Re: : Simulation

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

Original poster: "Luc by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ludev-at-videotron.ca>

Hi Charles

Tx Charles for the interest you give to my question Richie find
the solution I response to him privately but some other seem to
be interested I copy the message send to him:

"Hi Richie 

Tx, if I increased the "time domain points per cycle" from 100 to
5000, the "bode analysis points per cycle" from 50 to 100 and the
tolerance from 1% to .01% the artifact disappear.

So much to learn and so little time."


Cheers,

Luc Benard 

Tesla list wrote:
> 
> Original poster: "R.E.Burnett by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<R.E.Burnett-at-newcastle.ac.uk>
> 
> Hi Luc,
> 
> I wonder if the time steps for the simulation are too large,  and you are
> seeing some aliasing effects.  There should be no notches in this trace.
> 
> The notches may just be an artifact of the display.  Does the ringdown
> still diplay notches if you "zoom-in" with the scope ???
> 
> Failing that I would look to either decrease the time-step or increase the
> number of sample points if that is possible with Electronic Workbench.
> Microsim is good if you still have problems ;-))
> 
>                                                         -Richie,

snip

> > Hi guy
> >
> > I start to play with an electronic simulation software, I make a
> > crude simulation of a primary circuit I put a couple of
> > resistance on the circuit to be more realistic. One thing is
> > strange normally the notch are explained by the exchange of
> > energy from the primary to secondary and back. On my circuit I
> > have notch but no secondary only a primary inductance could
> > someone explain why I have notches, is it an artifact an harmonic
> > or something else ?
> >
> > I put a gif of the screen capture at:
> >
> > http://pages.infinit-dot-net/luc2/simulation.gif
> >
> > Tx for your time,
> >
> > Luc Benard
> >
> 
> A real puzzlement Luc. I played with similar set-ups but at much lower
> voltages (12V rather than 3kV dc) and got the expected damped rf signal.
> When I put a tuned circuit near the coul then nulls would appear like those
> shown in your very nice gif.
> 
> Anyway I did the usual calculations on your circuit and got the resonant
> freq. of 251kHz which appears to match yours on the scope if the time base
> was magnified by 5. Noticing about 10 RF cycles between nulls that would
> very roughly match a double tuned transformer with a coefficient of coupling
> of around 0.3 or 0.4.   The  thing I noticed about your circuit was the 200
> ohm pot. in series during the ringing. XL of the 20uH coil works out to
> about 31 ohms, so to get ringing anyway near what you got this pot would
> have to be set very low, maybe about 3 ohms or less. I suspect it is a wire
> wound pot  adding some unusual reactance to the circuit. However, it's still
> a mystery to me. I certainly wouldn't let loose of this situation until the
> mystery was solved
> 
> Good luck
> 
> Chuck