Russell McMahon wrote:
>

> This one transistor concept is pretty bad stuff :-) (if I do say so myself).
> It has all the worst features of my earlier designs and then some.
> If it decided not to oscillate reliably I wouldn't be excessively
> surprised!!! :-)
> As a brainstorming idea it has its place.
> On reflection it would be possible to give it a little "help" - and this
> applies to the other simple circuits as well - with a small overwind coil on
> the primary inductor.


Hi Russell, sorry the one-transistor design is
dead in the water. The zener "knee" is way too soft,
as we only have about 200mV of ripple at C1 to
drive the transistor.

It oscillated PERFECTLY, ALWAYS, but could not
drive the transistor directly into saturation.
The transistor output looked like a sinewave and
had no efficiency.

The only way to get it more effcient requires
increasing the ripple at C1, which kills efficiency
in its own way.

Yes I think a second winding will help to get it
up and running, but that level of complexity really
isn't justified by the final result... The 2-tran
circuit is only one more resistor and one more
transistor, and works pretty good with a wide
range of cheap inductors. :o)
-Roman

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