Re: gdt

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

Original poster: "Malcolm Watts" <m.j.watts-at-massey.ac.nz> 

On 11 Jul 2004, at 17:26, Tesla list wrote:

 > Original poster: Matthew Smith <matt-at-kbc-dot-net.au>
 >
 > Claude Masetto wrote:
 > >Could someone tell me the best way to wind a GDT with a turns ratio
 > >of 1:2:2 and still maintain good coupling between primary and
 > >secondary. Also, what seems to be a good number of turns.
 >
 > I'd suggest a trifiliar winding on a ferrite toroid.  Possibly one of
 > those filter toroids out of a PC power supply?  Anyone know if that
 > material is suitable?
 >
 > Cheers
 >
 > M

Iron powder cores are definitely out. The permeability is low and the
high AC current levels will heat them like crazy. The best
recoverable cores are either the actual transformer cores *as long as
they aren't gapped* or the toroidal ferrite cores one typically sees
threaded over some of the leads inside CRT monitors.
      Best results for the winding should be obtained if the windings
are not only n-filar, but also twisted together as it is more
important to get high coupling between windings than it is to get
high coupling between windings and the core.

Malcolm