Micro SSTC Driver 1V-100V(?) Interrupted/CW

Показать описание

This is a really basic drive based on Steve Ward's Micro SSTC design. I always liked this driver design because it didn't seem picky for me when it came to driving various coils in CW up to a little over 1mhz. Some would have better output than others. The first mod of that driver I built was based around a pure DC battery supply and got antenna feedback through a 74HC14 which would easily allow for feedback via a transformer. It used a fake UCC driver with no enable and I decided to leave it as-is without trying to add the interrupting feature. Another one I tried used a GDT for isolation and I ran it up to about 230v. This one adds Ward's startup feature using the 555 timer as a background oscillator which is set to pretty close to the resonant frequency of the secondary (though it could be set to nearly anything of lower frequency it seems.)
This allows for reliable feedback via a transformer (mine is 32 turns) or antenna and also interrupted operation. Like with the more basic driver you have to play around a little bit with the values of the coils to get the most output but I haven't seen anything like what I can get from the push-pull circuits. I'm going to work on more of those after getting this out of the way.

I can sort of manage the current draw and power in the arcs by varying how I load the primary capacitors at the time, which in this video is just a tiny bit via bleeder resistors. If I were to say load them with a 120v bulb instead, the arcs become hotter and the current draw goes up, and the brightness of the bulb would vary depending on how I loaded the secondary. Storing charge in the capacitors this way can bring the voltage to over 400v instantly and shock the crap out of you without bleeding them.

I haven't tested this at over 50V but I'm assuming it will take about 100V so long as it's interrupted. CW probably not without a different switch and better cooling. The 555 background oscillator can just be set to a max of around 1mhz and adjusted down with a Pot for use with various coils. I prefer to just add small jacks on these circuits now and plug in my own external interrupter to avoid needing to add extra on board oscillators and amplifiers for audio or midi every time I build one.

Class-E operation is possible but you'd have to pick a set of coils and stick with them for that, which I might do eventually. I already have smaller push-pull setups that run 12-24v or so and give much longer arcs so this driver is just for simplicity of interrupting.