Re: Solid-state coil (gate xfrmr question)

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <cwillis-at-guilford.edu>


Hi Eddie, Ed, Malcolm,

Thanks for your most informative responses.  I just sent out another post
to the list with the same questions because I thought my e-mail was down
and not because your answers did not suffice.  I also put photos and some
more description of the current state of this SSTC setup on the web at
www.angelfire-dot-com/electronic/cwillis/sstc.html.  I have some photos of the
oscillosope while the coil was running as well, so you can comment on how
good / bad the setup is doing from an FET survival standpoint.  The biggest
question still outstanding to me is why I get such a high drain voltage
(about twice the DC supply voltage) on the pulses.

Eddie's suggestion that my ferrites were too small, wrong type and wound
with too few turns sounds exactly like the case.  Although I don't know
what types of ferrite these all were, at least one was a ~0.6" OD,  0.1 -
10 MHz tiny little thing and I only had ten turns on it.  I'll follow your
advice and sack a few old switching supplies for their toroids.  Malcolm
corroborated what you said also.

In regards to Malcolm's question about power supply, I am using rectified
and filtered AC line power (and, until I'm really sure of myself, a
variac.)  And finally, Ed, the setup is a conventional tesla coil and not
an ignition coil.  I admire the GMHEICSLR (?) efforts very much but I just
don't have the nerve to try to get 6"+ out of one of those things! 

Thanks, y'all!

Carl