Re: MOSFET Coil- Ready..Set...

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

Original poster: "Justin Hays by way of Terry Fritz <teslalist-at-qwest-dot-net>" <pyrotrons2000-at-yahoo-dot-com>

Hi Sue and All,

At first, I sampled my MAX913's and MAX4420's. It's a
no-questions-asked service from www.maxim-ic-dot-com, and is really
efficient at getting you to buy from them in the long run ; )

You should only need one MAX913 to get the circuit up and running,
provided you include the diodes on the front-end. I have had one inch
streamers coming off the antenna when the SSTC runs ; ) I have never
killed the MAX913 when these diodes are present. The diodes are
simple germanium RF switching diodes - just about any germanium RF
diode will work here (ex. 1N60) but do not use silicon (ex. 1N4148 or
1N914) diodes, or a zener.

Beware of using a different part than MAX913. I chose it because this
part is highly stable in its linear region, unlike many other
comparators. You can use a different part here provided that:

1). It has an input impedance equal to or greater than the MAX913
2). It is specifically stated in the datasheet that the part is
stable and free of oscillation when used with slow input waveforms.
3). It is a single-supply comparator that will work with supply
voltage=5V.

As several have correctly stated, any schmitt-trigger inverter will
work in place of the 74HC14. If you can find a direct replacement for
any part #'s on the schematic, I urge you to do so. Like MAX4420 =
TC4420, you can use them both. TC4420 is a better chip in my opinion
and it is cheaper; but if you are going to sample and/or purchase
from Maxim anyway, you might-as-well get the Maxim equivalent part
too. Both types work incredibly well.

Indeed, our design is self adjusting and self-tuning. I've also found
it to be very well behaved. The schematic is up to date, and will
work if hooked up correctly. This is one of the few SSTC designs that
can work on a breadboard or perfboard ; )

Sue, if you experience problems with the circuit or need more info,
feel free to email me personally.

Take care,

Justin Hays
KC5PNP
Email: justin-at-hvguy-dot-com
Website: www.hvguy-dot-com