Re: Driving circuit FET problem

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

Original poster: "by way of Terry Fritz <twftesla-at-qwest-dot-net>" <dhmccauley-at-spacecatlighting-dot-com>

 > Hi George,
 >     When dealing with transformers of any kind, it is
 > important to remember one simple equation: power in = power
 > out. It takes a certian amount of voltage and current to
 > drive the primary side of a tranny. The voltages and
 > currents on the secondary are inversly proportional to that
 > of the primary (depending on whether it's a setp up or step
 > down) and power in must equal power out. When you short the
 > secondary, the voltage drops to zero and the currnet goes
 > way up. The primary is probably trying to compensate and is
 > pulling too much current from the drive circuitry, shutting
 > it down...

Well not true.  Power in almost never equals power out.  And these losses
aren't small enough
to just neglect either especially when dealing with larger and larger
transformers.

At high frequencies, you can experience quite a bit of losses to the core.
My 200kHz high voltage transformer requires
cooling for proper operation.  I could only wish power in = power out ! ! !

If you want some more information on SSTC's, check out my website:

http://www.spacecatlighting-dot-com/teslacoil.htm

I've already built two solid state tesla coils and am working on a Solid
State magnifier type coil this winter.  I'm also putting together a page
which will have lots of theory and simulation data, examples for solid state
tesla coils.

Dan







 > Just a thought.. Anyone else have any thoughts? I'm not too
 > up to date with SSTC driver circuitry..
 >
 > Coiling In Pittsburgh
 > Ben McMillen
 >
 > --- Tesla list <tesla-at-pupman-dot-com> wrote:
 >  > Original poster: "george hadle by way of Terry Fritz
 >  > <twftesla-at-qwest-dot-net>" <ckreol1-at-yahoo-dot-com>
 >  >
 >  > hi, My driver circuit its an ignition coil driven by a
 >  > FET protected by schottky diodes.
 >  > The problem has several symptoms, all independent of
 >  > the TC being connected or not.
 >  > If I short the hv terminal to ground, the circuit
 >  > completely ceases output.  It can spark between these
 >  > two terminals without problem, its only when directly
 >  > shorted it messes up. Whether the output is latched ON
 >  > or cut OFF, I think its latched ON.
 >  > I'm running it at audio freq. and the sound of the
 >  > coil completely stops.
 >  >
 >  > I can rectify the problem for a few seconds one of two
 >  > ways.  Turning off and back on.  Or changing the
 >  > frequency of the FET driver, which is a schmitt
 >  > trigger oscillator.
 >  > any ideas?
 >  > thank you very much
 >  > george
 >  >
 >  > _
 >  >
 >
 >
 >
 >
 >