Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx> Hi Greg,The bar graph scope has a frequency response of 1MHz or a bit higher. But the actual power arc to ground is only about 20nS in length. tto fast for the scope normally, but makes a nice clear picture ;-)) So you are just seeing the voltage on the top terminal rise and the current it takes to reheat the arc channel. After the arc, the current often continues to flow as the secondary inductor's energy is also grounded. Later on, the primary energy may recharge the secondary to possible even causing another power arc into the hot channel.
The actual power arc event was caught here: http://drsstc.com/~streakcam/pictures/32/PA090027b.JPGIn the upper arc, the power arc event "blipped" the scope as a quick positive pulse. A fainter similar pulse is here:
http://drsstc.com/~streakcam/pictures/32/PA090034b.JPG and here at the bottom: http://drsstc.com/~streakcam/pictures/32/PA090063b.JPGSo the scope is too slow to normally see the actual power arc event. But it sometimes catches it due to noise or something.
I need to "update" this too :-))
http://drsstc.com/~scantesla/Strike.pdf
Cheers,
terry
At 08:23 AM 10/12/2006, you wrote:
Hi Terry, That's an impressive and clever feat of instrumentation; Congratulations!One feature that seems to be apparent from your pics is that the light output of the arc is highly non-linear vs. current. That is, the arc intensity seems to occur over a relatively short period of the current haversines. Is that true, or am I not reading the time scales correctly?-GLOriginal poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx> Hi,As I look though the pictures... For streamer buildup and strike, these are good ones:http://drsstc.com/~streakcam/pictures/32/PA090046b.JPG (positive) http://drsstc.com/~streakcam/pictures/32/PA090023b.JPG (negative) This shows a lot of "post strike" activity: http://drsstc.com/~streakcam/pictures/32/PA090039b.JPG Some show an odd 2X Fo feature usually before the main strike: http://drsstc.com/~streakcam/pictures/32/PA090024b.JPG Here is a "4X Fo" pre-strike feature: http://drsstc.com/~streakcam/pictures/32/PA090037b.JPG The current shows them up easily....Peter first found these higher than FO features... Maybe a 2nd, 3rd, 4th... harmonic effect or something... I think his higher light sensitivity pictures show them better... I can't keep track of all my pictures, let alone his too ;-))Cheers, Terry Hi All, Very busy day today!! Many questions, but not a lot of answers :o))First the easy stuff... Peter was wondering if my Streak Oscilloscope's bandwidth was "ok" since some of the readings looked different than one would expect... .....