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Re: Questions about current
Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Mddeming-at-aol-dot-com>
Hi Peter, Matt, All,
In a message dated 5/4/01 9:54:27 PM Eastern Daylight Time, tesla-at-pupman-dot-com
> Original poster: "Peter Lawrence by way of Terry Fritz <twftesla-at-uswest-dot-net>
> " <Peter.Lawrence-at-Sun-dot-com>
> 3, you have to be careful when measuring NST outputs or you will blow your
> meter. Terry has a good suggestion for current, put a 1kohm/25watt resistor
> across the NST output (that's a short circuit for all practical purposes
> since the internal res of the NST is 20k-50k) and measure the volts across
> the resistor, 1 volt across 1kohm => 1-ma. Terry recommends a 130vac meter
> for NSTs up to 120-ma.
Suppose you want to measure more than just the short-circuit current. What
would the procedure be then?
> to measure volts, make a hugh voltage divider with a long string of very
> valued resistors (like 10 * 1MegOhm for 10:1, or 10*1MegOhm + 100KOhm for
> 100:1, or 10*1MegOhm + 10KOhm for 1000:1).
Since power = E^2/R, at 15kv your voltage divider would be dissipating 22.5
watts or 2.25Watts per resistor. 1Meg 3W-5W resistors are a little pricey and
bulky. If you multiply everything by 10, (e.g. 10 10Meg resistors and a 100K
for 1000:1) the string would dissipate 2.25 Watts or 0.225W per resistor --->
1/2 watt 10Meg 5% resistors wouldn't even get warm overnight and are only a
few cents each.
Are there a disproportionate number of coiler named Matt?