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Re: NE555 driven coil WAS:Re: SCR driver coil...
Hi Paolo,
> Original Poster: Paolo <pagaiard-at-geocities-dot-com>
> Hi all,
> I have to realize (for an electronics exam) a solid state driven TC
> with a very high efficiency.
> I need to know your opinion on a couple of ideas.
> Suppose I build a ne555 based impulse generator which
> makes 1 us long pulses with a (say) 100-500Khz repetition rate.
> Then I send those pulses into a power transistor (a BJT working a
> current controlled switch, of course)
> via a 2N2222 based current buffer (say a follower emitter).
>
> I could drive directly an inductor tightly coupled to a tesla
> secondary
> winding but with the power available (30W or so) I suppose the yeld
> would be quite low.
>
> But what if I feed a LC circuit with those current pulses?
> The LC must be tuned and coupled to the secondary winding, and feeding
> it with 1 us pulses, maybe with a repetition rate tuned to the TC
> frequency
> should create into the LC couple powerful oscillations
> and thus make for a high power yeld into the secondary winding.
>
> I would like to read your opinion on this subject, which is of the
> maximum importance for me,
> Thank you in advance,
> Paolo Gaiardelli
If you can time and phase your pulses accurately you will build
oscillations up in the secondary to a level allowed by the power and
shunt impedance. The moment a discharge arises or something changes
tune, the oscillations will die to a low level again. I did this in a
coil for experimental purposes a few years ago.
A couple of years ago I scored 6" p-p sparks in a mini-twin
disruptive coil running a 30W input power. I'd recommend this mode of
operation any day.
Malcolm