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Re: leader strike photo idea

Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi Jim,

I tried that here but with a generic photo from Dan.

http://drsstc.com/~piranha/PIRANHA/Corrected-PetersPictureWComents.jpg
The problem is, with the coil running at like 300BPS, to catch just the right strike to capture on the scope. If the camera had a flash "hotshoe" it would be much easier to sync the scope. Having the scope in the picture too would be cool but the screen persistence would just make a blur. Digital scopes are no hope. Even though they can clearly pick out a single hit, they have a significant digital delay time before the computer decides to upload the event to the screen. To get the scope in the picture too, one would have to play with mirrors to get it the same distance away but in a safe place to retain the focus.
Steve Conner suggested using an LM3914 or two as a bar graph LED driver that could just be placed to show up in the picture too. It would work just like a scope then. But we are not sure if the LM3914 can operate fast enough (at "least" 100kHz).? If anyone has tried to run the LM3914 at say 100kHz and above I would like to hear from you!
Peter and I have been playing with polarity indictors too like I mentioned in the other thread. 

http://drsstc.com/~streakcam/instruments/Indicator-00.gif

http://4hv.org/e107_files/public/1158886233_10_FT15766_hvrotmirrorpolarityledresistors.jpg

http://4hv.org/e107_files/public/1158939531_10_FT15766_hvrotmirrorpolaritydetailnegstrikelong.jpg
Mine could be directly calibrated if the LM3914 thing would work. I don't have any here to play with. It also needs high brightness LEDs. 

Cheers,

        Terry



At 09:25 AM 9/23/2006, you wrote:

Here's something that might be interesting to try, analysis wise..
If you have your scope hooked up, and it captures the waveform of, say, the E field, or the base current, you could turn that into an image and scale it so that it's the right number of pixels/microsecond and lay it along side the streamer image. (running from bottom to top, for instance).