Flyback coil driver progress, not perfection

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

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

I finally got an indefinitely sustainable flyback coil discharge.  Its
only about 10kV, but the circuit is way overengineered to protect the
transistor.  I am using an NTE52 ($6.00) with an ultrafast recovery
diode from base to emmitter, so that b-e breakdown is impossible on
negative base swings.  I am also using a damper diode- Same ultrafast
recovery diode in series with the collector.  The collector then has a
1600V 0.01uF cap from collector to emitter.  No more HV spikes.  Circuit
draws 0.5A at 30V, and nothing gets hot.  The transistor doesn't even
get warm.  I think all power is dissipated in the flyback parasitics.

Now I can work back to something that puts out 30 or 40kV.  I still have
no clue why my older much simpler circuit doesn't work any more.  If I
get it working again so that the coil puts out a nice fan shaped
discharge, I will post the circuit. Rob.


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The Numeric Python EM Project

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