On 02/08/2013 10:29 PM, Steve Ward wrote:
This brings up something interesting that i noticed with my special
Quasi Constant Wave (QCW) SSTCs. I can control the rate of growth for
the spark, and also the rate of decay. Slowing down the growth time
does make the spark sound kinda "fluffy", but giving it a sharp turn
off (removing the power from the spark fast, like 20uS) makes it quite
a bit louder. I think the answer is simply that it cools down a lot
faster, so you still get a significant dp/dt (change in pressure) due
to cooling more rapidly. I cant imagine there being any sort of
vacuum being generated. But yes, the cooling part of the cycle makes
noise too ;-). The sparks are still not nearly as loud as a
conventional tesla coil making similarly sized sparks, so im guessing
its the heating part of the cycle that makes most of the sound.
Could it be that the gap itself is a major contributor to the noise
generated by a conventional coil?