Take care, Bart Scott Bogard wrote:
perhaps this is a very inaccurate approach, but, spark gaps all emit a certain pitch sound. This is especially noticeable on rotary gaps. You could use a tone generator to match the pitch of your spark gap, and calculate the BPS through the frequency of the sound. As I said that will only give a rough estimate of the breaks per second (400ish...). You would probably be better off to put a photo sensor close to the spark gap, put it through a filter, and measure the flashes per second with an oscilloscope, as Bart already suggested. Just musing.Scott Bogard. bartb wrote:Hi Gary,Actually that was my first thought on this. Simply trigger a pulse and record it. But then I thought "well it's just as easy to record the whole thing". I may end up doing that in the end. I could also measure the voltage drop across the gap itself for each bang, but that does take a bit more work and thought.Thanks for your input. Bart Lau, Gary wrote:I would attempt some sort of low-pass filter at the receiving end - so that each bang results in a single blip and any stray HF stuff is attenuated. But I think I tried as much, unsuccessfully, as had I been successful, I could have just fed the result into a counter with a suitably long time base for a good average PPS count. Good luck!Regards, Gary Lau MA, USA-----Original Message----- From: tesla-bounces@xxxxxxxxxx [mailto:tesla-bounces@xxxxxxxxxx] On Behalf Of bartb Sent: Monday, February 25, 2008 9:46 PM To: Tesla Coil Mailing List Subject: Re: [TCML] Spark gap Hi All,With this thread, measuring static gap bps came up. I will attempt this.I can record hours of run time if needed, but of course I'll record say a 10 minute run. This should give plenty of data for bps acquisition. I'll use a device specifically for data acquisition. This device plugs into my pc via shielded USB and can accept up to 60Vp-p signals.Although I do have the high speed unit capable of 14,400 samples/s, I'll set the sample rate only to what is needed for a decent view. The devicehowever doesn't need to be near the coil (USB's are very prone to noise which causes device hardware connections to be lost). So, I'm thinking of using optics for isolation. Here is my very simple strategy:* Hook up fiber cable near first gap to capture the light created by thespark (where it will always issue). * Convert light to DCV at opposite end. * Record voltage output over 10 minute run.Although I may go further with this, I'm just looking at getting the bpsdata with the gap as is to start. This is only to measure bps and nothing more.I've used this device for acceleration impact testing up to 1050 LB loaddropped at various heights and even for a 2 week non-stopped testing of cycle times on actuation devices. But, I thought it wise to run by the TCML and see if anyone has tried anything like this with a static gap or similar and has any advice I should consider before I start. I'm not sure how the light source will stop and start at the gap. Take care, Bart _______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla_________________________________________________________________ Need to know the score, the latest news, or you need your Hotmail®-get your "fix". http://www.msnmobilefix.com/Default.aspx_______________________________________________ Tesla mailing list Tesla@xxxxxxxxxxxxxx http://www.pupman.com/mailman/listinfo/tesla
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