Re: term understanding: voltage reversal.

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

Original poster: Jim Lux <jimlux-at-earthlink-dot-net> 

At 08:02 AM 2/19/2004 -0700, you wrote:
>Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com>
>
>
>Bert has a great point here.  A nice neat equation.  If you use a storage
>scope to see the primary discharge waveform you can find the nearly exact Q
>factor of your primary circuit.  Knowing the % voltage reversal you can
>solve the equation for effective Q factor.
>
>Another method is to observe the decrement (decay) factor which is related
>to circuit resistance.  You can use this information to determine effective
>dynamic Q factor was well.
>
>You fire the primary with and without the sec in place --- in a single shot
>mode.  Do not try this at high rep rates or the excessive Q without the sec
>will blow the cap.
>
>In a single shot mode you can compare the loaded and unloaded Q factor and
>thus determine the effective impedance of the primary looking into the
>secondary load. This information can also be used to determine the peak
>current in the primary and then compared to actual measurements with close
>agreement.


Based on the fact that the usual TC isn't a nice RLC, the relationship 
between Q and VR isn't all that great anyway.  The standard formula assumes 
an exponential decay, which would be the case if the losses were 
resistive.  However, a big loss is the spark gap, which is hardly a nice 
resistor.  I seem to recall someone coming up with some measurements that 
showed a linear decay is more realistic.

In any case, the VR is quite large on TC duty..