[Amps] Arc distance

Tom W8JI w8ji at w8ji.com
Fri Jul 28 07:53:22 EDT 2006


I wouldn't want people to walk away with the false idea that 
spacing is the only major parameter that determines arc 
distance in a given dielectric media. The shape is extremely 
important, as are any small sharp edges.

A blunt smooth surface for a given spacing can have several 
times the voltage breakdown of a similar spacing with a 
sharp edge or even a very small sharp protrusion.

People who think they can look at a complex structure and 
predict where it will break down based on spacing are 
kidding themselves and fooling anyone else who believes 
them.

I suspect the incorrect bandswitch and capacitor breakdown 
voltages that are tossed out as "fact" come from looking at 
gaps or perhaps testing parts that are exceptionally smooth 
or testing under other best-case conditions, or maybe even 
just invented without any factual basis at all.

73, Tom W8JI 




More information about the Amps mailing list