>
> Here's an interesting challenge.
>
> How can you charge a 450V 160uf Electolytic capacitor
> from a 12V 1A source, quickly as possible to a
> pre-defind charge upto 300V.
>
> Once charged I want to disconnect the charge circuit
> and connect another circuit that will quickly
> discharge the capacitor.
>
> A bit like manually connecting the capcitor to a
> charge circuit that is connected to a DC meter, when
> it reaches 300V manually connecting it to a discharge
> circuit.
>
> Charge circuit connected via a relays so once charged
> I can fully disconnect it from the charger.
>
> Also just to make it a bit more complex, I want to
> test that the capacitor has reached it's charge and
> get the result into a micro controller.
>
> Think of an automated machine that tests low power
> high voltage ignition coils .
>
> Known variables
>
> Charge must reach 300V or higher
>
> Once 300V is present on the capacitor it must be
> verified and then injected into the discharge without
> any effects from the charge circuit being possibe.
>
> While the capacitor is being charged it must not be
> connected to the disscharge circuit.
>
> Supply cannot be over 12V 1A
>
> Charge speed is important.
>
> Andy Faulkner

>
> Andy, its not hard to do. I've pulled apart a low
> cost "personal protection" device, the ones that
> zap the attacker with a high voltage.
>
> It was very simple, 2x C cell batteries for high A
> low V supply. A simple one-transistor inverter
> (self excited) and simple low-turns transformer
> with a single rect diode. That charged a 2kv polyprop
> cap to a few hundred volts, and very quickly,
> about 1/20th of a second.
>
> Then there was a simple sparkgap, so when the cap
> volts got high enough it jumped the gap and this
> energy dump was fed straight into a low turns
> primary of a simple autotransformer. The secondary
> of the autotransformer was about 120kV, at about
> 20 "zaps" per second. This is similar to a tesla
> setup.
>
> Interesting that the crude mass-produced thing
> just keep charging the first cap, the inverter
> was not disconnected at all for the secondary
> discharge/sparking.
>
> One transistor, one diode, and a couple of discretes.
> And no PIC chips in sight!
> -Roman
>
> Andy Faulkner wrote:
> >
> > Here's an interesting challenge.
> >
> > How can you charge a 450V 160uf Electolytic capacitor
> > from a 12V 1A source, quickly as possible to a
> > pre-defind charge upto 300V.
> >
> > Once charged I want to disconnect the charge circuit
> > and connect another circuit that will quickly
> > discharge the capacitor.
> >
> > A bit like manually connecting the capcitor to a
> > charge circuit that is connected to a DC meter, when
> > it reaches 300V manually connecting it to a discharge
> > circuit.
> >
> > Charge circuit connected via a relays so once charged
> > I can fully disconnect it from the charger.
> >
> > Also just to make it a bit more complex, I want to
> > test that the capacitor has reached it's charge and
> > get the result into a micro controller.
> >
> > Think of an automated machine that tests low power
> > high voltage ignition coils .
> >
> > Known variables
> >
> > Charge must reach 300V or higher
> >
> > Once 300V is present on the capacitor it must be
> > verified and then injected into the discharge without
> > any effects from the charge circuit being possibe.
> >
> > While the capacitor is being charged it must not be
> > connected to the disscharge circuit.
> >
> > Supply cannot be over 12V 1A
> >
> > Charge speed is important.
> >
> > Andy Faulkner
>
> --
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