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High Voltage Test Equipment




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From:  Jim Lux [SMTP:jimlux-at-earthlink-dot-net]
Sent:  Friday, March 06, 1998 12:54 AM
To:  Tesla List
Subject:  Re: High Voltage Test Equipment


> 
> 
> ----------
> From:  Homer Lea [SMTP:HomerLea-at-aol-dot-com]
> Sent:  Thursday, March 05, 1998 2:05 AM
> To:  tesla-at-pupman-dot-com
> Subject:  Re: High Voltage Test Equipment
> 
> In a message dated 98-03-05 00:46:30 EST, you write:
> 

> I just sent off new specs:
> -------------
> post script: I ended up getting 400 15meg resistors. They are small (1/8)
> watt. My plan is to string them in series, put them in a Tygon tube and
fill
> with oil. I will coil up the tube so it isn't 20 feet long. I assume the
> inductive reactance will be zilch compared to the 6 billion ohms of
resistors
> The resistors will be in series with a  50 or 100 ua meter connected
through a
> full wave rectifier bridge. Does anyone know how much voltage I can put
across
> each resistor?? I am hoping for at least 500 v each and dreaming of 1000
v.

The power dissipation at 1000V would be pretty high for the application
(1e6/15E6 = 1/15 or roughly half the rated power). Oil immersion will help
of course, assuming that the oil can flow around the resistors. 1/8 watt
resistors are usually rated at 200-300 Volts. I wouldn't bother with the
tygon tube, just immerse the whole assembly in oil in a PVC pipe or
something.

50 uA through 15 Meg is 750 Volts, btw....
> ------------------
> A 20 foot tube it not small, even coiled up. Is that going to screw me
up? My
> original thought was simply to measure the output voltage of coils rather
than
> wave forms.
> jim heagy

Output voltage of a tesla coil, I presume? The parasitic C (many pF) will
bite you big time at 100 kHz frequencies. For AC a capacitive divider might
be a better idea.