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ALF: why not DRSSTC?



Original poster: Steve Ward <steve.ward@xxxxxxxxx>

Hello all,

This message is particularly aimed at Greg Leyh, but I would like comments from others as well.

As far as i know (and i might be wrong) Greg is currently working on a scale model of his ALF towers. This prototype uses the OLTC topology to drive the Tesla resonator. Since silicon appears to be the weapon of choice already, I'm curious as to why not DRSSTC instead of OLTC? It seems (at least on our hobbyist level) that the DRSSTC can outperform an OLTC for similar amount of silicon used. The DRSSTC also does not have the difficulties that the OLTC intruduces as far as primary coils are concerned (many OLTCs are just 1 or 2 turn primaries). The DRSSTC also does not have to store the entire bang energy in the tank cap (another benefit)

One possible issue i could see is this: 1200V devices will only get you so far until you are looking at using single turn primaries and giant tank capacitors (resembling the OLTC, but this is even more problem for OLTCs as they scale up as well). So you might be forced to look at 1700V or 3300V devices. But I'm aware that these devices also have their limitations (they are slower and have greater losses, but i think these are not much to overcome). Ive heard that the real problem is from cosmic rays causing the devices to turn on or avalanche (what is the exact mechanism?) when you don't want them to. But, wouldn't this also be a problem with using higher voltage silicon in the OLTC?

So for each problem I see with scaling a DRSSTC to ALF size, it seems an OLTC would have the same problems. As I (and others) see it, the DRSSTC is overall a better topology. So to summarize: why OLTC over DRSSTC? I'm guessing Greg has thought about this more than i have, so i would really like to hear his response.

Thanks,

Steve Ward