on circuitboards. The ones that I've seen actually had a thin neck of a trace connecting the points of the triangles. I always thought that this was done as sort of a cheap fuse. Is this true? My apologies to Gabi for not being able to answer his original question; but hopefully addressing my additional questions will get a more complete answer in the long run. Chris Maxwell | Design Engineer - Optical Division email [email protected] | dir +1 315 266 5128 | fax +1 315 797 8024 NetTest | 6 Rhoads Drive, Utica, NY 13502 | USA web www.nettest.com | tel +1 315 797 4449 | ************ Gabi's Original Email *********************************** > 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: [email protected] with the single line: unsubscribe emc-pstc For help, send mail to the list administrators: Ron Pickard: [email protected] Dave Heald: [email protected] For policy questions, send mail to: Richard Nute: [email protected] Jim Bacher: [email protected] 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"
