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Re: Measuring Output Current from a NST
to: Ross
Yes, and it's so easy it will make you sad that you damaged your meter.
For current testing you should almost never us a standard series
multimeter.
Pick up a surplus analog meter 0-100 ma AC or other suitable range and set
it on a big piece of plastic. Now it's insulated and you can run your Hv
through it and measure currents with no problems. Fair Radio Sales and C&H
Sales both carry surplus meters as well as do local hamfests -- expect to
pay approx $1-$5 for such meters.
If you want to use your multimeter then pick up a small current transformer
-- toroid type -- and run the HV through in a piece of neon sign
transformer HV wire or non-resistive automotive spark plug wire.
Any time you break any ground connection using a digital meter --- well,
you discovered the result.
Regards,
Dr.Resonance-at-next-wave-dot-net
----------
> From: Tesla List <tesla-at-pupman-dot-com>
> To: tesla-at-pupman-dot-com
> Subject: Measuring Output Current from a NST
> Date: Wednesday, February 03, 1999 5:07 AM
>
> Original Poster: "Ross W. Overstreet" <ross-o-at-mindspring-dot-com>
>
> The first several times I tried to measure the output current of my NST
> bank everything went great. Last night things took a turn for the worse
> when the fuse blew in my Fluke 77 series multimeter and the arc started
> "looking around" inside the DMM for somewhere to go. I managed to burn
> a hole in the PC board before I realized that the funny buzzing sound
> was comming from the meter. I haven't examined it too carefully yet, but
> it seems to be OK. No components exploded and the trace on the card
> isn't damaged too bad. Guess this is a bad idea, huh? Especially when
> the fuse somehow blows and suddenly the two terminals inside the meter
> become a sealed spark gap, hehehe
>
> Is there a simple (cheap) way to measure the current output of NSTs?
> Anyone had good luck with current shunts made from readily available
> resistors?
>
> Burning stuff up BEFORE the coil is finished, muhahaha
> Ross Overstreet
> Huntington Beach, CA
>