Re: Scopes Away!
Malcolm Watts wrote:
> The setup consisted of a two coil system with the spark gap
> replaced by 4 paralleled MOSFETS (MTP3055E). The secondary coil with
> Primary Q without the MOSFETs measured around 24.
> With the FETs driven with a gate drive of 8V from a pulse
> generator terminated with a 50 Ohm resistor at the gate/source
> connection. Primary Q measured 9 ( from waveform decrement).
> This is rather close to what you would get with a standard spark gap
Did you notice if the parasitic body diode of the MOSFETs had any
effect on the quenching action? It seems like once the energy was
transferred to the secondary that the FETs could only hold off the
back EMF in one direction, as the body diode would conduct in the
other, resulting in all the haversines of one polarity re-charging
the primary cap back to some DC value.