Spark Gap VI Scope Capture

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Terry Fritz" <teslalist-at-qwest-dot-net>

Hi again All,

I just added the resistance graphs of the gap here too:

http://hot-streamer-dot-com/temp/2003-05-19-10.jpg

http://hot-streamer-dot-com/temp/2003-05-19-11.jpg

Cheers,

	Terry

----------------------------------------------



Hi All,

I figured out this way to look at the voltage across and the current 
through a spark gap:

http://hot-streamer-dot-com/temp/2003-05-19-01.jpg

It is just a tank circuit charged with a high voltage DC power supply.  One 
side of the gap is grounded through an RF ground.  A 100:1 Pearson 101 
current monitor and a TEK6015 probe send the voltage and current to a 
scope.  The power supply and scope probes and circuits are separately 
grounded and well isolated so it is pretty safe for the scope.  It looks 
like this:

http://hot-streamer-dot-com/temp/2003-05-19-02.jpg

http://hot-streamer-dot-com/temp/2003-05-19-03.jpg

The capacitor is really 24nF and the coil is 55uH for a resonant frequency 
of 138.5kHz.  The firing voltage was set at around 3000 VDC.

The scope waveform looks like this:

http://hot-streamer-dot-com/temp/2003-05-19-04.jpg

If you pull it into Excel it is clearer:

http://hot-streamer-dot-com/temp/2003-05-19-05.jpg

One can add an instant power calculation:

http://hot-streamer-dot-com/temp/2003-05-19-06.jpg

Oddly, at times the gap seems to be absorbing power!?

Just the current looks like this:

http://hot-streamer-dot-com/temp/2003-05-19-07.jpg

Note the little pre-burst in the beginning.  These are very common.

The Excel file is here:

http://hot-streamer-dot-com/temp/2003-05-19-08.xls

The raw data file from the scope is here.

http://hot-streamer-dot-com/temp/2003-05-19-09.CSV

The current waveform had a little offset to it, so I adjusted for that in 
the above.

This is just one spark, but it is pretty typical.

Cheers,

	Terry