Re: differential probes

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

Original poster: "Daniel Barrett by way of Terry Fritz <teslalist-at-qwest-dot-net>" <dbarrett1-at-austin.rr-dot-com>

     Hi All!
     Just a thought here- This spark gap section could really just be part of
the PC layout: Route the potentially high current signals with maybe 10 mil
tracks, separated from each other by an inch, but "T" off a spark gap
between these tracks. That way an arc will occur in a controlled spot on the
board and the feeding traces will be small enough to vaporise. Should
provide an easy to make fuse, but I guess the board would need a lot of
rework between accidents ;)
db

----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, July 15, 2003 10:54 PM
Subject: RE: differential probes


 > Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>
 >
 > Hi Jimmy,
 >
 > I have the 'stuff' here to find the "precise 0.177 caliber BB spacing" but
 > ran out of time tonight :-(
 >
 > I am thinking you should not order any boards till we can work some of
 > these details out more.  Today, I talked to some folks that had some
strong
 > arguments for using cap in parallel with the resistors.  I fear that
 > ordering boards now would mean that they would be "obsoleted" pretty
 > quickly...  I don't know how much the boards cost, but I would not want
you
 > spending and serious money on something we know is going to change...
 >
 > So, I think there are too many question to go getting boards right now.
We
 > need to work more on this front end fusing and capacitance stuff.  I think
 > I can get this stuff answered in a few days, so we would have a good
chance
 > that "that" version would be "the" version.
 >
 > Cheers,
 >
 >          Terry
 >
 >
 > At 08:41 PM 7/15/2003 -0700, you wrote:
 > >Hi,
 > >
 > >My stun gun used two staples for a spark gap. They
 > >formed an X shape, and could be adjusted by pushing on
 > >it. I would just need a way to calibrate it. If I used
 > >"BBs" or 0.25 inch balls, I could solder them in
 > >holes, and just look up the breakdown voltage for
 > >spheres.
 > >
 > >I'll cut the boards up wherever it looks like it needs
 > >it.
 > >
 > >
 > >--- Tesla list <tesla-at-pupman-dot-com> wrote:
 > > > Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>
 > > >
 > > > Hi Malcolm,
 > > >
 > > >
 > > > >I haven't downloaded the file as I don't have a
 > > > suitable program to
 > > > >open it with available on the NW. I do have a tip
 > > > to deal with the
 > > > >problem mentioned in the previous paragraph: the
 > > > way to increase the
 > > > >isolation barrier without consuming a lot of board
 > > > space is to
 > > > >physically cut a slot in the board across the
 > > > isolation barrier. This
 > > > >gets rid of the problem of surface tracking. I
 > > > presume fibreglass is
 > > > >the material of choice for this board? <paxolin or
 > > > anything like it
 > > > >is OUT>.
 > > > >
 > > > >Malcolm
 > > > ><snip>
 > > >
 > > >
 > > > That is a very good idea!  Tracking under these long
 > > > resistors could be a
 > > > big problem especially with a little left over flux.
 > > >
 > > > Jimmy - Could we drill 4 big holes under the
 > > > resistors?
 > > >
 > > > Also, I think hooking to the board with very thin
 > > > wire and then having
 > > > spark gaps on the board to take "bad" events is the
 > > > way to go.  Maybe
 > > > solder "BB's" or 1/4 inch balls to the board at some
 > > > spacing.  The spark
 > > > gaps could take a big high voltage high current hit
 > > > (arc at 2500V) and then
 > > > the thin wires could blow apart and basically take
 > > > things out of the
 > > > circuit.  I'll see if I can figure something simple
 > > > out there...
 > > >
 > > > Cheers,
 > > >
 > > >          Terry
 > > >
 > > >
 > > >
 > >
 > >
 > >=====
 > >Jimmy
 > >