Re: PC board primaries

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "R Heidlebaugh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rheidlebaugh-at-zialink-dot-com>

on 12/11/01 7:57 PM, Tesla list at tesla-at-pupman-dot-com wrote:

> Original poster: "Jim Lux by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <jimlux-at-earthlink-dot-net>
> 
> Indeed... creeping sparks can typically jump 3 times the distance in free
> air. On a PC board the problem is aggravated by the "knife edge" of the pc
> board trace.
> 
> ----- Original Message -----
> From: "Tesla list" <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Tuesday, December 11, 2001 11:34 AM
> Subject: Re: PC board primaries
> 
> 
>> Original poster: "Peter Lawrence by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <Peter.Lawrence-at-Sun-dot-com>
>> 
>> 
>> The thing I wonder about regarding all these PC-board primary posts is
> that
>> the epoxy-glass board may act as a spark conductor, in the sense that in
>> many situations a spark may only be able to jump say 1 inch in air will be
>> able to jump more than 1 inch if there is a non-conductive surface (air to
>> non-conductor surface) between the electrodes, for example the circuit
> board.
>> This comes up in capacitor design, the "air" distance between conductors
> in a
>> capacitor needs to be much longer than 1-inch-per-75kV since sparks tend
> to
>> travel longer when there is a "surface" to travel along. I'm not sure what
>> the correct terminology for this is, but I'm sure many folks on this list
>> know about and have also experienced what I'm talking about...
>> 
>> Pete Lawrence.
>> 
>> 
>> 
> 
> 
> 
Surface conduction on any un clean material is a problem where salt water
vapor may be found , But I have had no problem on fiber-glass board. I have
used PC board capacitors for years with no problems.
   Robert  H