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Re: Homemade Voltage Divider



Original poster: Vardan <vardan01@xxxxxxxxxxxxxxxxxxxxxxx>

Hi,

The Beckman probe will work fine... I worry that the homemade thing might have a defect somewhere... Trust the Beckman first!! Don't "really" hold it (or ANYTHING(!!)) in your hand :-)))

When it fires, there will be very high frequency things that might "shoot through" the Beckman and such.... Use a $10 DVM from Harbor Freight ;-))

If it screws up, be sure just to kill cheap electronics.... Sort of like setting off explosives...

Cheers,

        Terry


At 09:10 PM 1/23/2006, you wrote:
Hi all,

I am pondering a way to reliably measure 10 KVDC
across the terminals of (2) 100 µFd energy dis-
charge caps that I plan to build a quarter shrinker/
can crusher project with. I will have up to a total
of 450 µFd at 10 kV when I get 2 other 120
µFd, 10 kV caps added to my collection. Anyway,
I was originally going to just use my Beckman HV
probe in combo with one of my DVMs to monitor
the voltage at the cap terminals to insure that I
do not overvolt the caps, since my HVDC supply
can go up to about 20 kVDC. However, I believe
the HV probe isn't desinged to be used like this
as its ergonomics lends it for hand held operation
so I was thinking of getting some 10K or 100K
carbon resistors and building a 100 resistor di-
vider to get a 100:1 reduction to safely
read 10 kV on my DVM as 100 volts. What
are the best resistance values to go for 10 K
or 100 K? A 1 Meg total with 10K(X100) would
still allow 10 mA of current flow at 10 kV and that
would translate to 100 watts (WOW)! I suppose
that I just answered my own question- don't think
(100) 1/4 resistors would take much of that! Better go
for 100 K per resistor, that would only allow up to 1 mA
of current flow at 10 kV and 10 watts. I believe 10
watts spread over (100) 1/4 watt resistors would work ;^)
Any comments or suggestions?

David Rieben